e2 renwable energy resource potential march 2013 · 2014-01-06 · table 1-1: potential renewable...

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Technical Paper E2 An Assessment of the Renewable

Energy Resource Potential in Cornwall

Cornwall Council March 2013

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Table of Contents

1 Summary .......................................................................................... 7 2 Onshore Wind ................................................................................. 11 2.1 Background ..........................................................................................................11 2.2 Methodology.........................................................................................................11 Resource Constraints .........................................................................................................14 Technical Constraints.........................................................................................................16 Environmental and Social Constraints............................................................................19 2.3 Results...................................................................................................................33 3.3 List of Layers........................................................................................................33 3 Biomass – Energy Crops ................................................................. 35 3.1 Background ..........................................................................................................35 3.2 Methodology.........................................................................................................35 Resource Constraints .........................................................................................................38 Technical Constraints.........................................................................................................39 Environmental/Social Constraints ...................................................................................42 3.3 Results...................................................................................................................45 3.4 List of Layers........................................................................................................46 4 Biomass - Forestry Residue and Waste Wood ................................. 48 4.1 Background ..........................................................................................................48 4.2 Methodology.........................................................................................................48 4.3 Assumptions.........................................................................................................49 4.4 Results...................................................................................................................52 4.5 Waste Wood .........................................................................................................53 4.6 Summary ..............................................................................................................54 4.7 List of Layers........................................................................................................55 5 Waste ............................................................................................. 56 5.1 Background ..........................................................................................................56 5.1 Methodology.........................................................................................................57 Technical Constraints - Feedstock Assumptions ..........................................................59 Technical Constraints - Technological Assumptions ....................................................61 5.3 Results...................................................................................................................63 6 Livestock Slurry .............................................................................. 66 6.1 Background ..........................................................................................................66 6.2 Methodology.........................................................................................................66 6.3 Assumptions.........................................................................................................67 6.4 Results...................................................................................................................68 7 Hydropower.................................................................................... 71 7.1 Background ..........................................................................................................71 7.2 Methodology.........................................................................................................71 7.3 Results...................................................................................................................72 8 Solar Resource................................................................................ 75 8.1 Background ............................................................................................................75 8.2 Methodology.........................................................................................................76 Rooftop deployment ...........................................................................................................79 Domestic rooftops ..............................................................................................................79 Rooftop deployment - Non-domestic rooftops..............................................................80 Ground-Mounted Solar PV Deployment .........................................................................82 8.3 Results.................................................................................................................100 8.4 List of Layers......................................................................................................101 9 Solar Thermal ............................................................................... 103

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9.1 Background ........................................................................................................103 9.2 Methodology.......................................................................................................103 9.3 Results.................................................................................................................106 10 Geothermal................................................................................... 107 11 Future improvements ................................................................... 109 12 Conclusions .................................................................................. 110 List of Acronyms................................................................................. 111 Appendix ............................................................................................ 112 Appendix 1: Output per LCA when cumulative impact considerations (density factors) applied. ................................................................................................................113 Appendix 2: Capacity Factor of Wind Farms in Cornwall .........................................116 Appendix 3: Calculated outputs for solar PV systems in Cornwall.........................119

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Tables Table 1-1: Potential Renewable Electricity Resource in Cornwall....................... 8 Table 1-2: Potential Renewable Heat Resource in Cornwall.............................. 8 Table 1-3 - Existing Onshore Installed Renewable Electricity and Heat Capacity in Cornwall .................................................................................................. 9 Table 2-1: Summary of Constraints ........................................................... 14 Table 2-2: Turbine heights selected to reflect the varying landscape strategies across Cornwall ...................................................................................... 24 Table 2-3: Wind turbine separation distances.............................................. 25 Table 2-4: Average separation distances between wind turbines in Cornwall.... 26 Table 2-5: Installed capacity per square kilometre for all turbines sizes included in the assessment ................................................................................... 26 Table 2-6: Wind energy development sizes and total output per LCA .............. 29 Table 2-7: Density factors to represent the spread and grouping of wind turbines for each landscape strategy type............................................................... 31 Table 2-8: Total potential installed electricity generation capacity from wind energy development in Cornwall. .............................................................. 32 Table 2-9: Potential average annual electricity output from wind turbines in Cornwall ................................................................................................ 33 Table 2-10: Summary of total average yearly electricity generation capacity potential from wind energy development in Cornwall.................................... 33 Table 2-11: Summary of the GIS layers used in the wind assessment. ........... 34 Table 3-1: Summary of Constraints ........................................................... 36 Table 3-2: Summary of Crop Yields Based on ALC ....................................... 39 Table 3-3: Summary of Yield Results based on the technical constraints ......... 41 Table 3-4: Summary of available land for biomass, based on the technical and environmental constraint ......................................................................... 44 Table 3-5: Summary of Potential Generation from 100% of Available Land...... 45 Table 3-6: Summary of Potential Generation from 5% of Available Land ......... 46 Table 3-7: Summary of total average yearly electricity and heat generation capacity potential from biomass in Cornwall................................................ 46 Table 3-8: Summary of the GIS layers used in the energy crop assessment .... 47 Table 4-1: Summary of Forestry Residue Energy Generation Potential in Cornwall............................................................................................................ 52 Table 4-2: Summary of Total Forestry Residue Potential ............................... 54 Table 4-3: Summary of total average yearly electricity and heat generation capacity potential from biomass in Cornwall................................................ 55 Table 4-4: Summary of the GIS layers used in the forestry residue assessment55 Table 5-1: Summary of Technological Conversion Efficiencies........................ 62 Table 5-2: Energy generation potential from Energy from Waste ................... 64 Table 5-3: Energy generation potential from Anaerobic Digestion and Energy from Waste ............................................................................................ 64 Table 5-4: Energy generation potential from Gasification .............................. 65 Table 5-5: Summary of total average yearly electricity and heat generation capacity potential from waste in Cornwall ................................................... 65 Table 6-1: Summary of Slurry Production................................................... 68 Table 6-2: Summary of Livestock Population............................................... 68 Table 6-3: Summary of the minimum total potential .................................... 69 Table 6-4: Summary of the maximum total potential ................................... 69 Table 6-5: Summary of minimum available potential.................................... 70 Table 6-6: Summary of maximum available potential ................................... 70 Table 6-7: Summary of total average yearly electricity and heat generation capacity potential from livestock slurry in Cornwall ...................................... 70

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Table 7-1: The estimated output from hydropower sites based on their level of sensitivity. ............................................................................................. 72 Table 7-2: Summary of total average yearly electricity generation capacity potential from hydroelectricity installations in Cornwall................................. 74 Table 8-1: Summary of irradiance levels for Truro ....................................... 76 Table 8-2: Summary of estimated domestic electricity production .................. 79 Table 8-3: Summary of estimated domestic electricity production .................. 81 Table 8-4: Technical and environmental constraints to ground mounted solar PV development .......................................................................................... 83 Table 8-5: Solar PV development sizes selected to reflect the varying landscape strategies across Cornwall ........................................................................ 93 Table 8-6: Solar PV Development sizes and total output per LCA ................... 97 Table 8-7: Density factors applied to represent the spread and grouping of solar PV developments for each landscape strategy type. ..................................... 98 Table 8-8: Total potential installed electricity generation capacity from ground-mounted solar PV in Cornwall. .................................................................. 99 Table 8-9: Total annual output per size of Solar PV system ..........................100 Table 8-10: Potential average annual electricity output from ground-mounted solar PV development in Cornwall.............................................................100 Table 8-11: Summary of average yearly electricity generation capacity potential from solar PV in Cornwall for each scale of PV deployment. ..........................101 Table 8-12: Summary of total average yearly electricity generation capacity potential from solar PV in Cornwall ...........................................................101 Table 8-13: Summary of the GIS layers used in the wind assessment. ..........102 Table 9-1: Summary of Total Average Yearly Thermal Generation Capacity Potential from Domestic Solar Thermal in Cornwall. ....................................106

Figures Figure 2-1: The wind energy generation assessment process ........................ 13 Figure 2-2: Map of Minimum Economic Wind Speed (5.5 m/s at 10m height)... 16 Figure 2-3: Map of Technical Constraints .................................................... 19 Figure 2-4: Map of the Environmental and Social Constraints ........................ 21 Figure 2-5 Unconstrained Areas for Wind Turbines in Cornwall (not including landscape designations)........................................................................... 22 Figure 3-1: The biomass energy generation assessment process.................... 37 Figure 3-2: Map of Agricultural Land Classification ....................................... 39 Figure 3-3: Map of Arable Land and Wind Speeds greater than 7 m/s ............. 41 Figure 3-4: Map of suitable areas for biomass crops based in the technical constraints............................................................................................. 42 Figure 3-5: Map of the environmental and social constraints ......................... 43 Figure 3-6: Map showing the available land for biomass, based on the technical and environmental constraint ................................................................... 44 Figure 4-1: The forestry residue and waste wood energy generation assessment process ................................................................................................. 49 Figure 4-2: Map of All Woodland greater than 2 hectares.............................. 51 Figure 5-1: The waste energy generation assessment process....................... 58 Figure 6-1: The livestock slurry energy generation potential process .............. 67 Figure 7-1: The hydropower resource assessment process ............................ 71 Figure 7-2: Sites for hydropower in Cornwall based on their potential installed capacity................................................................................................. 73 Figure 8-1: Map of UK global irradiance levels on an optimally inclined plane... 75 Figure 8-2: The Solar PV energy generation assessment process ................... 78 Figure 8-3: Land already in use for non-solar PV development....................... 84

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Figure 8-4: Land in Cornwall with a southerly aspect.................................... 85 Figure 8-5: Environmental designations in Cornwall ..................................... 86 Figure 8-6: Historic urban designations in Cornwall...................................... 87 Figure 8-7: Historic features and monuments in Cornwall ............................. 88 Figure 8-8: Best and Most Versatile agricultural land in Cornwall ................... 89 Figure 8-9: Distribution of National Grid infrastructure down to the 33kV line, with 2000m buffer. ................................................................................. 90 Figure 8-10: Technically and environmentally unconstrained land for ground mounted solar photovoltaic development.................................................... 91 Figure 9-1: The solar thermal resource assessment process .........................104 Figure 10-1: Map of Heat flow at the Surface .............................................108

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1 Summary 1. Cornwall Council is currently in the early stages of developing a Local

Development Framework for Cornwall. As part of the Development Framework, a Local Plan is required which will deliver the strategic planning strategy for Cornwall up to 2030. The plan will include policies to guide the nature and location of renewable energy installations in Cornwall. In order to develop these policies an evidence base is required to provide an understanding of the potential to generate electricity and heat from renewable sources. The purpose of this report is to set out that steps taken to assess the renewable energy resource and provide the findings of the assessment.

2. The current renewable electricity targets for Cornwall are 93MW by 2010.

There is currently (October 2012) 172.99 MW of installed electricity in Cornwall.

3. The following onshore renewable resources were considered in the

assessment:

Onshore Wind Biomass – Energy Crops Biomass – Forestry Residue Energy Recovery from Waste Livestock Slurry Hydropower Solar – Photovoltaic (electricity) Solar – Thermal (heat) Geothermal

4. There are four intended outcomes of this report:

a) a complete comprehensive methodology to each resource

assessment; b) the spatial mapping of the potential renewable resources (those that

can be mapped); c) the spatial mapping of the various technical, environmental and

social constraints to different renewable energy resources; d) the statistical result of the potential for renewable energy in Cornwall.

5. The methodology used to calculate the potential heat and electricity

generation potential of each resource are described in the technology

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sections. The figures below provide a summary of the total electricity and heat generation potential from renewable energy sources in Cornwall.

Electricity

Potential Installed capacity (MW)

Average capacity factor of technology

Potential GWh per year

Potential in thousand tonnes of oil equivalent per year (ktoe).

Solar 986.368 0.1 872.592 75.029

Wind 402.502 0.3 1,057.775 90.95

Hydro 1.954 0.6 10.270 0.883

Biomass – Energy Crops 1.824 0.24 15.978 1.374

Biomass – Forestry Residue

5.194 0.24 45.499 3.912

Waste – Energy Recovery

12 – 24.14 - 86 – 169.2 7.39 – 14.55

Livestock Slurry 2.62 – 5.55 0.75 & 0.33 22.95 – 48.618 1.97 – 4.18

Total 1412.462 – 1427.532

- 2111.064 – 2219.932

181.508 – 190.878

Table 1-1: Potential Renewable Electricity Resource in Cornwall

Heat

Potential constrained installed capacity (MWth)

Average capacity factor of technology

Potential GWh per year

Potential in thousand tonnes of oil equivalent per year (ktoe).

Biomass – Energy Crops 4.261 0.56 37.326 3.209

Biomass – Forestry Residue

12.118 0.56 106.154 9.128

Waste – Energy Recovery

20 – 40.2 - 143.3 – 281.7 12.32 – 24.28

Livestock Slurry 6.28 – 13.16 0. 75 & 0.67 55.024 – 115.29

4.73 - 9.913

Solar Thermal 119.953 0.46 94.591 8.13

Total 162.612 – 189.692

- 436.395 – 635.065

35.517 – 54.66

Table 1-2: Potential Renewable Heat Resource in Cornwall.

Installed Capacity (MW) Permitted (not yet

operational) capacity (MW)

Technology

Electricity Heat Electricity Heat Ground-mounted non-domestic PV

104.54 - 146.869 -

Roof mounted PV 19.5264 - - - Wind 90 - 69 - Hydro 1.69 - 0 - Solar Thermal - 1.67 - 0 Deep Geothermal 0 0 15 58.5

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Heat Pumps - 5.881 - 0 Anaerobic Digestion 0 0 0 0 Biomass 0 19.843 0 0 Landfill Gas 10.28 0 0 0 Sewage Gas 0.5 0.955 0 0 Energy from Waste 0 0 20 78

Total 226.5364 28.349 250.869 136.5

Table 1-3 - Existing Onshore Installed Renewable Electricity and Heat Capacity in Cornwall

6. To assess the potential to generate electricity and heat from renewable

energy resources a spatial and statistical analysis was used. Those resources/technologies that are geographically constrained were analysed and mapped using Geographical Information System (GIS) software. These included wind, biomass (energy crops and forestry residue), hydropower and ground-mounted solar PV. The remaining resources were calculated through a statistical analysis.

7. The assessment of the potential electricity generation form the wind

resource in Cornwall was based on a spatial assessment of the technical, environmental and social constraints to the installation of wind turbines. The wind resource has the second greatest potential of all the resources assessed and makes up around 28% of Cornwall’s renewable electricity potential. The assessment estimates a potential of just over 402 MW from wind energy development within Cornwall.

8. The assessment of both biomass resources (energy crops and forestry

residues) considered the locations where these resources could potentially be grown, rather than identify suitable locations for biomass fuelled energy generation plant. The combined capacity from energy crops and forestry residue makes up 1.4% of the total renewable energy potential (electricity and heat) for Cornwall – a potential total installed capacity of just over 23 MW.

9. The livestock slurry assessment was based on as an assessment of the

total biogas yield from cattle, pigs and poultry in Cornwall. The electrical potential from livestock slurry ranged from 2.62 to 5.55 MW and the heat capacity ranged from 6.28 – 13.16 MW (installed capacity) and would provide a means of disposing of over one million tonnes of livestock slurry per annum.

10. The assessment of the potential electricity for hydro electricity generation

in Cornwall based on an Environment Agency report1. The report assigns a

1 ‘Opportunity and environmental sensitivity mapping for hydropower in England and Wales’ http://publications.environment-agency.gov.uk/PDF/GEHO0310BRYF-E-E.pdf

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level of sensitivity to each potential hydro electricity generation site. A significant proportion of these sites identified in the report are considered highly sensitive to impacts on the environment. These highly sensitive sites therefore were discounted from the resource assessment. The less sensitive sites have the potential to provide a total installed capacity of 1.954 MW of electrical energy.

11. Cornwall has one of the highest solar irradiation levels in the UK. The

potential yield was calculated through a statistical assessment of the potential rooftop mounted system capacity i.e. the availability of compatible rooftops, and by applying a series of technical, social and environmental constraints to ground-mounted systems. Solar PV offers the resource with the greater potential in Cornwall is solar PV. The total capacity amounts to 986MW – 69% of the total renewable electricity potential in Cornwall.

12. At present, there is commercial interest in two geothermal projects in

Cornwall (planning permission granted). However, the systems are yet to be installed and some uncertainties remain. After careful consideration, it was decided that geothermal would not be investigated as part of this assessment. There is insufficient information about the constraints to and potential of the geothermal resource at present. The output of any given system is dependent on a number of project specific factors. In the absence of installed systems in Cornwall, this means that providing an assessment that goes beyond a geological assessment of the inferred resource is very difficult.

13. Overall the resource assessment suggests that a total of 1575 - 1617

MW of renewable energy can be installed in Cornwall with the potential to generate up to 3,076 GWh per annum. This figure represents the renewable energy capacity that is considered reasonably possible to install in Cornwall. The figure does not include the existing installed capacity in Cornwall.

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2 Onshore Wind

2.1 Background 14. Wind power is kinetic energy that is taken from the wind and converted

into mechanical and thus electrical energy through a wind generator (more commonly referred to as a wind turbine). Wind turbines can be deployed singularly or clustered together as a wind farm. While there are many designs and manufacturers of wind turbine the most commonly seen is an upwind three bladed horizontal axis turbine.

15. This assessment aims to consider the resource potential and deployment

opportunities in Cornwall for wind energy. It is acknowledged that the waters off the South West of the UK offer significant potential for offshore wind energy development. This potential has not been assessed as part of this assessment, because the marine environment (below the mean low water mark) is not under the remit of the local planning authority.

16. An initial assessment of renewable energy potential in Cornwall was

completed in 2009 (the 2009 report). The assessment looked at the resource potential and constraints within the County. A copy of the report can be found at http://democracy.cornwall.gov.uk/mgConvert2PDF.aspx?ID=20021

17. Since the completion of that (2009) assessment, a Renewable and Low-

carbon Energy Capacity Methodology – Methodology for the English Regions was produced commissioned by the Department of Energy and Climate Change (DECC). (The DECC report).

http://www.decc.gov.uk/assets/decc/What%20we%20do/UK%20energy%20supply/Energy%20mix/Renewable%20energy/ORED/1_20100305105045_e_@@_MethodologyfortheEnglishregions.pdf

18. Both the above methodologies have been considered in the development

of the resource methodology assessment set out below.

2.2 Methodology

19. The methodology outlined below sets out an assessment of the wind

energy potential in Cornwall based a sequential application of a range of constraints to the installation of wind turbines. For the purposes of the assessment the technical and environmental constraints were modelled

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using a 100m high turbine. This represents the approximate height of the tallest turbine currently installed in Cornwall. As such it was selected to provide a cautious approach that does not overstate the resource potential.

20. The diagram below sets out the process undertaken to assess the wind

energy resource potential.

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Wind Resource Assessment

Resource Constraints

Wind speeds

Technical Constraints

HighwaysRailwaysWatercoursesElectricity Grid Infrastructure

Undevelopable areas (e.g. forests, lakes etc)

Environmental /Social Constraints

Residential Amenity

Special Protection Areas / Special Areas of Conservation

National Nature Reserves

Sites of Special Scientific Interest

World Heritage Site

Landscape Character

Identify the appropriate development sizes for the landscape

Resize the unconstrained sites to the appropriate size for the landscape

Cumulative Impact

Aggregate the total output for each landscape character area and apply

cumulative density factors

Convert the total installed capacity into net capacity, annual generation (GWh) and

thousand tonnes of oil equivalent.

Wind Resource Assessment


Wind speeds


HighwaysRailwaysWatercoursesElectricity Grid Infrastructure

Undevelopable areas (e.g. forests, lakes etc)


Residential Amenity

Special Protection Areas / Special Areas of Conservation



World Heritage Site

Landscape Character

Identify the appropriate development sizes for the landscape

Resize the unconstrained sites to the appropriate size for the landscape

Cumulative Impact

Aggregate the total output for each landscape character area and apply

cumulative density factors



Figure 2-1: The wind energy generation assessment process

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Constraints 21. The wind resource assessment consisted of a strategic spatial analysis of

the potential to generate energy from the available wind resource in Cornwall. GIS mapping software has been used to create a series of layers that represent each constraint. The process started with the assumption that the entire area of Cornwall is being available for wind developments. Each constraint was then applied to restrict the total area, thereby reducing the total potential. The process continued by applying all the constraints until only the unconstrained areas remained. These remaining areas represented those with the potential for wind development.

22. The constraints to wind energy development were divided into three

categories. These included resource, technical and environmental/social constraints. The resource constraints were applied to define the total resource. The technical constraints were defined by the technical resource i.e. where siting wind turbines is technically possible and economically viable. The environmental/social constraints were applied to define the accessible resource. The constraints used in this study are summarised in Table 2-1 and are discussed in the following sections.

Resource

Constraints Technical Constraints Environmental Constraints

Minimum wind speed of 5.5m/s at 10m.

150m road buffer (down to and including B roads). 150m rail network buffer. 20m river/watercourse buffer. 100m buffer along WPD 33 and 132 kV distribution grid No deployment in areas of geographical restriction

400m noise buffer around residential properties. Special Protected Areas (SPA) Special Areas of Conservation (SAC) National Nature Reserves (NNR) Sites of Special Scientific Interest (SSSI) World Heritage Sites (WHS) Assessment of the landscape capacity for of wind and large scale PV development in Cornwall.

Table 2-1: Summary of Constraints


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23. The main source of information on the UK wind resource is the NOABL (National Oceanic and Atmospheric Administration Boundary Layer) wind speed database produced for the former Department of Trade and Industry. It can be found at the following link: http://www.decc.gov.uk/en/content/cms/what_we_do/uk_supply/energy_mix/renewable/explained/wind/windsp_databas/windsp_databas.aspx

24. The database contains estimates of the annual mean wind speed

throughout the UK at a height of 10m, 25m and 45m above ground level (agl). The database has a resolution of a 1km grid square.

25. In order to identify a minimum economic wind speed, view of both

academia and industry were sought. A level of 5.5m/s at 10m above ground level was recommended.

26. One limitation of the NOABL dataset is its resolution. A 1km square

resolution is useful at the strategic and regional levels, but it does not allow for variations in local topographical effects and surface roughness. Although using the 45m wind speed dataset would provide a closer estimate to the hub height of size of turbine modelled in this part of the study, the minimum economic wind speed would need to be readjusted for wind shear effects, up to this level. As the wind shear is affected greatly by local topography and the surrounding environment (i.e. trees, walls, buildings etc) it is more appropriate to use the 10m dataset with a known minimum economic wind speed at the same level. Therefore, all grid squares with a wind speed below 5.5m/s at 10m height were removed from the dataset, as shown in Figure 2-1.

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© Crown copyright. All rights reserved Cornwall Council, 100049047, 2011.

Figure 2-2: Map of Minimum Economic Wind Speed (5.5 m/s at 10m height).

Technical Constraints 27. The Highway Agency Wind Farm Good Practice Guide2 states that ‘although

a wind turbine erected in accordance best practice should be a stable structure, it may be advisable to achieve a set-back from roads and railways of at least fall over distance (height measured to blade tip), so as to achieve maximum safety.…commercial turbines should be set back by a distance equating to their height plus 50 metres where possible’. Assuming that the tip height of the turbine in this study is 100m, the recommended minimum set back distance from trunk roads is 150m.

28. In Cornwall there are only two trunk roads: the A30 and the A38. The

remainder of the road network is maintained by Cornwall Council. Although the Highway Agency’s guidelines only apply to trunk roads, for the purposes of this assessment they were also applied to the remaining road network down to and including B roads. The B road network in Cornwall is just as extensive as the A road network and a road safety margin for both categories of road would provide a suitably cautious approach on road safety grounds.

2 http://www.highways.gov.uk/aboutus/documents/CRS_558501_WindFarmGoodPracticeGuide.pdf

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29. Any disturbance to the rail network in Cornwall would have significant implications. However, despite this the rail operator has no official policy on wind turbines near rail tracks. In discussion with the operator, it was agreed that the same minimum set back distance between a trunk road and a wind turbine would be applied to the rail network. Therefore, for the purposes of this assessment, a minimum set back distance of 150m was applied to the rail network.

30. Rivers and watercourses are unlikely to present a significant problem to

wind farms. Watercourses are generally found at the bottom of valleys whereas the best sites for wind farms are generally found at the top of a hill or valley (higher ground where exposure to wind can be maximised). However, there may be occasions where watercourses and good wind resources meet.

31. It is recognised that moisture content may affect ground conditions near

watercourses and thus wind turbine foundation design, but it was not practical to attempt a detailed assessment of the varying moisture content in the ground and its likely impact. Consideration was, however, given to the areas identified as being of high and medium probability flooding. The National Planning Policy Framework states that inappropriate development in areas at risk of flooding should be avoided by ‘directing development away from areas at highest risk, but where development is necessary, making it safe without increasing flood risk elsewhere’3. The Framework indicates that Planning Policy Statement 25: Development and Flood Risk - Practice Guide4 sets out how this policy should be implemented. The Practice Guide describes renewable energy installations as ‘essential infrastructure’ which may be accommodated within areas of flood risk. Therefore, for the purpose of this study, areas of flood risk can be has not been considered a constrained to wind energy development.

32. With regard to Ministry of Defence sites and the potential impact of wind

turbines on radars, it is a requirement that the MoD are consulted on all proposals for wind turbines over 11m metres tip height or with a rotor diameter over 2 metres. There are no areas that specifically prohibit wind turbines and each turbine will be considered individually. It was therefore not considered possible to have a constraint on certain areas with regard to this.

33. The proximity of a wind farm to the electricity distribution grid can have a

significant effect on economic cost. Whilst this report is not focusing on the economics, it is relevant to the realisation of Cornwall’s onshore wind energy potential. Electrical cabling is costly. 100m of low voltage mains cable and

3 http://www.communities.gov.uk/documents/planningandbuilding/pdf/2116950.pdf 4 http://www.communities.gov.uk/documents/planningandbuilding/pdf/pps25guideupdate.pdf

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ground works can cost between £50 and £110 per metre5. The large variation in the cost is due to restoring any ground works to its original condition. Therefore, a wind farm needs to be as close as possible to a distribution line. However, it cannot be too close to a line in case a turbine collapses. Therefore, in order to maintain a safe separation limit without greatly increasing the costs of the cabling, a minimum separation distance of topple height was applied. The standard size turbine used in this assessment is 100m to tip height so a 100m stand off from electricity grid lines (33 + 132 kv) was applied. Whilst overhead line clearances can be found in the Energy Networks Association Technical Specification 43-8 Issue 3 (2004), there are none that apply to wind farms. Furthermore, a 100m clearance also mitigates any potential hazards that a crane may present in the construction, maintenance or decommissioning of a wind farm.

34. In order to make sure that areas technically suitable for a wind farm are

realistic, certain geographical constraints need to be applied. For example, significant levels of forestry clearance to enable the siting of a wind farm would be undesirable. It has therefore been assumed that areas of forestry, rivers, watercourses, lakes and reservoirs will be excluded from those with potential for wind farm development.

35. Figure 2-2 shows a map of the constraints outlined above. The white areas

show the areas of land which are unconstrained by technical factors. They are therefore considered to be technically suitable sites for a wind farm development.

5 United Utilities Electricity Plc: Statement of Methodology and Charges for Connection to United Utilities Electricity Plc’s Electrical Distribution Network, [Online], Available: http://www.unitedutilities.com/Documents/ENW_-_Statement_of_Methodology_and_Charges_for_Connection_to_Electricity_Distribution_Network_1_Apr_09.pdf [24 Feb 10].

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Figure 2-3: Map of Technical Constraints Environmental and Social Constraints Designated sites 36. The following International/National and local environmental designations

were considered within this assessment: Special Protected Areas; Special Areas of Conservation; Sites of Special Scientific Interest; National Nature Reserves; Cornwall and West Devon Mining Landscape World Heritage Site.

37. Due to the importance of these designations, it is assumed that for the

purposes of this assessment, no wind turbines will be developed within these designations.

38. There are no RAMSAR sites designated in Cornwall. The Area of Outstanding

Beauty (AONB) designation applies to the greatest area of land in Cornwall to which environmental designations apply. The AONB is concerned with

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protecting natural beauty. For the purposes of this assessment natural beauty has been interpreted as being primarily a landscape matter. As a result the degree to which the AONB constrains within turbine development in Cornwall is dealt with in the landscape section (paragraph 46 – 47).

Noise 39. There are two sources of noise generated from wind turbines: mechanical

noise and aerodynamic noise. Over the past twenty years, there have been significant reductions in the noise generated by the mechanics of turbines (i.e. gearboxes etc) but wind turbines still generate some noise. In order to adequately protect residential properties from noise generation, the former Department for Trade and Industry, established a Working Group on Wind Farm Noise. The working group produced a report making recommendations for noise restrictions.

40. The Working Group’s report ‘The assessment of and rating of noise from

wind farms’ makes reference to the experience of mainland Europe and concludes that there is unlikely to be significant noise problems for residential properties further than 400m from a wind turbine. However, it is recognised that factors such as topographical effects mean that a minimum separation distance of 400m cannot be relied upon to provide adequate protection in all cases. A noise restriction of 35-40dB at a property is the preferred method of protection6. For the purpose of this study however, the minimum separation distance (of 400 metres) has been used with the understanding that any further site specific studies will need to use noise limits rather than a separation distance.

41. The 400m noise buffer was applied to every place of residency where there may be a potential for disturbing sleep. This includes homes, hotels, inns, hospitals, hospices, holiday cottages, holiday parks and jails. Using address point information held by Cornwall Council the 400m buffer was applied to each of these types of property.

6 Department for Business, Enterprise & Regulatory Reform, The assessment of and rating of noise from wind farms [Online], available: http://webarchive.nationalarchives.gov.uk/+/http://www.berr.gov.uk//energy/sources/renewables/explained/wind/onshore-offshore/page21743.html [22 Jul 09]

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Figure 2-4: Map of the Environmental and Social Constraints

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Figure 2-5 Unconstrained Areas for Wind Turbines in Cornwall (not including landscape designations).

42. In order to ensure that the remaining unconstrained sites are large enough

to accommodate commercial scale wind turbines, all sites with an area less than 250m2 were discounted. The minimum area of 250m² was chosen to represent the required area for 100m high wind turbine hexagonal foundation with a width of 17.5m.

Landscape Constraints 43. The impact on the character of the landscape is an important consideration

for the deployment of wind turbines in Cornwall. Traditionally, however, resource assessments have paid little attention to this issue, or made broad assumptions about separation distance that do not have a specific relationship with the landscape in question. A detailed evidence base is required to inform decisions about the scale and amount of wind energy development that might be accommodated within a given landscape. This section sets out the detailed steps that the resource assessment has taken to address this issue.

44. The landscape strategy set out in the report entitled ‘An Assessment of the

Sensitivity of the Landscape to On Shore Wind Energy and Large Scale

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Solar Photovoltaic Development in Cornwall’7 (the ‘Assessment’) provides the advice on the relationship between wind energy development and the landscape across Cornwall. This report has been used to refine the results of the technical and environmental wind energy potential assessment to reflect the character of the landscape.

45. The Assessment set out a landscape strategy for each of Cornwall’s 40

Landscape Character Areas (LCAs)8 based on the sensitivity of LCA. The following four landscape strategy types were developed for Cornwall as part of the Assessment: Wind Farm landscapes; Landscapes with wind energy development; Landscapes with occasional wind energy development; Landscapes without wind energy development.

46. One of the four strategy types was applied to each of Cornwall’s LCAs to

reflect the level of sensitivity of the landscape at each area. The study found that there were no ‘wind farm landscapes’ in Cornwall.

47. Within Cornwall ‘landscapes without wind energy development’ generally

consist of moor land and those areas designated as Areas of Outstanding Natural Beauty, or Heritage Coast. In most of these cases the landscape strategy stated that very small turbines associated with buildings might be acceptable, but in general the landscape should be kept free of turbines if its characteristics were not to fundamentally altered. The resource assessment discounted those sites which fell within these designated landscapes. This was done to reflect the local and national importance of these landscapes. This approach is supported by the National Planning Policy Framework9, which states that ‘great weight should be given to conserving landscape and scenic beauty in...Areas of Outstanding Natural Beauty, which have the highest status of protection in relation to landscape and scenic beauty.’

48. The exception to this rule was LCA07. The strategy advised that areas of

recently enclosed land in the northern part of the LCA may have a greater flexibility to accommodate turbines larger than domestic scale. Indeed this part of the LCA has 6 turbines of approximately 100m in height installed at present. In this case, due to the specific variations in this particular area of landscape the resource assessment has not discounted the LCA.

7 An Assessment of the Sensitivity of the Landscape to On Shore Wind Energy and Large Scale Solar Photovoltaic Development in Cornwall (Land Use Consultants, 2011). 8 Cornwall and Isles of Scilly Landscape Character Study. 2007. http://www.cornwall.gov.uk/default.aspx?page=24874 9 http://www.communities.gov.uk/documents/planningandbuilding/pdf/2116950.pdf

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49. Having discounted the AONB and the Heritage Coast, the detailed information contained within each strategy was used to estimate the appropriate size and number of wind turbines that might be realistic for each of the sites that were identified by applying the technical and environmental constraints.

50. The following section details the steps taken to refine the resource

assessment to reflect the information within landscape strategy. These steps have been listed below:

Step Action

1 Identify the appropriate size of development for each LCA

2 Refine the technically and environmentally unconstrained sites to reflect the appropriate size for each LCA

3 Refine totals to take account of potential cumulative impact Step 1: Identify the appropriate size of development for each LCA 51. In order to refine the technically and environmentally unconstrained sites

to reflect the appropriate size and yield (for the landscape), the appropriate height of turbine for each LCA was established using the details contained within each LCA strategy.

52. The table below sets out the turbine heights and indicative energy output

(the installed capacity) chosen to represent the different scales of development that can be accommodated in the landscape across Cornwall, based on the strategy for each LCA.

Turbine scale Approximate

average turbine height to tip (interpreted from landscape strategies) (m)

Estimated average installed capacity (MW)

Very small 25 0.025 Small 45 0.4 Medium 85 1 Large 100 2.3

Table 2-2: Turbine heights selected to reflect the varying landscape strategies across Cornwall

Step 2: Refine the technically and environmentally unconstrained sites to reflect the appropriate size for each LCA

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53. In order to calculate the potential capacity of each of the technically and environmentally unconstrained sites it is necessary to understand how many turbines can be accommodated. The separation distance between turbines is fundamental to this. Recent resource assessments conducted elsewhere in the UK and Europe use a range of different assumptions about separation distances. The table below details a number of examples with an estimation of the installed capacity per square kilometre for each example.

Reference Separation

distance/Output density

Yield (MW) (based on a 70m rotor diameter)

Renewable and Low-carbon Energy Capacity Methodology: Methodology for the English Regions (LUC and SQW Energy - http://www.sqw.co.uk/file_download/246)

5 rotor diameters or a benchmark of 9MW/km2 – whichever results in the greater capacity deployment figure

9MW/km2

Europe's onshore and offshore wind energy potential European Environment Agency http://www.energy.eu/publications/a07.pdf

8MW/km2 (no details about turbines sizes and separations)

8MW/km2

Planning Policy Statement 22 Companion Guide10

6x4 rotor diameter ellipse

23MW/km2

Table 2-3: Wind turbine separation distances

54. The table demonstrates the wide range of figures used to represent wind

turbine separation distances and yield per square kilometre. The Companion Guide to Planning Policy Statement 22 recommends that the separation distance should be calculated as 6 times the rotor diameter in the direction of the prevailing wind and 4 times the diameter at 90 degrees to the direction of the wind. This, however, provides a much greater yield than more recent studies. It was considered that none of these studies provides a replicable, clearly justified metric that can be used with confidence in this assessment. An alternative approach has therefore been developed. This alternative approach used the calculated separation

10 Planning for Renewable Energy: A Companion Guide to PPS22 http://www.communities.gov.uk/documents/planningandbuilding/pdf/147447.pdf

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distances of turbines that have been installed in Cornwall to provide a meaningful representation the density that is being achieved here.

55. Existing wind farms in Cornwall were grouped into bands to reflect the size

bands within the landscape strategy. The largest separation distance between wind turbines in each wind farm was recorded and then averaged across the wind farms within each size band. The largest distance was used to provide a figure that was realistic, but cautious, in order to avoid overstating the potential wind turbine density. These average separations distances are listed in the table below.

Turbine scale Approximate

average turbine height to tip (interpreted from landscape strategies) (m)

Average separation distance in Cornwall

Very small 25 50011 Small 45 234 Medium 85 271 Large 100 460

Table 2-4: Average separation distances between wind turbines in Cornwall

56. Based on this approach the installed capacity per square kilometre was

calculated for each of the turbine sizes considered appropriate for the Cornish landscape. These figures are set out in the table below.

Turbine Height to tip (m)

Separation distance (M)

Number of turbines per square kilometre (rounded down)

Installed Capacity per turbine (MW)

Installed Capacity per square metre (MW/km2)

25 500 6 0.025 0.15 45 234 20 0.4 8 85 271 14 1 14 100 460 5 2.3 11

Table 2-5: Installed capacity per square kilometre for all turbines sizes included in the assessment

57. For each LCA the turbine height was selected, based on the information

set out in the landscape strategy. The estimated output associated with 11 This separation distance has been estimated based the approximate spread of existing small turbines where there is clustering in Cornwall (rather than a measured distance).

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the selected turbine height (see table 2-2 above) was then used to calculate the overall installed capacity from the technically and environmentally unconstrained sites within the LCA.

58. Where a particular strategy for an LCA included two scales of development

(e.g. small and very small) a cautious approach was adopted (i.e. the turbine height selected reflected the higher end of the very small scale).

59. The table below sets out the potential total installed capacity for each LCA.

Note that it does not include those LCAs that either had no unconstrained sites, or were discounted due to their landscape value (AONB, Heritage Coast).

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Landscape Character Area

Landscape Strategy Type Approximate Turbine Height (to blade tip) (m)

Estimated Output /km2 (MW)

Unconstrained area (km2)

Potential Installed Capacity (MW) (with Technical and Environmental constraints)

4 Landscape with occasional single, or small clusters of turbines up to and including the medium scale

85 14 0.64 8.96


85 14 0.02 0.28


85 14 2.90 40.60

7 Landscape without wind turbines except on the plateau to the north where large turbines might be accommodated

100 11 6.22 68.42

9 Landscape with occasional single, or small clusters of turbines up to the medium scale

85 14 0.69 9.66

10 Landscape with occasional single, or small clusters of turbines up to the smaller end of the large scale

85 14 2.23 31.22


85 14 0.42 5.88

13 Landscape with occasional single turbines or medium sized clusters of turbines up to an including the medium scale

85 14 6.91 96.74

14 Landscape with wind energy development with small or medium clusters of turbines up to the smaller end of the large scale

100 11 11.69 128.59

15 Landscape with occasional single turbines or small clusters of turbines up to and including the medium scale

85 14 2.89 40.46

16 Landscape with occasional small clusters of turbines, or single turbines up to the lower end of the large scale

100 11 3.67 40.37

17 Landscape with occasional small, medium or large clusters of turbines up to the large scale

100 11 4.55 50.05

18 Landscape with wind energy development comprising small or medium clusters of turbines up to the smaller end of the large scale

100 11 8.57 94.27

19 Landscape with occasional single turbines or small clusters up to and including the medium scale

85 14 3.01 42.14

20 Landscape with occasional single or small clusters of turbines 85 14 2.77 31.78

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up to and including the medium scale

21 Landscape with occasional single or small clusters of turbines up to and including the medium scale

85 14 1.32 18.48

22 Landscape with occasional small or medium clusters of turbines up to the lower end of the large scale

100 11 15.20 167.20

24 Landscape with occasional single turbines of the very small scale

25 0.15 0.91 0.1365


85 14 1.63 22.82

26 Landscape with occasional small clusters of turbines up to the lower end of the large scale

100 11 6.49 90.86

28 Landscape with occasional single of small clusters of turbines up to and including the medium scale

85 14 1.24 17.36

29 Landscape with occasional single turbines of the very small, or small scale

25 0.15 0.14 0.021

31 Landscape with occasional small or medium clusters of turbines up to and including the medium scale

85 14 6.30 88.20

33 Landscape with occasional small or medium scale clusters of turbines up to the smaller end of the large scale

100 11 6.75 74.25

34 Landscape with occasional single or small clusters of turbines up to the and including the medium scale

85 14 2.89 40.46


100 11 12.19 134.09

37 Landscape with occasional single of small clusters of turbines up to the smaller end of the large scale

100 11 21.73 239.03

38 Landscape with occasional single or small clusters of turbines up to the medium scale

85 14 7.82 109.48

39 Landscape with occasional single or small to medium scale turbines up to the smaller end of the large scale

100 11 3.27 35.97

40 Landscape with occasional single or small clusters of turbines up to the large scale

100 11 9.98 109.78

Table 2-6: Wind energy development sizes and total output per LCA

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Step 3: Refine totals to take account of potential cumulative impact 60. The above table provides an understanding of the potential installed

capacity for wind energy development in Cornwall, based on the appropriate size of wind turbine for each of the LCAs. It does not, however, give consideration to the potential cumulative impact of multiple wind turbines on the landscape.

61. In order to take account of the cumulative impact considerations

associated with multiple wind turbines within the landscape, consideration needs to be given to their appropriate spread (or distribution).

62. Cumulative impact can only be truly assessed on a case by case basis, but

this assessment has attempted to make a strategic allowance for it by assigning a density factor to each landscape strategy type (as shown in the table below) to represent proportion of development that might be accommodated in the landscape without fundamentally altering its character.

63. As set out in paragraphs 44 and 45, the landscape assessment assigned

landscape strategy types to each landscape. Further detail was added to reflect the appropriate size and grouping of wind turbines within each LCA.

64. For each landscape strategy type (i.e. where the strategy suggested a

similar approach to cumulative impact was appropriate) a density factor was developed to represent the spread of turbines across the LCA. This was supplemented by a further density factor designed to reflect the size of the clusters considered appropriate for each LCA. The density factors are set out in the table below.

Landscape Strategy Type Density

Factor (%)

Cluster Size Density Factor (%)

Single Turbines 20 Small Clusters 40 Medium Clusters 60 Large Clusters 80

Landscape with turbines 80

Very Large Clusters

100

Single Turbines 20 Small Clusters 40 Medium Clusters 60 Large Clusters 80

0Landscape with occasional turbines

50

Very Large Clusters

100

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Table 2-7: Density factors to represent the spread and grouping of wind turbines for each landscape strategy type.

65. The potential installed capacity total for each LCA of the same landscape

character types was then combined, thus giving an aggregated total installed capacity for each landscape type.

66. The relevant density factors were applied sequentially to the aggregated

total for all the LCAs within each landscape strategy type. This was done to take account of the fact that the distribution of technically and environmentally unconstrained sites is not uniform across Cornwall. Consequently, applying a standard density factor at the individual LCA level would be misleading.

67. For example: Consider an LCA with the strategy ‘landscape with wind

turbines comprising medium scale clusters of turbines’. The LCA has 100 unconstrained hectares. The first density factor to apply would be 80% (to reflect the landscape

with wind farms element) – leaving 80 hectares. The second density factor to apply would be 60% (to reflect the

medium scale clusters) – leaving 48% of the total (48 hectares). 68. Where the landscape strategy advises that, for example, small or medium

clusters are appropriate the density factor to reflect larger of the two was applied, except where the LCA contained or bordered land designated as AONB. In these cases the density factor to reflect the smaller of the two was applied.

69. LCA07 was considered differently to reflect the fact that the strategy is for

a landscape without wind, but includes the caveat that larger than domestic turbines could be accommodated on the plateau. This was interpreted as ‘occasional small scale clusters’ and the density factors were applied accordingly. Appendix 1 sets out the output per LCA after the relevant density factors were applied.

70. Based on these density factors the matrix below shows the total potential

installed capacity for each of the different landscape strategies that arise in Cornwall.

Cluster Size

Single Turbines

Small Clusters

Medium Clusters

Large Clusters

Very Large Clusters

Potential Landscape 0 42.909 106.973 0 0

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with Turbines

Installed Capacity for each Landscape Type (MW)

Landscape with Occasional Turbines

69.926 113.759 48.735 20.2 0

Total Installed Capacity (MW)

402.502

Table 2-8: Total potential installed electricity generation capacity from wind energy development in Cornwall.

71. The above figures show the peak output (installed capacity) for wind

energy in Cornwall. In order to understand the generating potential, the peak output capacity needs to be converted into the amount of electricity generated over time (in this case gigawatt hours per year).

72. The average annual electricity generation of a wind turbine can be

estimated by multiplying the installed capacity by the capacity factor12, then by multiplying that figure by the number of hours in a year (8760).

73. The average capacity factor for wind turbines in the UK is approximately

28%13. Taking the largest wind farms in Cornwall the average capacity factor is just over 26% (see Appendix 2). However, the wind farms that have been installed over recent years have a notably higher capacity factor. The wind farms that have been installed over the last 5 years achieve (on average) a capacity factor of just over 30%. Based on this marked improvement in efficiency the resource assessment has used an average capacity factor of just over 30%.

74. Using a 30% average capacity factor, the table below shows to total

annual electricity output potential from wind turbines in Cornwall.

Landscape Strategy

Landscapes with wind turbines

Landscapes with occasional wind

turbines Landscape Total Annual Electricity Output (GWhr/yr)

281.125 776.650

Combined Total Annual Electricity

1,057.775

12 The capacity factor is the ratio between average load and the installed capacity for a period of time (usually a year). 13 http://www.bwea.com/pdf/publications/RenewableUK_Turbine_Density_Study.pdf

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Output (GWhr/yr)

Table 2-9: Potential average annual electricity output from wind turbines in Cornwall

2.3 Results 75. 64% of the total area of Cornwall is considered to have an economically

viable wind resource (2272.15 km²). When this area subjected to technical and environmental/social constraints (not including landscape), the available land considered available for wind energy development is refined to a total of 234 km2 (6.5% of the area of Cornwall). With landscape character factored in this total area drops to 155 km² (4.4% of the area of Cornwall).

76. The table below summarises the potential average yearly electricity

generating capacity in Cornwall from wind energy development.

Potential constrained installed capacity (MW) 402.502

Average capacity factor of technology 0.3

Potential GWh per year 1,057.775

Potential energy production in thousands of tonnes of oil equivalent per year

90.95

Table 2-10: Summary of total average yearly electricity generation capacity potential from wind energy development in Cornwall

3.3 List of Layers

GIS Layer Category Source Wind speeds @ 10m Resource BERR/DECC Address Points Residential Cornwall Council Roads Transport

Infrastructure Cornwall Council

Railway Network Transport Infrastructure

Cornwall Council

33kV, 132kV Distribution Grid

Electricity Distribution Western Power Distribution

Rivers Geographical OS MasterMap Inland Waters Geographical OS MasterMap

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Special Protected Areas Environmental English Nature Special Areas of Conservation

Environmental English Nature


Environmental Natural England

World Heritages Sites Cultural Heritage Cornwall Council

Table 2-11: Summary of the GIS layers used in the wind assessment.

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3 Biomass – Energy Crops

3.1 Background

54. The definition of energy crops refers to crops which are grown specifically for energy production. The biomass is typically then combusted to heat water to produce steam for either electricity or heat production, or processed through a combined heat and power plant.

55. For the purposes of this assessment, energy crops considered were

Miscanthus and Short Rotational Coppice (SRC). The potential to harness biomass arising from forestry residue is assessed separately in chapter 4. The use of the term ‘biomass plant’ has been used to refer to a biomass-fuelled energy production facility, such as a boiler.

56. At the time of writing this report, there were no biomass plants in Cornwall

producing electricity. According to the ‘Regen SW Renewable Energy Progress Report: South West 2012 Annual Survey’14 there is an installed capacity of 19.843 MW of heat energy generation from biomass in Cornwall and the Isles of Scilly. However, this is predominantly from small scale woodchip or pellet boilers.

3.2 Methodology 57. In the case of the wind energy potential it is measured in terms of the size

and distribution of wind turbines (and the output of the installations). The assessment of the biomass potential, however, requires a different approach. Rather than attempt to identify potential sites for biomass plants, the assessment focussed on attempting to understand how much biomass fuel can be produced in Cornwall and, in turn, how much electricity and heat this might yield.

58. The biomass assessment was based on the sequential application of a

series of constraints to growing biomass fuel. These constraints were mapped using spatial GIS software to identify those areas that were unconstrained, i.e. available for the production of biomass fuel. The constraints were divided into three categories. These included resource, technical and environmental/social constraints. The constraints are summarised in the table below and are discussed in the following sections.

Resource Constraints Technical Constraints Environmental/Social

Constraints

14 http://regensw.s3.amazonaws.com/final_web_version_39857927b3496d43.pdf

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Only ALC grades 1, 2 and 3 are suitable for biomass growth Energy Content : Miscanthus – 17.3 GJ/tonne SRC – 18.6 GJ/tonne

Crops only grown on areas of arable land Miscanthus is the dominant crop SRC will be grown in areas where average wind speed is greater than 7m/s at 10m agl

Special Areas of Conservation (SAC) Special Protected Areas (SPA) Sites of Special Scientific Interest (SSSI) Scheduled Monuments (SM) World Heritage Sites (WHS) National Nature Reserves (NNR) Local Nature Reserves (LNR) Parks and Gardens Historic Battlefields No growth in areas of high landscape sensitivity to Biomass

Table 3-1: Summary of Constraints

59. The diagram below shows the process undertaken to assess the biomass

energy generation potential in Cornwall.

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Biomass Resource Assessment


Agricultural LandEnergy Content


Available land for crops

Identify the dominant crop for each area


Special Areas of Conservation

Special Protected Areas


Scheduled Monuments

World Heritage Sites


Local Nature Reserves

Parks and GardensHistoric Battlefields

Landscape Character

Convert the total yield (tonnes) into energy and

Convert the energy yield into gross capacity

Reduce the total to allow for other land uses in the unconstrained areas



Biomass Resource Assessment


Agricultural LandEnergy Content


Available land for crops

Identify the dominant crop for each area


Special Areas of Conservation

Special Protected Areas


Scheduled Monuments

World Heritage Sites


Local Nature Reserves

Parks and GardensHistoric Battlefields

Landscape Character



Reduce the total to allow for other land uses in the unconstrained areas



Figure 3-1: The biomass energy generation assessment process

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60. The Agricultural Land Classification (ALC) is the Department for

Environment, Food and Rural Affairs (DEFRA) system of classifying agricultural land quality. The quality of the land is based on characteristics, such as soil depth, structure, chemicals and stoniness. The classification divides the land into five grades with grade one being the highest quality and five being the lowest. The grade 3 band can be split into two sub grades called 3a and 3b. More information on the details of how the classifications are graded can be found on the DEFRA’s website15. It has been assumed that grades one to three, including sub grades 3a and 3b are suitable for the growing of biomass. The definition of grade four is ‘Poor Quality Agricultural Land: land with severe limitations which significantly restrict the range of crops and/or level of yields’.

61. In May 2007, DEFRA published the UK Biomass Strategy, which provides a

framework for the sustainable development of biomass for heat and power, transport fuels and industrial products. The strategy outlines EU and UK Government policies and explains how these operate to develop the use of biomass as a whole16. The strategy also quantifies the existing UK biomass resource and, more relevant to this assessment, the potential yields. It estimates that the potential yield for Miscanthus is 10-14 dte/ha (dry tonnes equivalent per hectare). For SRC, it estimates 6-10 dte/ha. When biomass is harvested the crop typically contains moisture. The moisture content of a feed stock to a biomass plant can significantly affect the plant’s production of energy. If the moisture content is too high, it needs to be dried. The assessment has estimated the potential yield in its dry tonne equivalent in order to eliminate the need to calculate the effect of moisture content when estimating the potential energy generation from biomass. Therefore in reality, it is conceivable that a single hectare of good quality agricultural land would produce more than, for example, 10-14 tonnes of Miscanthus.

62. The assessment has used a single yield figure to represent the dry tonne

equivalent yield per hectare for land within each ALC band. The highest yield within the estimated yield per hectare range was assigned to the best quality land (grade 1) and the lowest was applied to the grade 3 land. It was assumed that sub grades 3a and 3b provide the same crop yield as

15 Department for Environment, Food and Rural Affairs: Agricultural Land Classification information, [Online], Available: http://www.defra.gov.uk/foodfarm/landmanage/land-use/index.htm [06 Aug 09]. 16 Department of Energy and Climate Change, UK Biomass Strategy, [Online], Available: http://www.decc.gov.uk/en/content/cms/what_we_do/uk_supply/energy_mix/renewable/explained/bioenergy/policy_strat/policy_strat.aspx [24 Feb 10]

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grade 3. The potential crop yields for each grade are summarised in the table below.

Crop Yields (dte/ha/yr)

Agricultural Land Classification Miscanthus

Short Rotational Coppice

Grade 1 14 10 Grade 2 12 8 Grade 3 10 6

Table 3-2: Summary of Crop Yields Based on ALC

63. The UK Biomass Strategy also provided figures for the indicative energy

content of both Miscanthus and SRC. It states that the energy content of Miscanthus and SRC is 17.3 GJ/tonne and 18.6 GJ/tonne respectively.

64. The map below shows those areas of land which are considered suitable

for growing biomass crops, based on the ALC (grades 1 – 3). Areas of sub grades 3a and 3b are included within grade 3.


Figure 3-2: Map of Agricultural Land Classification

Technical Constraints 65. There are a number of limitations with the ALC in relation to its use as the

basis for determining suitable locations for growing biomass crops. The most significant for this study is that the ALC is high level and

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insufficiently detailed to filter out all the land that is not available for agricultural uses. For example, although urban areas were themselves a category within the classification system, not all urban land was removed. In order to mitigate these limitations, the assessment took steps to further refine the ALC dataset by filtering out those areas that are not available for growing crops.

66. In 1995, Cornwall County Council, in partnership with the Cornwall Wildlife

Trust, undertook to update of the complex land cover data sets across Cornwall17. The result was a detailed GIS map showing all arable land. Although the data is based on 1995 land coverage, it has been assumed that any changes to the land cover since then are not significant. For this purposes of this assessment the map of the arable land was combined with the ALC to refined the grade 1 – 3 agricultural land coverage and identify the locations of potential biomass growth.

67. It will be assumed that of the two crops considered in this assessment

Miscanthus will be the dominant crop choice. Despite SRC having a higher energy content, Miscanthus has a considerably higher yield, not just in terms of tonnes per hectare, but once established can be harvested every year. SRC can only be harvested every two to three years.

68. Recent studies, including both the ‘REvision 2010: Developing sub regional

renewable electricity targets for the SW’18 and ‘Plymouth Renewable Energy Strategic Viability Study’19 conclude that SRC is more suitable than Miscanthus in the more exposed locations. Areas too exposed for Miscanthus are defined by areas with a mean wind speed above 7m/s. Therefore, for the purposes of this assessment, it has been assumed that SRC will be grown in areas with a mean wind speed of 7m/s at 10m above ground level.

17 The Cornwall LIFE project. Funded by the European Commission’s LIFE fund. http://icaci.org/files/documents/ICC_proceedings/ICC1995/PDF/Cap102.pdf 18 ‘REvision 2010: Developing sub regional renewable electricity targets for the SW’ http://www.oursouthwest.com/revision2010/ 19 Plymouth Renewable Energy Strategic Viability Study’ http://www.google.co.uk/search?hl=en&safe=active&biw=1003&bih=592&q=Plymouth+Renewable+Energy+Strategic+Viability+Study%E2%80%99&btnG=Search&aq=f&aqi=&aql=&oq=

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Figure 3-3: Map of Arable Land and Wind Speeds greater than 7 m/s

69. The table below shows the available agricultural land within ALC grades 1 – 3 for each biomass fuel source.

Miscanthus SRC

ALC Grade Area (ha) Area (ha)

1 166.0 0 2 9,046.7 225.8 3 39,708.4 2,959.2

Total 48,921.1 3,185.0

Table 3-3: Summary of Yield Results based on the technical constraints

70. The map below illustrates the available agricultural land for both biomass fuel sources.

42

Figure 3-4: Map of suitable areas for biomass crops based in the technical constraints


Environmental/Social Constraints

71. The following designations were identified as constraints to growing

biomass crops in Cornwall: Special Areas of Conservation (SAC); Special Protected Areas (SPA); Sites of Special Scientific Interest (SSSI); Scheduled Monuments (SM); Historic Parks and Gardens; World Heritage Sites (WHS); National Nature Reserves (NNR); Local Nature Reserves (LNR).

72. While cultivating biomass crops in and around these areas may not

necessarily harm their integrity, it is likely that significant cultivation will. Consequently areas of land under these designations were excluded from the land available for biomass crop cultivation.

73. In 2004 Land Use Consultants and CAG Consultants prepared the ‘Cornwall

Sustainable Energy Project: Planning Guidance’ for Cornwall County Council and the Cornwall Sustainable Energy Partnership. The appendices of the report contain an assessment of the sensitivity of Cornwall’s

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Landscape Character Areas to biomass crops. Since the 2004 report, the Landscape Character Areas have been updated. However, no new re-assessment of their sensitivity to biomass crops has been done. Consequently, the 2004 sensitivity analysis has been used for this study. The assessment gives each character area a rating of sensitivity that ranges from low to high. For the purposes of this assessment the areas of highest sensitivity (those in the ‘high’ category) were considered constrained in terms of biomass crop cultivation due to the sensitivity of the landscape in those locations. These areas were discounted.

© Crown copyright. All rights reserved Cornwall Council, 100049047, 2011

Figure 3-5: Map of the environmental and social constraints

74. There are no formal restrictions on growing biomass crops in Areas of

Outstanding Natural Beauty or Heritage Coasts. The recently adopted Management Plan 20 produced by the Council’s AONB team recognises the potential for growing energy crops in the AONB, but stipulates that appropriate management needs to be in place to safeguard the character and biodiversity of these designated areas. Consequently, while sensitive landscapes were constrained in this assessment the AONB and Heritage Coast designations were not considered to be constraints to the cultivation of biomass crops.

75. The table below summarises the available land for each biomass types,

based on the technical and environmental constraints. The map (figure 3-

20 Cornwall Area of Outstanding Natural Beauty Management Plan 2011-2016. http://www.cornwall-aonb.gov.uk/management-plan/documents/ManagementPlanSection1.pdf

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6) shows the areas of land that were identified as being unconstrained and available for biomass crop cultivation.

Miscanthus SRC

ALC Grade Area (ha) Yield (dte/yr) Area (ha) Yield (dte/yr)

1 41.6 582.4 0 0 2 4,923.3 59,079.6 25.4 203.2 3 21,573.8 215,738 402.5 2,415

Total 26,538.7 275,400 427.9 2,618.2

Table 3-4: Summary of available land for biomass, based on the technical and environmental constraint


Figure 3-6: Map showing the available land for biomass, based on the technical and environmental constraint

76. In order to calculate the potential yield for each biomass fuel the total area

of land that is unconstrained was multiplied by the yield for (dry tonne equivalent). The total energy content of each biomass type was then calculated by multiplying the yield by the energy content.

77. The next step was to convert the energy content (in Gigajoules) into

delivered energy (Megawatts) by multiplying the energy content by the conversion factor. The conversion factor between Gigajoules and Megawatts in 0.277. This gives the potential installed capacity from each source of biomass in Cornwall.

45

78. In order to convert this figure into the amount of energy that is likely to be

produced in Cornwall over a year the following steps were undertaken:

1. Calculate how much gross energy can be delivered over a year (assuming the generation plants run at their installed capacity for that period). Gross annual capacity = available fuel each year (dte/year) x the energy content (for each biomass type) x the conversion factor (gigajoules into megawatts – 0.277) x the number of hours in a year (8760).

2. Biomass generation plants are not a hundred percent efficient so

factors must be applied to take account of the likely inefficiencies in converting the fuel into electricity and heat. For the purposes of this study it was assumed that the biomass generation plants were Combined Heat and Power (CHP) systems. A typical biomass CHP plant is approximately 80% efficient (i.e. 80% of the gross energy is converted into heat and electricity). Typically the net electrical capacity of a biomass CHP plants is approximately 24% and the net heat capacity is approximately 56% (of the gross capacity). These factors must be applied to calculate the likely net output from both biomass fuel sources over a year.

3.3 Results 79. The table below summarises the potential generation from biomass crops,

based on the assumption that 100% of the available land can be converted to growing the identified biomass crop.

Gross

Annual Available Energy

Gross Capacity

Net Electrical Capacity

Net Heat Capacity

Net Annual Energy

GWh MW MWe MWth GWh 1333.233 152.196 36.527 85.230 1,066.589

Table 3-5: Summary of Potential Generation from 100% of Available Land

80. While the assumption of 100% of all arable land being available for

biomass production would provide the maximum biomass potential, it would not be realistic. High quality agricultural land is required for other uses, such as food production. In the paper ‘REvision 2010: Developing sub regional renewable electricity targets for the SW’ 21 a 5% uptake of

21 ‘REvision 2010: Developing sub regional renewable electricity targets for the SW’ http://www.cse.org.uk/projects/view/1013

46

land is assumed. This assessment considered that 5% represents a figure that is likely to be achievable without leading to significant conflict with other land uses. The table below summarise the potential generation based on 5% of the available land unconstrained land being used for biomass.

Gross

Annual Available Energy

Gross Capacity

Net Electrical Capacity

Net Heat Capacity

Net Annual Energy

GWh MW MWe MWth GWh 66.661 7.61 1.824 4.261 53.331

Table 3-6: Summary of Potential Generation from 5% of Available Land

81. The table below summarises the potential average yearly electricity and

heat energy generating capacity in Cornwall from biomass energy crops.

Electricity Heat

Potential constrained installed capacity (MW) 1.824 4.261

Average capacity factor of technology 0.24 0.56

Potential GWh per year 15.978 37.326


1.374 3.209

Table 3-7: Summary of total average yearly electricity and heat generation capacity potential from biomass in Cornwall

3.4 List of Layers

GIS Layer Category Source Agricultural Land Classification Resource DEFRA Arable Land Resource Cornwall Council Wind Speed @ 10m Resource BERR Special Protected Areas Environmental English Nature Special Areas of Conservation Environmental English Nature Sites of Special Scientific Interest

Environmental Natural England

Scheduled Monuments Environmental English Heritage World Heritages Sites Environmental Cornwall Council National Nature Reserves Environmental English Nature Local Nature Reserves Environmental English Nature

47

Parks and Gardens Environmental English Heritage Historic Battlefields Environmental English Heritage Area of Outstanding National Beauty

Environmental Cornwall Council

Heritage Coast Environmental Cornwall Council 2004 Landscape Character Areas

Landscape Sensitivity

Cornwall Council

Table 3-8: Summary of the GIS layers used in the energy crop assessment

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4 Biomass - Forestry Residue and Waste Wood

4.1 Background 89. Forestry residue is the waste generated from the management of

woodland. This is produced from brashings and thrashings, toppings and loppings, thinnings etc.

90. For this assessment, forestry residue will be assumed to come from

existing woodland management only. Whilst some forestry in Cornwall may be felled for timber, it will be assumed that no wood in Cornwall will be diverted from its original purpose.

91. According to the Regen SW ‘Renewable Energy Progress Report: South

West 2012 Annual Survey’22 there is an installed capacity of 19.843 MW of heat from biomass in Cornwall and the Isles of Scilly. However, this capacity is predominantly provided by small scale woodchip or pellet boilers.

4.2 Methodology 92. The methodology for the assessment of the potential for generating

energy from forestry residue in Cornwall required a similar approach to that of biomass crops i.e. it was based on the yield of material from existing sources in Cornwall rather than the spatial distribution of potential biomass generation plants.

93. The forestry residue potential was estimated based on a simple GIS spatial

analysis. Unlike the assessment of the potential of other renewable energy sources and technologies no spatial constraints were to the resource. Instead, the total potential was calculated by multiplying the total area of forestry by a fixed yield. Once the total yield has been calculated, the potential energy production was then calculated using standard energy conversion factors.

94. By virtue of the fact that the resource is only considered to be the material

that is produced incidentally by ongoing woodland management, the application of environmental constraints is not necessary. The residue already exists and would simply be diverted to a new end process. There is no significant change to the woodland by collecting forestry residue and the management of woodland helps maintain the ecology of the woodland.


49

95. The diagram below shows the process undertaken to assess the forestry residue and waste wood (see section 4.5) energy generation potential in Cornwall.

Forestry Residue and Waste Wood

Forestry Residue

Identify areas of woodland Identify the yield (per hectare)

Remove areas considered too small

Identify collection boundaries

Waste Wood

Identify evidence of availability

Identify the waste streams that contain wood

Calculate the proportion of each stream that is wood

Compare with other evidence

Identify energy content





Forestry Residue and Waste Wood

Forestry Residue

Identify areas of woodland Identify the yield (per hectare)

Remove areas considered too small

Identify collection boundaries

Waste Wood

Identify evidence of availability

Identify the waste streams that contain wood

Calculate the proportion of each stream that is wood

Compare with other evidence

Identify energy content





Figure 4-1: The forestry residue and waste wood energy generation assessment process

4.3 Assumptions 96. For the purposes of this assessment it was decided that available resource

constitutes the forestry residue from Forestry Commission woodland and ancient semi-natural woodland.

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97. The report ‘REvision 2010: Developing sub regional renewable electricity

targets for the SW’23 adopted a similar approach and assumed that the sustainable woodland resource can only provide brashings associated with the ongoing management of the woodland. This report concluded that this results in a potential yield of 2dte/ha/yr (dry tonnes equivalent per hectare per year), regardless of type or size of woodland. This assumption has also been used in the ‘Plymouth Renewable Energy Strategic Viability Study’24 by the Centre for Sustainable Energy and ‘A Resource Audit and Market Survey of Renewable Energy Resource in Cornwall’ 25 by CSMA Consultants Ltd.

98. In order to assess what proportion of Cornwall’s total woodland is made up

of Forestry Commission woodland and ancient semi-natural woodland, the total resource needs to be identified. A report produced in 2001 for the Renewable Energy Office for Cornwall26 found that the majority of woodlands in Cornwall cover an area between 2 and 5 hectares. Therefore, for the purposes of this assessment all woodlands over 2 ha were considered available.

99. The GIS software MasterMap was used to analyse the woodland coverage

and identify that there are a total of 11,150 hectares of woodland greater than 2 hectares in Cornwall. The map below shows the location of all the woodland greater than 2 hectares.

23 REvision 2010: Developing sub regional renewable electricity targets for the SW’ http://www.cse.org.uk/projects/view/1013 24 Plymouth Renewable Energy Strategic Viability Study’ http://www.plymouth.gov.uk/070416,_plymouth_renewables_study_-_final_version_march_2007-2.pdf 25 A Resource Audit and Market Survey of Renewable Energy Resource in Cornwall’ http://www.reoc.info/files/reoc_pdf_complete_brochure_201207.pdf 26 A Resource Audit and Market Survey of Renewable Energy Resource in Cornwall’ CSMA, 2001. http://www.reoc.info/files/renewable_energy_resources_in_the_count_yof_cornwall.pdf

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Figure 4-2: Map of All Woodland greater than 2 hectares

100. Forestry Commission woodland and ancient semi-natural woodland make

up 74.2% of the total woodland in Cornwall. This means the total available resource is 8,273.5 ha and could produce an estimated 16,547 tonnes of forestry residue per annum.

101. The distribution of that resource is relevant to the scope to generate

energy from it. If the resource is dispersed then it may not be viable for it all to be collected and fed into generators. The maximum economic collection radius is considered to be around 40 km from the generation plant. In Cornwall a centralised biomass plant located near to Bodmin would be able to utilise approximately 92% of the total available resource in Cornwall. It is acknowledged that alternatives to a single centralised generation plant may be deployed, but it is likely to be difficult to make use of 100% of the resource. For the purposes of this assessment it was considered reasonable to assume that 92% of the available resource can reasonably be accessed and used to generate energy.

102. The most recent publicly available analysis of the potential energy yield

from forestry residue was undertaken in 2010. The report, entitled ‘Analysis of biomass residues potential for electrical energy generation in Albania’ suggested that the energy content of forestry residue is 16.6

52

GJ/tonne27. For the purposes of this assessment the figure of 16.6GJ/tonne provided the basis for the energy conversion.

103. Once the total forestry residue yield has been estimated, the potential

generation from forestry residue can be calculated from the following equation:

Gross Capacity (MW) = Yield (dte/ha/yr) x Energy Content (GJ) x the Conversion factor (GJ to MW (0.277)) / the number of hours in a year (8760).

104. In order to calculate the net capacity (i.e. the amount of energy that is

likely to be generated from the fuel taking into account losses in the generation process), a conversion factor of approximately 0.24 must be applied for electricity and 0.56 for heat (based on typical biomass CHP systems with a combined efficiency of 80%).

4.4 Results 105. The table below summarises that potential generation from forestry

residue in Cornwall (based on 92% of the resource being used).

Total Total Yield (tonnes) 15,223 Total energy content (GJ) 252,701.8 Total Available Annual Energy (GWh) 69.998 Gross Capacity (MW) 7.99 Net Electrical Capacity (MW) 1.918 Net Heat Capacity (MW) 4.474 Net Annual Electricity (GWh) 16.802 Net Annual Heat (GWh) 39.192

Table 4-1: Summary of Forestry Residue Energy Generation Potential in Cornwall

106. Typically, the heat output from a centralised CHP plant is greater than the

electrical output. With that in mind a centralised CHP plant would need sufficient heat consumers in close proximity to make use of the heat. If sufficient demand for heat cannot be identified in the vicinity of a centralised plant it may be more appropriate that the forestry residue be

27 Karaj, Sh. Rehl, T. Leis, H. & Muller, J. (2010) ‘Analysis of biomass residue potential for electrical energy generation in Albania’, Renewable and Sustainable Energy Reviews, vol. 14, issue 1, January, pp. 493-499.

53

used at a community scale to supply heat and power to a number of communities.

107. According to the UK Biomass Energy Centre, a 100kW woodchip boiler

running at an efficiency of 85% (heat only) for 10 hours a day for 7 days would require 1.7 tonnes of woodchip. That equates to between 88.4 tonnes per annum. This approach would enable 343 small scale community heating systems. Based on heat only boilers that overall potential installed capacity would be 34.4 MWth. This would provide 7.7 times more heat than if a centralised biomass CHP system, with a focus on electrical generation.

4.5 Waste Wood 108. Waste wood is wood that is reclaimed, such as old pallets or residue from

saw mills, and processed into woodchip. This resource is difficult to quantify and the quality of the wood affects the potential to generate energy and sustain the generation (maintain the generation plants).

109. The potential to generate electricity and heat from waste wood has not

been formally examined as part of this assessment. This was primarily due to the lack of information available on the amount of waste wood in Cornwall and where it arises. However, based on the information available this assessment has included an approximate estimation of the potential for waste wood electricity and heat generation. In 2010, the Council was advised that 26,000 tonnes per annum of waste wood could readily be available as woodchip for combined heat and power projects28.

110. Data on waste arisings for the Commercial and Industrial waste stream in

Cornwall suggests that approximately 25,000 tonnes of waste classified as textiles, paper and waste wood arose in 2009. This figure equates to approximately 7% of the total arisings in that year. The Commercial and Industrial waste stream is broadly similar in mix to the Municipal waste stream (Local Authority Collected Waste). It is therefore assumed that a similar proportion of the arisings would be textiles, paper and wood. In 2009, approximately 306,000 tonnes of Municipal waste arose. 7% of that figure would give approximately 21,500 tonnes. The total textiles, paper and wood waste arising in Cornwall could be estimated at approximately 46,500 tonnes (based on 2009 arisings data).

111. Based on the information available it is not possible to extract the exact

proportion of the waste classified as textiles, paper and wood that is wood waste. However, the waste data for 2009 indicates that a figure of 26,000

28 Personal Communication with Adrian Lea, Cornwall Council, on 22nd January 2010

54

tonnes per year is not unreasonable. For the purposes of this study this figure (26,000 tonnes per year) is considered to represent the approximate wood waste resource for Cornwall.

112. This is a significant resource and should be included with the forestry

residue to enhance the potential biomass resource. 113. Assuming that the waste wood as chip has the same energy content as

forestry residue, 26,000 tonnes of waste wood would provide an extra 13.65 MW in gross power output. This would equate to an extra 3.276 MWe and 7.644 MWth in net electrical and heat capacity, respectively.

4.6 Summary 114. Table 4-2 summarises the total potential generation from forestry residue

for the total available resource, the resource within 40km of a biomass plant and the enhanced potential from the waste wood resource.

Total Total Wood

Resource (incl. Waste Wood)

Total Yield (tonnes) 15,223 41,223 Gross Capacity (MW) 8.7 21.64 Net Electrical Capacity (MW) 2.1 5.194 Net Heat Capacity (MW) 4.9 12.118 Net Annual Electricity (GWh) 16.802 45.499 Net Annual Heat (GWh) 39.192 106.154

Table 4-2: Summary of Total Forestry Residue Potential

115. The electrical output, based on the resource within the 40km collection

radius and the waste wood, could support a centralised plant. Equally, the resource could support an even wider range of community schemes. However, the aim of this report is to assess the resource potential and not to determine how the resource could be utilised to provide the greatest benefit to the county. The table below summarises the potential average yearly electricity and heat energy generation capacity in Cornwall from forestry residue and waste wood.

Electricity Heat

Potential constrained installed capacity (MW) 5.194 12.118

Average capacity factor of technology 0.24 0.56

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Potential GWh per year 45.499 106.154


3.912 9.128

Table 4-3: Summary of total average yearly electricity and heat generation capacity potential from biomass in Cornwall

4.7 List of Layers

GIS Layer Category Source Woodland, area greater than 2ha

Resource OS MasterMap

Forestry Commission Woodland Resource Forestry Commission

Ancient Semi-Natural Woodland Resource Forestry Commission

Table 4-4: Summary of the GIS layers used in the forestry residue assessment

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5 Waste

5.1 Background 116. Energy recovery is the process of recovering the energy content within

waste using a variety of technologies. There are currently four main technologies for energy recovery: energy from waste (EfW), anaerobic digestion (AD), gasification and pyrolysis.

117. An EfW facility works by combusting the waste at high temperatures. Heat

released from the combustion process produces steam by heating water in a heat exchanger which, in turn, drives a steam turbine to produce electricity. Waste heat can also be recovered to make the process a combined heat and power facility.

118. Anaerobic digestion uses bacteria to break down organic materials in the

absence of oxygen. This process results in the production of biogas which can be combusted to generate electricity and heat.

119. Gasification is the process whereby waste is heated and combined with

steam and oxygen to produce what is commonly referred to as syngas. Syngas is a mixture of carbon monoxide and hydrogen which can be combusted to generate electricity and heat.

120. Pyrolysis is the process whereby waste is heated in the absence of oxygen

to produce char and gas. The gas can then be processed and combusted to produce electricity and heat. At present, while pyrolysis is based on a well understood concept, it is not yet widely used for energy recovery from waste in the UK. Consequently, the amount of information upon which to base an assessment of its potential is limited. It is not unreasonable to assume that it will play a significant role in waste management in the future, but the lack of detailed information about system requirements and performance in the UK means that it has not been included in this assessment. This omission does not have a bearing on the overall outcome of this assessment, because the aim of the assessment was to provide a reasonable indication of the potential to derive energy from waste in Cornwall, rather than an absolute figure for all conceivable technologies and scenarios.

121. This study considered the broad potential to recover waste from the two

main mixed waste streams in Cornwall: Local Authority Collected Municipal Waste (Municipal) and Commercial and Industrial Waste (C&I). These waste streams account for the vast majority of waste arising in Cornwall

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from which energy can be readily released. Waste arisings figures29 indicate that 304,386 tonnes of Municipal waste and 351,380 C&I tonnes arose in 2010/11. The waste arising in these waste streams has been referred to as ‘mixed waste’ in this section.

122. According to the 2011 South West Annual Survey for renewable energy,

produced by Regen SW30 there is no advanced treatment of waste producing electricity or heat (energy recovery) in Cornwall at present.

5.1 Methodology 123. The diagram below shows the process undertaken to assess the waste

energy generation potential in Cornwall.

29 An Assessment of the Future Waste Arisings in Cornwall up to 2031 (Cornwall Council, 2012) 30 Renewable Energy Progress Report: South West 2011 Annual Survey (Regen SW, 2011) http://regensw.s3.amazonaws.com/regen_2011_survey_web_7dc475ef5cb3b5d3.pdf

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Waste Resource Assessment

Identify reasonable energy recovery scenarios (reflecting the available recovery technologies)

Identify the total mixed waste arising each year in Cornwall

Understand the likely maximum proportion that will be recycled

Define the proportion of the remaining waste that is recoverable by each energy recovery technology

Identify the energy content and likely yield for each scenario

Convert the total output into gross and net energy generation capacity

Convert the total installed capacity into annual generation (GWh) and thousand tonnes of oil equivalent.

Waste Resource Assessment

Identify reasonable energy recovery scenarios (reflecting the available recovery technologies)

Identify the total mixed waste arising each year in Cornwall

Understand the likely maximum proportion that will be recycled

Define the proportion of the remaining waste that is recoverable by each energy recovery technology

Identify the energy content and likely yield for each scenario



Figure 5-1: The waste energy generation assessment process

Resource Constraints 124. A spatial analysis of the potential resource, such as the one undertaken for

the wind resource, is not appropriate for assessing the energy potential within the waste that arises in Cornwall, due to the way waste is produced and managed. Waste is collected from homes and businesses and taken to processing facilities for sorting. Some of the waste is recycled, some sent to landfill and some used to recover energy. A statistical analysis of the potential energy generation capacity is therefore more appropriate in this case.

125. Cornwall Council’s technical report ‘An Assessment of the Future Waste

Arisings in Cornwall up to 2030’ has been used as the primary source of data for waste arisings projections and the amount of waste that is likely to be available for energy recovery. The report provides historic waste

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arisings data for each of the main waste streams in Cornwall and makes projections for the future arisings up to 2030.

126. Due to the range of available energy recovery technologies there are a

number of possible energy recovery scenarios for Cornwall. This assessment has not attempted to determine which technology, or technologies, will be used to recover energy from waste in Cornwall in the future. Instead, a range of scenarios were developed to represent the feasible energy recovery opportunities in the medium term in order to give an indication of the potential for energy generation from the waste that arises in Cornwall.

127. The available energy performance data is not consistent across the

difference energy recovery technologies. Consequently, where necessary, the energy generation potential of each technology has been calculated using a combination of technical data and informed assumptions.

128. The following energy recovery technology scenarios were chosen to

represent the likely scope of energy generation from our mixed waste:

1. All residual mixed waste (that is not recycled or re-used) is processed through energy from waste;

2. All digestible mixed waste is processed through anaerobic digestion with the remainder (that is not recycled or re-used) processed through Energy from Waste;

3. All residual mixed waste (that is not recycled or re-used) is processed through gasification.

129. The indicative output from each scenario was modelled using one facility

for each technology which processes all the waste available to it. In reality it is possible that a number of facilities might be built across Cornwall. While individual operating parameters may vary between a single facility and multiple facilities, the total tonnage processed would remain constant. For the purposes of this assessment it was therefore considered reasonable to model a single facility for each technology.

130. The individual components of each scenario are explained in the feedstock

assumptions section below.

Technical Constraints - Feedstock Assumptions

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131. In order to set the basis for compliance with Government waste management policy31 and to help meet the Government’s 2020 greenhouse gas emissions commitments the report ‘An Assessment of the Future Waste Arisings in Cornwall up to 2030’ includes projected recycling/re-use levels that are expected to be met in Cornwall by 2020. These levels include achieving 50% recycling/re-use of the Municipal waste stream and 65% recycling/re-use of the C&l waste stream. For the purposes of this assessment it has therefore been assumed that the proportion of the mixed waste arising in Cornwall that has potential to be used to recover energy is the waste that remains after these recycling/re-use levels are met.

132. The total mixed waste arsings in 2020 are expected to be approximately

677,000 tonnes, made up of 298,545 tonnes of Municipal waste and 378,461 tonnes of C&I waste. Based on the projected re-use/recycle proportion of approximately 58% of the total mixed waste the residual waste that will be available for energy recovery in 2020 is 281,734 tonnes, made up of 149,273 tonnes of Municipal waste and 132,461 tonnes of C&I waste.

133. Based on this analysis it has been assumed that 281,734 tonnes of mixed

waste constitutes the annual waste resource potential in Cornwall in terms of energy generation. In reality, the amount of waste produced each year varies depending on a number of factors and is unlikely to remain exactly 677,000 each year from 2020. However, dramatic year on year changes are not anticipated.

134. For the purposes of this assessment it has been assumed that all residual

municipal (Local Authority Collected Waste) waste is suitable for processing by energy from waste and gasification facilities. In the case of anaerobic digestion, which is the breakdown of organic materials, it has been assumed that only the putrescible proportion of the waste stream is suitable. Data collected as part of the 2007 Cornwall Kerbside Residual Composition Analysis indicates that putrescible waste accounts for 44.23% of the total Municipal waste stream. Under the anaerobic digestion scenario (Scenario 2) it was assumed that the putrescible elements of the municipal waste stream will remain after it has been sorted for recycling and re-use. It has also been assumed that all of the residual putrescible waste is sent to anaerobic digestion with any remaining residual waste going to energy from waste.

135. The main components of C&I waste streams that are suitable for energy

recovery are the animal & plant, sludge and ‘mixed’ waste categories.

31 National Waste Strategy for England 2007. http://archive.defra.gov.uk/environment/waste/strategy/strategy07/documents/waste07-strategy.pdf

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Combined, these three components made up 47% of the total C&I waste stream in 200932. All three components can be processed by energy from waste and gasification technologies, but only the animal, plant and sludge components are suitable for anaerobic digestion. This digestible proportion makes up 17% of the total C&I waste stream. For the purposes of this assessment it was assumed that these proportions will remain constant in the future.

136. Under the anaerobic digestion scenario (Scenario 2) approximately 55% of

the total residual mixed waste (Municipal and C&I combined) after recycling/re-use (154,564 tonnes) will be available for anaerobic digestion (with the remainder going to energy from waste).

Technical Constraints - Technological Assumptions 137. The output efficiency of the energy from waste facility modelled for this

assessment was calculated by multiplying the typical electrical conversion of a conventional steam boiler with the capacity factor of the facility. The electrical conversion efficiency of a conventional steam boiler is typically 30%. Assuming that the facility is running for 80% of the year, the overall conversion efficiency would be 24%. Both the Institute of Mechanical Engineers (IMechE)33 and DEFRA34 quote that the conversion efficiency of an energy from waste facility is 20-25%. The calculated figure of 24% is within the range quoted by the IMechE and DEFRA and has therefore been included as the output efficiency for energy from waste facilities in this assessment.

138. The conversion efficiency for an anaerobic digestion plant was calculated in

the same way. The assumed electrical conversion efficiency was 30%. However, as digesters can vary between batch and continuous loads, it was assumed that it will run for 70% of the year. This gives a conversion efficiency of 21%. Aashish Mehta, of the Department of Agricultural and Applied Economics Energy Analysis and Policy Program for the University of Wisconsin, produced a paper titled ‘The Economics and Feasibility of Electricity Generation using Manure Digesters on Small and Mid-size Dairy Farms’. The paper assumes that for the digester the efficiency of a

32 Commercial and Industrial Waste Survey 2009 Final Report. Defra, 2010. 33 Institute of Mechanical Engineers: Energy From Waste A Wasted Opportunity, [Online], Available: http://www.imeche.org/about/keythemes/environment/Reducing+Reusing+and+Recycling/Energy+from+Waste/ [20 Oct 09] 34 Department for Environment, Food and Rural Affairs: Waste Infrastructure Delivery Programme Information Note on Combined Heat and Power, [Online], Available: http://www.defra.gov.uk/environment/waste/residual/widp/index.htm [20 Oct 09]

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standard heat engine and generator is 21%35. Furthermore, a publication by the National Sustainable Agricultural Information Service entitled ‘Anaerobic Digestion of Wastes: Factors to Consider’ assumes a generating efficiency of 20%. Therefore, the calculated figure of 21% was considered reasonable and has been included as the output efficiency for anaerobic digestion facilities in this assessment.

139. The conversion efficiency for gasification is calculated from the product

information for the Energos Type-41 gasification plant with an electrical output of 3.1MW36. The calculation is based on the maximum nominal operating margin assuming an energy content of 11.75 GJ/tonne and a fuel consumption rate of 5 tonnes/hr. Based on these figures, the electrical conversion efficiency is 19%. Due to the absence of a broader range of energy efficiency information for gasification plants in the UK this figure has been included in the assessment.

Technology Conversion

Efficiency EfW 24% AD 21%

Gasification 19%

Table 5-1: Summary of Technological Conversion Efficiencies

140. The average energy content of mixed waste is approximately 9 GJ/tonne37.

This figure has been included in this assessment as the basis for calculating the potential energy yield from energy from waste. However, both anaerobic digestion and gasification differ from energy from waste facilities in that their processes convert the waste into a new type of fuel, (syngas in gasification and biogas in anaerobic digestion). An anaerobic digester can produce a biogas yield of 46 m3/tonne from food processing waste, with an average energy content of 23 MJ/m3 (38).

141. Although gasification converts the waste into a syngas, the energy content

of 9 GJ/tonne (the average energy content associated with mixed waste) was also used for gasification. With anaerobic digestion, some of the energy released is consumed by the system in order to maintain

35 The Economics and Feasibility of Electricity Generation using Manure Digesters on Small and Mid-size Dairy Farms, [Online], Available: http://www.mrec.org/pubs/Biogas_Economics_Metha.pdf [20 Oct 09] 36 Energos: Type-41 Gasification Plant, [Online], Available: http://www.energ.co.uk/capacity_diagram [17 Aug 09] 37 Climate Change 2007: Working Group III: Mitigation of Climate Change http://www.ipcc.ch/publications_and_data/ar4/wg3/en/ch10s10-1.html 38 Anaerobic Digestion of farm and food processing residues Good Practice Guidelines, [Online], Available: http://www.mrec.org/biogas/adgpg.pdf [23 Nov 09]

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conditions for the process. During the gasification process the syngas is produced through the reduction in the mass of the waste which has the effect of increasing the energy content. However, the overall energy released by the end of the process remains the same.

142. In all cases a combined overall efficiency for combined heat and power of

80% was used. However, this efficiency factor does not explicitly include an allowance for heat and power that might be used during the process.

143. The following steps were undertaken to calculate the energy output from

each technology:

1. Calculate the total gross energy potential (gigajoules): 2. Total tonnage available for each process (tonnes) x energy yield

(gigajoules) = total gross energy potential (gigajoules).

3. Convert it into total gross energy capacity (in megawatts): Total gross energy potential (GJ) x the number of MW produced by a GJ (0.277 MW) = gross energy capacity (megawatts).

4. Convert the gross capacity into gross annual output: Gross capacity

(MW) x number of hours in a year (8760).

5. Factor in the typical annual operational ‘downtime’ for each facility (20% for EfW, 30% for AD, gasification assumes an overall 19% electrical efficiency which includes operational downtime)

6. Factor in the efficiency factors for electricity and heat generation: 7. Electricity: Total gross ‘installed’ energy capacity / 100 x combined

heat and power efficiency (80%) x electrical energy efficiency figure = net electricity capacity (MW).

8. Heat: Total gross ‘installed’ energy capacity / 100 x combined heat and power efficiency (80%) – electricity capacity = net heat energy capacity (MW).

5.3 Results 144. The results of the analysis are summarised below in the tables below.

Scenario 1: All residual waste to Energy from Waste

Annual Tonnage (tonnes/yr) 281,734

Energy Content (GJ/tonne) 9

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Gross Annual Energy Capacity (GJ/yr) 2,535,606

Gross Annual Energy Capacity (MWh/yr) 704,898

Installed Energy Capacity (MW) 80.47

Net Electricity Capacity (MW) 24.14

Net Heat Capacity (MW) 40.2

Net Annual Electricity Output (based on 80% annual operation) (MWh/yr)

169,173


281,721

Table 5-2: Energy generation potential from Energy from Waste

Scenario 2: All digestible waste to

Anaerobic Digestion and remainder to Energy from Waste

AD EfW

Annual Tonnage (tonnes/yr) 154,564 127,170

Energy Content (GJ/tonne) 1.058 9

Gross Annual Energy Capacity (GJ/yr) 163,529 1,144,530

Gross Annual Energy Capacity (MWh/yr) 45,461 318,179

Net Installed Energy Capacity (MW) 3.6 36.3

Net Electricity Capacity (MW) 1.1 10.9

Net Heat Capacity (MW) 1.8 18.2

Annual Electricity Output (based on 100% annual operation) (MWh/yr)

9,636 76,387.2

Annual Electricity Output (based on 100% annual operation) (MWh/yr)

15,768 127,545.6

Combined Annual Electricity Output (MWh/yr)

86,023.2

Combined Annual Heat Output (MWh/yr) 143,313

Table 5-3: Energy generation potential from Anaerobic Digestion and Energy from Waste

Scenario 3: All residual waste to Gasification

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Annual Tonnage (tonnes/yr) 281,734

Energy Content (GJ/tonne) 9

Gross Annual Energy Capacity (GJ/yr) 2,535,606

Gross Annual Energy Capacity (MWh/yr) 704,898

Installed Energy Capacity (MW) 80.47

Net Electricity Capacity (MW) 15.3

Net Heat Capacity (MW) 49.1


134,028


430,113

Table 5-4: Energy generation potential from Gasification

145. The results show that Scenario 1 (the energy from waste scenario) has the

potential to yield the greatest amount of renewable energy – approximately 170 gigwatt hours of electricity and 280 gigwatt hours of heat each year.

146. While the output varied for each scenario, they are all valid as an indication

of the potential energy output from waste arising in Cornwall. This report, therefore, presents the indicative energy output as a range, using the lowest output (Scenario 2) and the highest (Scenario 1).

147. The table below summarises the total average yearly electricity and heat

generation capacity potential from waste arising in Cornwall.

Electricity Heat

Potential constrained installed capacity (MW) 12 - 24.14 20 - 40.2

Potential GWh per year 86 – 169.2 143.3 - 281.7


7.39 - 14.55 12.32 - 24.28

Table 5-5: Summary of total average yearly electricity and heat generation capacity potential from waste in Cornwall

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6 Livestock Slurry

6.1 Background 148. Slurry is the mixture of water and the waste produced by livestock. For this

assessment, the production of slurry was assumed to have arisen from cattle, pigs and poultry.

149. At present, slurry is typically diluted and/or treated so that it can be spread

on agricultural land as a fertiliser. However, it can also be treated in an anaerobic digester. This assessment estimated the potential for livestock slurry to be used to produce energy through anaerobic digestion in Cornwall.

150. According to the Regen SW ‘Renewable Energy Progress Report: South

West 2012 Annual Survey’39 there is currently no treatment of slurry producing renewable electricity or heat in Cornwall.

6.2 Methodology 151. As in the assessment of energy recovery from waste (chapter 5), the live

stock slurry assessment was based on a statistical analysis. The potential was calculated based on the energy production from biogas. The total biogas production was calculated from how much slurry each animal produces, for each type of livestock, and how much biogas can be produced from each stream of slurry.

152. The diagram below show the process undertaken to assess the livestock

slurry energy resource potential for Cornwall.


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Livestock Slurry Resource Assessment

Identify key slurry producers and determine their average daily slurry production


Reduce this figure to take account of competing uses for the slurry (e.g. manure)


Livestock Slurry Resource Assessment

Identify key slurry producers and determine their average daily slurry production


Reduce this figure to take account of competing uses for the slurry (e.g. manure)


Figure 6-1: The livestock slurry energy generation potential process

153. The daily methane yield can be converted into a gross energy potential in

megawatts using the following calculation:

Methane Yield (tonnes/day) x Number of megajoules per tonne x the conversion factor (converting megajoules to kilowatts (0.277)) = kilowatts of energy potential produced by all the livestock each day.

154. This figure can then be divided by the number of hours in a day and then

further divided by 1000 to give the energy potential from all livestock in megawatts. To convert this energy capacity into annual delivered energy capacity it needs to be multiplied by 8670 (hours per year).

155. A 70% capacity factor has been used to calculate energy loss during

refinement. This provides an energy yield. Typically, a biogas CHP plant will by 70% efficient with, typically, 30% produced as electricity and the remainder as heat.

6.3 Assumptions 156. The majority of the assumptions needed for calculating the slurry potential

can be found in the report ‘Anaerobic Digestion of Farm and Food Processing Residues: The Development of a Sustainable Industry: Good

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Practice Guidelines’40. The guidelines outline the slurry production, the biogas yield and the energy content for all three types of livestock. The data is summarised in the table below:

Slurry Production per Animal (tonne/day)

Energy Content (MJ/m3)

Livestock

Min Max

Biogas Yield (m3/tonne)

min Max Cattle 0.025 0.05 25 23 25 Pigs 0.0033 0.004 26 21 25 Poultry 0.00011 0.000125 120 23 27

Table 6-1: Summary of Slurry Production

157. The main source of data for the total population of livestock in Cornwall is

from DEFRA’s June 2008 ‘Agricultural and Horticultural Survey of England’41. The results of the survey are summarised below:

Livestock Population Cattle 340,451 Pigs 53,695 Poultry 1,397,654

Table 6-2: Summary of Livestock Population

6.4 Results

Total Potential

158. The good practice guidelines provide a range of slurry production and energy content for each type of livestock. Consequently this assessment has calculated both the minimum and maximum potential energy yield from livestock in Cornwall. The minimum potential was based on the minimum slurry production and energy content. The maximum potential was based on the maximum slurry production and energy content. The minimum and maximum potential is summarised in Tables 6-3 and 6-4, respectively.

Livestock Total Dry Biogas Gross Net Net Net Net

40 Anaerobic Digestion of Farm and Food Processing Residues: The Development of a Sustainable Industry: Good Practice Guidelines http://www.sharedpractice.org.uk/Downloads/Energy%20from%20anaerobic%20digestion.pdf, British Biogen, London. 41 DEFRA’s June 2008 Agricultural and Horticultural Survey of England http://data.gov.uk/dataset/june-survey-of-agriculture-and-horticulture-2008

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Weight of Slurry (tonnes/ day)

Yield (m3/ day)

Capacity (MW)

Heat Capacity (MWth)

Annual Heat (GWh)

Electrical Capacity (MW)

Annual Electricity (GWh)

Cattle 8511.3 212782.1 56.48 - - 11.86 103.91 Pigs 177.2 4607.1 1.12 - - 0.23 2.05 Poultry 153.7 18449.0 4.90 - - 1.03 9.01 Total - - 62.50 30.625 268.275 13.12 114.97

Table 6-3: Summary of the minimum total potential

Livestock Total

Dry Weight of Slurry (tonnes/ day)

Biogas Yield (m3/ day)

Gross Capacity (MW)

Net Heat Capacity (MWth)

Net Annual Heat (GWh)

Net Electrical Capacity (MW)

Net Annual Electricity (GWh)

Cattle 17022.6 425564.2 122.79 - - 25.79 225.89 Pigs 214.8 5584.3 1.61 - - 0.34 2.96 Poultry 174.7 20964.8 6.53 - - 1.37 12.02 Total - - 130.94 64.1606 562.0467 27.50 240.87

Table 6-4: Summary of the maximum total potential

20% of Population

159. There are a number of limitations associated with the assumption that all

slurry production can be processed through a centralised anaerobic digester. While it would yield the maximum potential, it would not be practical. Firstly, it is not likely that it would be financially viable to process all the slurry in a centralised facility. Secondly, as slurry is typically spread on agricultural fields as an alternative to inorganic fertilisers, some farmers may not be willing to change their method of dealing with slurry, given that it provides them with a resource.

160. In the report ‘A Resource Audit and Market Survey of Renewable Energy

Resource in Cornwall’42 it is estimated that 20% of the livestock would be available for anaerobic digestion. For the purposes of this assessment 20% was considered a reasonable figure. Therefore, based on an availability of 20%, the minimum and maximum potential is summarised in the tables below.

Livestock Total Biogas Gross Net Net Net Net

42 A Resource Audit and Market Survey of Renewable Energy Resource in Cornwall’ http://www.reoc.info/files/reoc_pdf_complete_brochure_201207.pdf

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Yield (m3/ day)

Capacity (MW)

Heat Capacity (MWth)

Annual Heat (GWh)

Electrical Capacity (MW)

Annual Electricity (GWh)

Cattle 1702.3 42556.4 11.30 5.537 48.50 2.37 20.78 Pigs 35.4 921.4 0.22 0.108 0.946 0.05 0.41 Poultry 30.7 3689.8 0.98 0.48 4.20 0.21 1.80 Total - - 12.50 6.125 53.665 2.62 22.99

Table 6-5: Summary of minimum available potential

Livestock Total


Biogas Yield (m3/ day)

Gross Capacity (MW)

Net Heat Capacity (MWth)

Net Annual Heat (GWh)

Net Electrical Capacity (MW)

Net Annual Electricity (GWh)

Cattle 3404.5 85112.8 24.56 12.034 105.42 5.16 45.18 Pigs 43.0 1116.9 0.32 0.16 1.40 0.07 0.59 Poultry 34.9 4193.0 1.31 0.84 7.36 0.27 2.40 Total - - 26.19 12.833 112.41 5.50 48.17

Table 6-6: Summary of maximum available potential

161. The table below summarises the total average yearly electricity and heat

generation capacity potential from livestock slurry arising in Cornwall.

Electricity Heat

Potential constrained installed capacity (MW) 2.62 – 5.55 6.28 – 13.16

Average capacity factor 0.7 & 0.3 0.7 & 0.7

Potential GWh per year 22.95 – 48.618

55.024 – 115.29


1.97 – 4.18 4.73 – 9.913

Table 6-7: Summary of total average yearly electricity and heat generation capacity potential from livestock slurry in Cornwall

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7 Hydropower

7.1 Background 162. Hydropower is energy harnessed from flowing water. Hydropower

technology has been in use for thousands of years with the earliest examples being the Greeks who used water wheels to grind grain.

163. According to the ‘2012 Renewable Energy Progress Report: South West

2012 Annual Survey’ produced by Regen SW43 of renewable electricity and heat projects in South West England’ there is 1.696 MW of hydro electric power installed in Cornwall and the Isles of Scilly.

7.2 Methodology 164. The diagram below shows the process undertaken to assess the

hydropower potential in Cornwall.

Hydropower Resource Assessment

Identify the potential capacity of hydropower sites in Cornwall (based on Environment Agency assessment)

Define the total output from sites within ach sensitivity band and remove those sites within the ‘high’ sensitivity band



Hydropower Resource Assessment

Identify the potential capacity of hydropower sites in Cornwall (based on Environment Agency assessment)

Define the total output from sites within ach sensitivity band and remove those sites within the ‘high’ sensitivity band



Figure 7-1: The hydropower resource assessment process


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165. The Environment Agency has undertaken an assessment of the potential hydropower resource in Cornwall as part of a wider assessment of England and Wales44. The assessment estimates and maps the available resource potential for hydropower generation in Cornwall using basic environmental sensitivity constraints. The main constraints used were the probability of migratory fish species in river systems and the presents of the Special Areas of Conservation (SAC) designation.

166. The resource potential was calculated through the assessment of river

height and flow data. Sites with sufficient drop (height) to provide a hydropower opportunity were made up primarily of weirs and other man-made structures with some natural features such as waterfalls. Estimates of river flow rates at each site were based on the Environment Agency datasets and gauging stations.

7.3 Results 167. The results identified that small scale hydropower opportunities provide

the principal resource in Cornwall, with calculated potential power outputs per site ranging from 0 – 530 kW. The majority of these sites fell within the 0 – 10 kW and 10 – 50 kW scales. The report also concluded that a large proportion of the sites identified in Cornwall have high environmental constraints.

Environmental Sensitivity Combined Potential Capacity Low Environmental Sensitivity 136 kW Medium Environmental Sensitivity 122 kW High Environmental Sensitivity 4925kW

Table 7-1: The estimated output from hydropower sites based on their level of sensitivity.

44 ‘Opportunity and environmental sensitivity mapping for hydropower in England and Wales’ http://publications.environment-agency.gov.uk/PDF/GEHO0310BRYF-E-E.pdf

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Figure 7-2: Sites for hydropower in Cornwall based on their potential installed capacity.

168. Within Cornwall the study identified a combined potential of 136 kW for

sites with a low environmental sensitivity and 122 kW with a medium sensitivity. A large amount of sites identified (4,925 kW) fall in high environmental sensitivity category and were therefore considered unlikely to be brought forward. It was therefore considered that, for the purposes of this assessment, an appropriate potential capacity in Cornwall for hydropower is the combined potential capacity for low and medium environmental sensitivity sites of 258 kW. With the existing hydropower schemes added to this figure Cornwall’s total resource for is estimated to be 1,954 kW (1.954 MW).

169. The table below summarises the total average yearly electricity generation

capacity potential from hydropower resources in Cornwall.

Electricity Yield


Average capacity factor 0.6

Potential GWh per year 10.270

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0.883

Table 7-2: Summary of total average yearly electricity generation capacity potential from hydroelectricity installations in Cornwall

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8 Solar Resource

8.1 Background 170. Energy from the sun has long been used to create electricity through solar

photovoltaic technologies. When sunlight (solar irradiation) comes into contact with layers of semi conducting material (usually silicone) electricity is generated through the creation of an electric field. The amount of electricity produced depends primarily (although not exclusively) on the intensity of the sunlight.

171. Solar irradiance levels (amount of energy received from the sun) for the

entire globe are well documented. The European Commission’s Photovoltaic Geographical Information System (PVGIS) is an example of an inventory that documents irradiation levels across Europe, Africa and South-West Asia. The PVGIS makes a geographical assessment of the solar resource and combines this with an assessment of the performance of photovoltaic technology to give the potential electricity generation yield from PV for each area (kWh/m2). Figure 8-1 shows part of the map of irradiance levels for an optimally inclined PV module in the UK45.

Figure 8-1: Map of UK global irradiance levels on an optimally inclined plane

45 Šúri M., Huld T.A., Dunlop E.D. Ossenbrink H.A., 2007. Potential of solar electricity generation in the European Union member states and candidate countries. Solar Energy, 81, 1295–1305, http://re.jrc.ec.europa.eu/pvgis/.

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172. As the above map indicates, Cornwall has the best solar resource in the UK. Whilst locally conditions may vary, the resource across Cornwall is almost constant. The yearly average irradiance on an optimally inclined plane only varies by 0.06 kWh/m2 between Bude and Land’s End. The table below summarises the average monthly irradiance levels per square metre on a horizontal, optimally inclined and vertical plane for Truro.

Month Horizontal (Wh/m2)

Optimum (Wh/m2)

Vertical (Wh/m2)

January 763 1220 1260 February 1460 2150 2030 March 2510 3200 2570 April 4190 4780 3170 May 5100 5190 2890 June 5240 5080 2610 July 5350 5320 2820 August 4340 4670 2880 Sept 3140 3880 2940 October 1740 2420 2150 November 1010 1650 1700 December 605 1000 1050 Average Yearly Irradiation Level

2960 3390 2340

Table 8-1: Summary of irradiance levels for Truro

8.2 Methodology 173. In addition to data on the geographical distribution of solar irradiance

intensity, the European Commission’s PVGIS also includes a PV estimation tool. The PV estimation tool estimates the output from solar PV arrays for any given location, based on a set of defined parameters. This enables a resource estimation to be made for a given area. Using the PV estimation tool this resource assessment has modelled three PV deployment scenarios to help understand the potential for solar PV in Cornwall. These scenarios are intended to represent the potential for deployment on rooftops and the potential for commercial scale free standing deployment.

174. In order to estimate the output that represents the average performance

of a solar PV array in Cornwall for each scenario, all scenarios were assumed to be located near to the centre of Cornwall (Truro being the location chosen). All scenarios assumed that crystalline silicon PV panels are used and are orientated to face south at an inclination of 35°, in order to provide the maximum yield (optimal orientation). Commercial solar PV

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arrays were assumed to be free-standing and roof-mounted panels were assumed to be building integrated.

175. The diagram below shows the process undertaken to assess the potential

solar PV resource in Cornwall.

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Solar PV Resource Assessment

Roof top deployment Ground mounted deployment

Identify the average rooftop array in Cornwall and

determine its performance

Identify the number of domestic and non-domestic

buildings which can reasonably support solar PV arrays

Calculate the total installed capacity

Discount sites which are technically constrained: Undevelopable land; Already developed land; Residential Amenity; Aspect; Proximity to the National Grid

Discount sites which are environmentally constrained: Areas of Outstanding Natural Beauty; National and Local Nature Reserves; Sites of Special Scientific Interest; Special Areas of Conservation; Special Protection Areas; RAMSAR Sites; The Heritage Coast; Cornwall Wildlife Sites; World Heritage Sites; Conservation Areas; Scheduled Ancient Monuments; Historic Parks and Gardens; Listed Buildings; Best and Most Versatile agricultural land;

Landscape Character and Cumulative Impact Identify the appropriate development sizes for the landscape and resize the unconstrained sites to fit

Aggregate the total output for each landscape character area and apply cumulative density factors

Convert the total installed capacity annual generation (GWh) and thousand tonnes of oil equivalent

Solar PV Resource Assessment

Roof top deployment Ground mounted deployment

Identify the average rooftop array in Cornwall and

determine its performance

Identify the number of domestic and non-domestic

buildings which can reasonably support solar PV arrays


Discount sites which are technically constrained: Undevelopable land; Already developed land; Residential Amenity; Aspect; Proximity to the National Grid

Discount sites which are environmentally constrained: Areas of Outstanding Natural Beauty; National and Local Nature Reserves; Sites of Special Scientific Interest; Special Areas of Conservation; Special Protection Areas; RAMSAR Sites; The Heritage Coast; Cornwall Wildlife Sites; World Heritage Sites; Conservation Areas; Scheduled Ancient Monuments; Historic Parks and Gardens; Listed Buildings; Best and Most Versatile agricultural land;

Landscape Character and Cumulative Impact Identify the appropriate development sizes for the landscape and resize the unconstrained sites to fit

Aggregate the total output for each landscape character area and apply cumulative density factors

Convert the total installed capacity annual generation (GWh) and thousand tonnes of oil equivalent

Figure 8-2: The Solar PV energy generation assessment process

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Rooftop deployment Domestic rooftops 176. The average domestic rooftop solar PV system installed in Cornwall (as

recorded under the Feed in Tariff (FIT) in its first year of operation) was approximately 2.5kW. This figure has therefore been used in this study to represent the rated peak output (installed capacity) of a typical domestic roof-mounted PV system in Cornwall.

177. For the purposes of this resource assessment the following assumptions

about the performance of panels were used within the model to calculate the output of a domestic PV array: Nominal power of the PV system: 2.5 kW (crystalline silicon) Estimated losses due to temperature: 12.5% (using local ambient

temperature) Estimated loss due to angular reflectance effects: 3.0% Other losses (cables, inverter etc.): 14.0% Combined PV system losses: 26.9%

178. Based on the above parameters, the table below summarises the

estimated electricity production for a typical 2.5kW domestic solar PV array.

Month

Average Daily Electricity Production

(kWh)

Average Monthly Electricity

Production (kWh)

January 2.40 74.4 February 4.17 117

March 6.02 187 April 8.67 260 May 9.28 288 June 8.97 269 July 9.33 289

August 8.21 255 September 6.98 209

October 4.47 138 November 3.17 95.2 December 1.95 60.5 Average 6.14 187

Total for Year 2,244

Table 8-2: Summary of estimated domestic electricity production

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179. On its own one domestic rooftop system may not make a significant contribution towards the electricity needs of Cornwall, but it can be much more significant when there is a large uptake of domestic microgeneration. A report outlining the method and findings of a microgeneration resource assessment for the South West of England was published by Regen South West in 201046. This report suggested that it is reasonable to assume that 25% of the domestic buildings in Cornwall can accommodate an average sized domestic PV installation. If 25% of Cornish homes had a 2.5kW PV installed it could make a significant contribution towards our electricity needs.

180. Council tax data recorded in April 2011 indicates that there are 253,868

households in Cornwall. If 25% were to have a 2.5kW solar PV rooftop installation the total installed capacity for domestic PV would be 158 MW with an average annual energy production of 142GWh. See below for the calculation:

1. Identifying the number of rooftops with PV: (Number of houses /

100 x 25 = Number of rooftops capable of accommodating an average rooftop PV array (2.5kW)). 253,868 / 100 x 25 = 63,467

2. Calculating the total installed capacity: (Number PV compatible

rooftops x 2.5 (kW) = total domestic rooftop capacity). 63,467 x 2.5 = 158,667.5kW

3. Calculating average annual electricity generation (GWh): (Number

of PV compatible rooftops x Total average production for the year). 63,467 x 2,244kWh = 142.419948 GWh/yr

Rooftop deployment - Non-domestic rooftops 181. Non-domestic buildings also have the potential to support solar PV arrays.

The Regen South West report47 on the microgeneration resource potential for Cornwall also considered the potential to deploy solar PV panels on commercial and industrial rooftops. It estimated that 40% of commercial and 80% of industrial rooftops are suitable for PV. The study calculates that the average PV array deployed on a commercial rooftop is approximately 5kW. The Regen South West report does not, however,

46 Regen South West (2010) Renewable and Low-carbon Energy Capacity Methodology. Methodology for the English Regions. (Online), Available: http://www.decc.gov.uk/assets/decc/what%20we%20do/uk%20energy%20supply/energy%20mix/renewable%20energy/ored/1_20100305105045_e_@@_methodologyfortheenglishregions.pdf 47 Regen South West (2010) Renewable and Low-carbon Energy Capacity Methodology. Methodology for the English Regions. (Online), Available: http://www.decc.gov.uk/assets/decc/what%20we%20do/uk%20energy%20supply/energy%20mix/renewable%20energy/ored/1_20100305105045_e_@@_methodologyfortheenglishregions.pdf

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specify a typical rooftop installation for industrial buildings. While it is recognised that industrial buildings can be very large they can also be small in Cornwall. Given this range of building sizes it was assumed that 5kW is also a suitable average array size for industrial buildings.

182. The following assumptions about the performance of commercial and

industrial rooftop panels were used within the PVGIS model to calculate the output of a 5kW roof-mounted system in Cornwall: Nominal power of the PV system: 5 kW (crystalline silicon) Estimated losses due to temperature: 12.4% (using local ambient

temperature) Estimated loss due to angular reflectance effects: 3.0% Other losses (cables, inverter etc.): 14.0% Combined PV system losses: 26.9%

183. Based on the above parameters, the table below summarises the

estimated electricity production from a 5kW roof mounted solar PV array.

Month


(kWh)


Production (kWh)

January 4.81 149 February 8.35 234



October 8.97 278 November 6.37 191 December 3.92 121 Average 12.30 375

Total for Year 4,490

Table 8-3: Summary of estimated domestic electricity production

184. Assuming that 40% of commercial rooftops and 80% of industrial rooftops

are suitable for solar PV Cornwall, has 16,951 rooftops available for PV. If 5kW arrays were installed on all these rooftops there would be a total installed capacity of 84.755 MW giving an annual average electricity production of 76 GWh. See below for calculation:

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1. Identifying the number of commercial buildings in Cornwall: (Total number of non-residential buildings / 100 x 25 = Number of commercial buildings) 27,342 / 100 x 25 = 6,835

2. Identifying the number of industrial buildings in Cornwall: (Total

number of non-residential buildings / 100 x 65 = Number of industrial buildings) 27,342 / 100 x 65 = 17,772

3. Identifying the number of commercial rooftops suitable for PV:

(Number of commercial rooftops / 100 x 40 = Number of commercial rooftops capable of accommodating an average rooftop PV array (5kW)). 6,835 / 100 x 40 = 2,734.

4. Identifying the number of industrial rooftops suitable for PV:

(Number of industrial rooftops / 100 x 80 = Number of industrial rooftops capable of accommodating an average rooftop PV array (5kW)). 17,772 / 100 x 80 = 14,217.

5. Calculating the total installed capacity (for both commercial and

industrial buildings): (Number PV compatible rooftops x 5 (kW) = total rooftop capacity). 16,951 x 5 = 84,755kW.

6. Calculating average annual electricity generation (GWh): (Number of

PV compatible rooftops x Total average production for the year (kWh)). 16,951 x 4,490 = 76.109990 GWh/yr.

Ground-Mounted Solar PV Deployment 185. Ground-mounted solar PV is different from roof-mounted in that it is

deployed on purpose built structures which sit on, or are anchored to, the ground. There is no ‘typical’ size of ground-mounted solar PV development, because the actual size is likely to be influenced by a number of case-specific factors, such as local environmental constraints, electricity grid access and capacity and economics. It is therefore difficult to determine a particular scale of development to model as part of a resource assessment. Consequently, the approach taken in this section was a constraints based assessment similar to that undertaken for onshore wind energy.

186. The table below shows the technical and environmental constraints that

were considered.

Technical Constraints Environmental Constraints

Undevelopable land Areas of Outstanding Natural

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Beauty Already developed land National and Local Nature Reserves Residential amenity Sites of Special Scientific Interest Aspect Special Areas of Conservation Proximity to the National Grid Special Protection Areas RAMSAR Sites The Heritage Coast Cornwall Wildlife Sites World Heritage Sites Conservation Areas Scheduled Ancient Monuments Historic Parks and Gardens Listed Buildings

Best and Most Versatile agricultural land

Landscape character Cumulative landscape impact

Table 8-4: Technical and environmental constraints to ground mounted solar PV development

Technical constraints 187. The following steps were undertaken to determine the available land that

is technically unconstrained:

188. Step 1: Land that was either undevelopable or already developed was discounted. This included land covered by buildings and settlements, roads, rivers (including the functional flood plain), trees and railways.

189. Step 2: A 10m buffer was applied to all buildings to allow for operational

and residential amenity considerations, such as car parks, private gardens and visual intrusion.

190. The map below shows the land that is considered generally unavailable to

ground mounted solar PV development, because it is already developed or being used for other (incompatible) purposes (steps 1 and 2).

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Figure 8-3: Land already in use for non-solar PV development

191. Step 3: Ground mounted solar PV is best orientated towards the south to

maximise direct exposure to the sun. All areas of land that are not either flat, or sloping on a southerly aspect (with an orientation ranging between south west and south east) were discounted to remove those areas where the topography did not provide sufficient direct sun exposure.

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Figure 8-4: Land in Cornwall with a southerly aspect

Environmental constraints 192. The following steps were undertaken to determine the available land that

is environmentally unconstrained:

193. Step 4: While it may be possible to integrate ground mounted solar PV into some sites which are designated for their environmental importance, it was considered that in most cases this would not be desirable. Therefore, land which benefits from the following designations was discounted: The Cornwall and Tamar Valley Areas of Outstanding Natural Beauty

(AONB); National and Local Nature Reserves; Sites of Special Scientific Interest; Special Areas of Conservation; Special Protection Areas; RAMSAR Sites; The Heritage Coast; Cornwall Wildlife Sites.

194. It is acknowledged that this is a cautious approach, particularly within the

AONB, given that the Cornwall AONB Management Plan encourages renewable energy technologies of appropriate types, scale and design.

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However, it is considered appropriate for a strategic assessment to adopt a cautious approach to Cornwall’s environmentally sensitive areas. The provision of roof top solar PV in these environmentally sensitive areas is not discounted and is dealt with in the roof top assessment section above.

Figure 8-5: Environmental designations in Cornwall

195. Step 5: Similarly, urban areas that are designated for their historic value

would not generally be conducive to ground mounted solar PV arrays unless they are small scale and carefully located. Therefore, urban areas designated as World Heritage Sites and Conservation Areas were discounted. The immediate setting of these designations can also be relevant to the designated statues of the area. It was therefore considered appropriate to apply a buffer zone of 500m around each designated urban area and discount that land from the assessment.

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Figure 8-6: Historic urban designations in Cornwall

196. Step 6: The same approach was taken for monuments or features that are

designated for their historic value, including the 500m buffer to take account of the need to consider the setting of the monument or feature. These features included: Scheduled Ancient Monuments; Historic Parks and Gardens; Listed buildings.

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Figure 8-7: Historic features and monuments in Cornwall

197. Step 7: There is potential for ground-mounted solar PV development to

conflict with the use of the land for agriculture. Deploying arrays of ground-mounted PV in a field would prevent many types of agriculture from taking place. It was therefore considered appropriate to discount the best and most versatile agricultural land from the assessment.

198. The agricultural land classification categorises agricultural land into

different grades designed to reflect their quality and versatility. ‘Best and Most Versatile’ land is recognised as being land that falls into grades 1 to 3a. In Cornwall not all grade 3 land has been classified into either a, or b. Consequently, the approach adopted for this assessment was to discount all grade 1, 2 and 3a land and to include all grade 3 (where the distinction between a and b has not been assessed), 3b, 4 and 5 land as having potential to be used for ground mounted solar PV.

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Figure 8-8: Best and Most Versatile agricultural land in Cornwall

Additional Considerations 199. Step 8: Access to the National Grid. Fiscal policy and the structure of the

UK energy market dictates that, in most cases, connection to the national electricity grid is a fundamental requirement of ground mounted solar PV development. There are instances when the electricity can be ‘private wired’ and would therefore not require grid connection, but electricity cannot be traded unless it can be exported to the grid. As a result, it was considered necessary to have regard to the proximity of unconstrained land for solar PV development to the grid.

200. Setting exact parameters for the proximity of a potential solar PV site to

the grid is complicated at the strategic level. It is possible, under regulatory provisions, to extend the grid infrastructure to accommodate new solar PV electricity generation. It should therefore be theoretically be possible to locate a ground-mounted solar PV development anywhere and extend the grid infrastructure to serve it. However, this scope for this is dependent on a number of factors, not least the amount that the developer is prepared to pay to have the grid infrastructure extended. It is also necessary to consider the capacity that the grid infrastructure has to accommodate more electricity generation and the feasibility of upgrading the infrastructure if additional capacity is needed.

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201. The factors governing the ability to connect into the grid vary depending on the location, size and structure of each development and the capacity of the available grid infrastructure. The resource assessment sought to broadly take account of this issue by assuming that land further then 2,000m from the existing 33kv network is not likely to be developed for ground mounted solar PV due to the cost of upgrading the grid infrastructure.

Figure 8-9: Distribution of National Grid infrastructure down to the 33kV line, with 2000m buffer.

202. Taking into account the need for reasonable proximity to exiting grid

infrastructure the remaining technically and environmentally unconstrained sites are shown in the map below.

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Figure 8-10: Technically and environmentally unconstrained land for ground mounted solar photovoltaic development

203. Step 9: Landscape Character and Cumulative Impact Landscape

constraints are, in effect, an environmental consideration for ground mounted solar PV development. They have, however, been dealt with separately in this assessment, because the constraint cannot be accounted for simply by discounting an area of land on a map.

204. The approach taken to assessing the degree to which landscape

considerations might constrain the deployment of solar PV has to respond to the variations in the character of the landscape and the degree to which the character of each area is likely to be impacted by ground mounted solar PV.

205. The landscape strategy, set out in the ‘Assessment of the Sensitivity of the

Landscape to On Shore Wind Energy and Large Scale Solar Photovoltaic Development in Cornwall’48, (the ‘landscape assessment’) provided the basis upon which to refine the results of the technical and environmental wind energy potential assessment to reflect the character of the landscape.

48 Assessment of the Sensitivity of the Landscape to On Shore Wind Energy and Large Scale Solar Photovoltaic Development in Cornwall. LUC, 2011.

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206. The landscape assessment set out a landscape strategy for each of Cornwall’s 40 Landscape Character Areas (LCAs)49 based on the sensitivity of each LCA.

207. The following four landscape strategy types were developed for Cornwall

as part of the Assessment: Solar PV landscapes; Landscapes with solar PV development; Landscapes with occasional solar PV development; Landscapes without solar PV development.

208. One of the four strategy types was applied to each of Cornwall’s LCAs to

reflect the level of sensitivity of the landscape in each area. The study found that there were no ‘solar PV development landscapes’ or ‘landscapes with solar PV development’ in Cornwall.

209. ‘Landscapes without solar PV development’ generally consist of moorland

and those landscapes designated as Areas of Outstanding Natural Beauty, or Heritage Coast. The resource assessment discounted potential sites within these landscapes (see the environmental constraints).

210. The detailed information contained within each strategy was used to

estimate the appropriate size and number of solar PV developments that might be realistic for each of the sites that were identified by applying in the technical and environmental constraints in the previous steps.

211. The following sections detail the steps taken to refine the resource

assessment to reflect the information within the landscape strategy. These steps have been listed below:

Step Action

9A Identify the appropriate size of development for each LCA

9B Refine the technically and environmentally unconstrained sites to reflect the appropriate size for each LCA

9C Refine totals to take account of potential cumulative impact Step 9A: Identify the appropriate size of development for each LCA 212. In order to refine the potential electricity generation capacity of the

technically and environmentally unconstrained sites to reflect the character of the landscape, it was first necessary to understand the appropriate size of solar PV development that can be accommodated in

49 Cornwall and Isles of Scilly Landscape Character Study. 2007. http://www.cornwall.gov.uk/default.aspx?page=24874

93

each LCA. This was done using the information set out in the landscape strategy for each LCA, which contains advice on the scale of individual PV developments that can be accommodated within the landscape (without fundamentally altering its characteristics).

213. The table below sets out the different scales of solar PV development used

in the landscape assessment and sets out the peak electricity output (the installed capacity) for each scale. Where the landscape strategy indicated that the appropriate solar PV development size is between two scales (e.g. ‘small to medium’), the mid point between the sizes was used (e.g. 7.5 hectares).

Solar PV development scale

Approximate average solar PV development size (interpreted from

landscape strategies) (hectares)

Estimated average installed capacity

(MW)

Very small 1 0.3 Very small – small 2.5 0.8 Small 5 1.7 Small – medium 7.5 2.5 Medium 10 3.3 Medium – large 12.5 4.2 Large 15 5

Table 8-5: Solar PV development sizes selected to reflect the varying landscape strategies across Cornwall

Note: The capacity per hectare was calculated based on 1 MW using approximately 3 hectares of land. Step 9B: Refine the technically and environmentally unconstrained sites to reflect the appropriate solar PV development size for each LCA 214. For each LCA the technically and environmentally unconstrained sites were

then refined into parcels of land commensurate with the appropriate PV development size for the landscape. Where areas of unconstrained land were more than double the largest appropriate development it was assumed that only 50% would be developable. This assumption was designed to reflect the fact that, while the landscape may not be able to accommodate a large single development, it might be able to accommodate more than one appropriately sized development where clear separation between those developments can be achieved. The total the amount of solar PV development that can be accommodated for each LCA

94

was then calculated using the potential installed capacity of these refined sites.

215. The table below shows the appropriate solar PV development size. The

table also sets out the potential installed capacity for each LCA from the technically and environmentally unconstrained sites, taking into account any necessary refinements to their size to reflect the appropriate development size for the landscape.

95

Landscape Character

Area Landscape Strategy Type

Approximate Scale of PV

System (hectares)

Estimated Installed

Capacity/System (MW)

Unconstrained area (hectares)

Potential Installed Capacity

(MW)

1 Landscape with occasional solar PV developments (very small scale)

1 0.3 1.2145 0.364

3 Landscape without solar PV developments except for very small very occasional

1 0.3 127.236 38.171

4 Landscape with occasional solar PV developments up to medium size

10 3.3 40.209 13.269

5 Landscape with occasional very small or small solar PV developments

2.5 0.8 2.1915 0.701

6 Landscape with occasional solar PV developments up to and including large scale

15 5 275.4495 91.817

9 Landscape without solar PV development except for very occasional very small scale

1 0.3 14.5065 4.352

10 Landscape with occasional small to medium size solar PV developments

7.5 2.5 325.8225 108.608


1 0.3 118.4775 35.543


1 0.3 0.614 0.184


1 0.3 136.1675 40.850


15 5 1053.268 351.089

15 Landscape with occasional solar PV developments very small or small scale

2.5 0.8 128.9095 41.251


15 5 150.181 50.060


15 5 642.4335 214.145

96

18 Landscape without solar PV developments except for very small very occasional developments

1 0.3 122.7465 36.824

19 Landscape with occasional solar PV developments up to and including medium scale

10 3.3 26.695 8.809

20 Landscape with occasional PV developments up to and including large scale

15 5 261.601 87.200


2.5 0.8 33.9335 10.859

22 Landscape with occasional PV developments up to and including large scale

15 5 1200.892 400.297

23 Landscape with occasional very small or small scale solar PV developments

2.5 0.8 155.284 49.691


2.5 0.8 47.302 15.13664


2.5 0.8 320.324 102.516


10 3.3 466.108 153.816


2.5 0.8 17.1825 5.498


2.5 0.8 40.7865 13.052

31 Landscape with occasional very small solar PV developments

1 0.3 356.2965 106.889

32 Landscape without solar PV except very occasional very small PV developments

1 0.3 200.2295 60.069

33 Landscape with occasional solar PV developments up to and including medium size

10 3.3 453.82 149.761


10 3.3 163.8495 54.070

35 Landscape without solar PV development except for very 1 0.3 1.5675 0.470

97

occasional very small scale


15 5 376.572 125.524


15 5 968.4745 322.825

38 Landscape with occasional solar PV developments up to and including medium size

10 3.3 186.091 61.410

39 Landscape with occasional very small or small solar PV developments (and possibly some ‘medium’ scale in the larger scale landscape areas)

5 1.7 168.367 57.225

40 Landscape with occasional very small, small or medium solar PV developments

5 1.7 214.1515 72.812

Table 8-6: Solar PV Development sizes and total output per LCA

98

Step 9C: Refine totals to take account of potential cumulative impact 216. In order to take account of the cumulative impact considerations

associated with multiple ground-mounted solar PV developments within the landscape, consideration needs to be given to the appropriate spread (or distribution), of developments.

217. Cumulative impact can only be truly assessed on a case by case basis, but

this assessment has attempted to take account of it at a strategic level by assigning a density factor to each landscape strategy type (as shown in the table below). A density factor has been chosen to reflect the appropriate level of separation for each landscape strategy (as advised by the landscape assessment).

218. The landscape assessment found that the landscape strategies ‘landscape

with occasional solar PV’ and ‘landscape without solar PV’ were the only applicable strategies for Cornwall. Within the ‘landscapes without solar PV’ the landscapes were generally considered incapable of supporting ground mounted solar PV, or able to accommodate very small developments spread very occasionally across the landscape. A density factor was therefore used to represent the ‘occasional’ and ‘very’ occasional patterns of distribution.

219. These density factors were applied to the aggregated total installed

capacity for all character areas within each landscape strategy. This was done at the aggregated level rather than the individual landscape level, because the distribution of technically and environmentally unconstrained sites is not uniform across Cornwall. The varied distribution means that applying a standard density factor at the individual LCA level would be misleading.

Landscape Strategy Density Factor (%)

Occasional solar PV development 25

Landscape without solar PV development (except very occasional)

10

Table 8-7: Density factors applied to represent the spread and grouping of solar PV developments for each landscape strategy type.

220. The matrix below shows the total potential installed capacity aggregated

for each of the different landscape strategies that arise in Cornwall, with the density factors applied.

99

Landscape Strategy

Occasional solar PV development

Without solar PV (except very occasional)

Landscape Total Installed Capacity (MW)

721.289 21.646

Total Land (hectares) 2019.352 72.155

Total Land (% of Cornwall) 0.57 0.02

Combined Total Land (% of Cornwall)

0.59

Combined Total Installed Capacity (MW)

742.935

Table 8-8: Total potential installed electricity generation capacity from ground-mounted solar PV in Cornwall.

221. The above figures show the peak output (installed) capacity for ground-

mounted solar PV in Cornwall. In order to understand the generating potential, the peak output capacity needs to be converted into the amount of electricity generated over time (in this case gigawatt hours per year).

222. For each solar PV system size (set out in table 8-5) the average annual

electricity generation can be calculated by multiplying the total number of PV developments (of each size) by the total yearly average production for that system size, based on its performance in Cornwall. The detailed assumptions and calculations are included in Appendix 3. The following calculation was used to estimate the annual output:

Installed capacity of the appropriate development size for each LCA (e.g. 0.3MW) / Total installed capacity for the unconstrained sites within all LCA to which this development size is applicable X Annual output for the particular system size (derived from the PVGIS calculations).

223. The table below shows to total annual output for each PV system size,

based on the landscape strategies for relevant for Cornwall.

Size of Solar PV System

(hectares)

Total Annual Output (GWh/yr)

Landscapes without PV except very occasional

Landscapes with occasional PV

1 205.640 101.89

100

2.5 0 226.770 5 0 123.153

7.5 0 102.960 10 0 418.410

12.5 0 0 15 0 1560.809

Total 205.640 2533.992

Combined Total 2739.632

Table 8-9: Total annual output per size of Solar PV system

224. As with the installed capacity calculations set out in the table above (8-8),

the annual output from each system size needs to be combined (based on the relevant landscape character) and a density factor applied ensure an appropriate spread of systems can be achieved within the landscape.

225. The table below shows the combined annual output from ground-mounted

solar PV development in Cornwall, using the density factors set out in table 8-7.

Landscape Strategy

Very occasional solar PV

development

Occasional solar PV development

Landscape Total Annual Electricity Output (GWhr/yr)

20.564 633.498

Combined Total Annual Electricity Output (GWhr/yr)

654.062

Table 8-10: Potential average annual electricity output from ground-mounted solar PV development in Cornwall

8.3 Results 226. The table below summarises the average yearly solar PV generating

capacity potential in Cornwall for each scale of PV deployment.

PV Development Potential Annual Average Electricity

Generation (GWh/yr)

Rooftop Installations (average 2.5kW)

243.668

101

Ground Mounted Installations 742.935

All PV Installations Combined 986.358

Table 8-11: Summary of average yearly electricity generation capacity potential from solar PV in Cornwall for each scale of PV deployment.

227. The table below summarises the total average yearly solar PV generating

capacity potential in Cornwall.


Average capacity factor of technology 0.1


Potential energy production in thousands of tonnes of oil equivalent per year.

75.029

Table 8-12: Summary of total average yearly electricity generation capacity potential from solar PV in Cornwall

8.4 List of Layers

GIS Layer Category Source Undevelopable land Resource BERR/DECC Aspect Resource Cornwall Council Residential amenity Residential Cornwall Council

Proximity to the National Grid Electricity Distribution Western Power Distribution

Areas of Outstanding Natural Beauty National and Local Nature Reserves Sites of Special Scientific Interest Special Areas of Conservation Special Protection Areas RAMSAR Sites Cornwall Wildlife Sites

Environmental Cornwall Council

The Heritage Coast World Heritage Sites Conservation Areas

Heritage Cornwall Council

102

Scheduled Ancient Monuments Historic Parks and Gardens Listed Buildings Best and Most Versatile agricultural land

Agriculture Cornwall Council

Table 8-13: Summary of the GIS layers used in the wind assessment.

103

9 Solar Thermal

9.1 Background 228. The following section sets out the estimated potential capacity for solar

thermal in Cornwall. Unlike the assessment of the solar PV potential (chapter 8), which assessed the potential for roof and ground mounted systems, this assessment focussed on the domestic scale roof mounted installations.

229. There are a number of reasons for this focus. Large scale ground mounted

solar thermal systems have not yet been deployed in Cornwall and there is little evidence of an appetite to install solar thermal at scale at present. For heating systems to by useful and for subsidy to be claimed they require a user of the heat. Due to the costly infrastructure needed to transport heat over distance the heat users need to be located in close proximity to the generator. While large solar thermal systems do theoretically have a role to play as part of heat networks, their location would be heat demand-lead and their deployment will depend on how the technology fares in an assessment of the economic and technical performance of a range of heat sources. The range of alternative technical options means that solar thermal is unlikely to have more than a niche role to play in large scale heating and communal heating systems.

230. These factors make the take up or large scale solar thermal systems in

Cornwall difficult to predict and a meaningful understanding of the potential to deploy such systems at scale difficult to assess. For the purposes of this assessment, it is therefore considered that individual building-integrated systems constitute the solar thermal heating resource potential for Cornwall.

9.2 Methodology 231. It is recognised that building-integrated solar thermal systems vary

depending on the heat demand of each building, but a typical standardised installation is required to model the potential overall yield for Cornwall.

232. The diagram below shows the process undertaken to assess the solar

thermal energy generation potential in Cornwall.

104

Solar Thermal Resource Assessment

Identify the average size of rooftop solar thermal systems in Cornwall and determine its performance

Identify the number of domestic and non-domestic buildings which can reasonably support solar thermal systems



Solar Thermal Resource Assessment

Identify the average size of rooftop solar thermal systems in Cornwall and determine its performance

Identify the number of domestic and non-domestic buildings which can reasonably support solar thermal systems



Figure 9-1: The solar thermal resource assessment process

233. The Regen South West ‘Renewable Energy Progress Report: South West

2012 Annual Survey’50 records that in April 2012 there were 531 solar thermal systems installed in Cornwall and the Isles of Scilly with a total capacity of 1.670MW. Using these figures the average solar thermal system in Cornwall can be calculated (3.15kW). For the purposes of this assessment the typical solar thermal system in Cornwall is assumed to be 3.15kW. The following assumptions were made about the type and performance of the system modelled in this assessment.

234. Assumed typical installation:

Average installed capacity - 3.15kWth System type - Direct Active Evacuated Tube Mounting and aspect - Roof mounted at 35% Orientated - directly south. Zero loss efficiency (i.e. panel fluid temperature is the same as

ambient). 235. The output of a solar thermal system can be estimated using the following

calculation:

50 Regen South West http://regensw.s3.amazonaws.com/final_web_version_156da5ede9b529d2.pdf

105

Positioning factor (tilt and orientation) x Solar Irradiation (approx 1200 kWh/m²/year for Cornwall) X Area of the Solar Array (m2) x the Collector Performance Factor (0.46 based on the AES EN12975 Test Report).51

236. The physical size of a 3.15kW solar thermal system (the footprint) can be

calculated by dividing the installed capacity by the conversion factor of 0.752. Based on these figures the typical installation will produce: 1 x 1200 x 4.5m² x 0.46 = 2,484 kWh/yr.

237. In order to translate the estimated output of the typical solar thermal

system in Cornwall into the overall potential the number of rooftops that might be suitable to accommodate an installation. Solar thermal can be used for a range of applications, but water heating is its primary use in buildings. Of the different building types, domestic buildings are most likely to make use of a solar thermal system to heat water for washing and bathing, or to integrate into a heating system. In general these uses do not lend themselves to commercial and industrial buildings, particularly as a retrofit option for existing buildings. For the purposes of this assessment domestic roofs were considered suitable for solar thermal installations. The report commissioned by the Department of Energy and Climate Change in 2010 entitled ‘Renewable and Low-carbon Energy Capacity Methodology - Methodology for the English Regions’53 estimated that 25% of homes in Cornwall were capable of accommodating solar thermal. For the purposes of this assessment the figure was reduced to 15% to take account of the fact that many combination boilers are not modulating (can’t accept pre-heated water), so are less likely to encourage integrated solar thermal systems. The steps for calculating the potential solar thermal heat generation potential in Cornwall are set out below:

1. Number of houses / 100 x 15 = Number of rooftops capable of

accommodating an average solar thermal installation. 253,868 / 100 x 15 = 38,080.2

2. Calculating the total installed capacity: (Number PV compatible

rooftops x 3.15 (kW) = total domestic rooftop capacity). 38,080.2 x 3.15 = 119,952.63 kW

3. Calculating average annual generation (GWh): (Number of PV

compatible rooftops x Total average production for the year). 38,080.2 x 2,484kWh = 94.591 GWh/yr

51 http://www.aessolar.co.uk/downloads/AES%20-%20Estimating%20Solar%20Thermal%20Performance.pdf 52 http://www.iea-shc.org/welcome/Technical_note_solar_thermal_capacity.doc 53 http://www.decc.gov.uk/assets/decc/what%20we%20do/uk%20energy%20supply/energy%20mix/renewable%20energy/ored/1_20100305105045_e_@@_methodologyfortheenglishregions.pdf

106

9.3 Results 238. The table below summarises the total average yearly solar thermal (heat

energy) generation capacity potential on domestic rooftops in Cornwall.

Potential constrained installed capacity (MWth) 119.953


Potential energy produced in thousand tonnes of oil equivalent per year.

8.13

Table 9-1: Summary of Total Average Yearly Thermal Generation Capacity Potential from Domestic Solar Thermal in Cornwall.

107

10 Geothermal 239. Cornwall has historically been a place where considerable research has

been undertaken on geothermal energy, in particular through the Hot Dry Rocks54 project at Rosemanowes Quarry near Camborne. Cornwall’s geology contains substantial areas of granite which are located close to the surface. It is this relatively accessible granite that provides the opportunity to extract high grade heat that can be used to produce electricity. The heat that remains following the electricity production process can also be used for low grade heat uses such as space heating or market gardening.

240. At the time of preparing this report, planning permission had been granted

for two geothermal projects near St Austell and St Day. The first is a project being undertaken by a partnership between the Eden Project and EGS Energy Limited. The aim of the project is to provide both electricity and heat for the Eden Project site. The power plant will consist of two 3-4km bore holes. Water will be circulated down the injection well where it will be heated by the hot rocks at the bottom. The water will return up the production well, reaching approximately 150°C at the surface. The power plant will have an electrical capacity of 3MW. Planning consent was granted in October 201055.

241. The second project is being undertaken by Geothermal Engineering Ltd.

The project is located next to the United Downs waste site. The project will aim to start with a 4.5km test bore hole to determine the suitability of the site. The power plant is intended to produce 10MW of base load electricity and up to 55MW of renewable heat for local use. The project aims to be operational by 2013. Planning consent was granted in December 201056.

242. It can be seen, even from these projects (which have permission, but have

not yet begun construction), that there remain some uncertainties in the viability of developing deep geothermal energy generation plants in Cornwall. It is therefore difficult to accurately assess the potential of generating heat and electricity from this energy source in Cornwall.

243. While it does not estimate the potential for geothermal in Cornwall, Figure

0-1 shows where the geothermal hot spots are located. The map is a reproduction of the Cornwall area from a map of the UK from the British

54 Hot Rocks Project http://www.energysavingwarehouse.co.uk/news/185/20/Geothermal-Energy.html 55 Planning reference no. NR/10/00056/GEO http://planning.cornwall.gov.uk/online-applications/ 56 Planning reference no. PA10/04671 http://planning.cornwall.gov.uk/online-applications/

108

Geological Survey report ‘Initial geological considerations before installing ground source heat pump systems’57.

244. It is recognised that there is Government support for and commitment to

deep geothermal engineers systems. It is also recognised that geothermal, once operational plants are successfully installed, stands to make a significant contribution to the energy mix in Cornwall. A report prepared by Sinclair Knight Merz in May 2012 for the Renewable Energy Association suggested that there is sufficient resource in Cornwall and the South West to support 4,000 MWe and 13,000 MWth through Engineered Geothermal Systems. This, however, is based on an assessment of the inferred resource, which includes a number of reasonably high level assumptions about the geology in Cornwall and does not take account of land use constraints.

245. However, until the technology is proven through successful installation and

operation, it will not be possible to produce a meaningful estimation of the renewable energy potential that can be met from deep geothermal sources in Cornwall. Consequently, while acknowledging that deep geothermal has the potential to be a significant resource this resource assessment has not attempted to quantify the resource.


Figure 10-1: Map of Heat flow at the Surface

57 British Geological Survey report ‘Initial geological considerations before installing ground source heat pump systems’ http://www.bgs.ac.uk/research/energy/docs/final_paper.pdf

109

11 Future improvements 246. This study provides an assessment of the potential to generate renewable

and low carbon energy from resources in Cornwall, taking into account a range of constraining factors, including planning considerations. As such, it attempts to provide a realistic estimation of the energy generation that can be realised.

247. There are, however, some areas where changing technological or

economic circumstances may necessitate further work. The solar thermal assessment concentrated on the potential for installing systems on domestic rooftops. This chapter may be further developed by an assessment of the potential to install large scale solar thermal systems; particularly if/when large scale ground-mounted solar thermal heating systems find a viable application in Cornwall.

248. The hydropower study that was carried out on behalf of the Environment

Agency was a National desk based study. A specific study looking in further detail at potential locations and constraints to hydropower, based on a site appraisal of the resources identified in the Environment Agency study, would provide a more detailed understanding of the opportunities to exploit the resource.

249. No estimated figure has been provided for deep Geothermal, because it is

considered that, until the technology is proven and the resource potential is quantified, it will not be possible to produce a meaningful estimation of the renewable electricity and heat generation potential in Cornwall. However, as the two projects that have been granted planning permission progress there may be potential for future work to be carried out that will allow a meaningful resource assessment to be carried out.

250. The potential to supply heat from heat pumps was not considered by this

assessment. Heat pumps are not recognised as renewable energy technologies because they require electricity to operate. However, they may be considered low carbon due to their efficient use of electricity. In order to understand to potential to decarbonise Cornwall’s space heating requirements it may be useful to carry out a future assessment of Air, Ground, and Water Sourced Heat Pump potential in Cornwall.

251. A further complimentary study may be merited to consider the ‘delivery’ of

the renewable energy potential. Such a study may be useful to help understand the timeframe and investment required to install the generation installations and to the necessary supply and servicing infrastructure required to realise the potential in Cornwall.

110

12 Conclusions 252. This assessment indicates that we can generate approximately 3,076

GWhr each year from a potential installed capacity of 1,617 MW from renewable and low carbon energy sources. This is a significant figure and offers the opportunity to dramatically reduce the carbon emissions associated with energy consumption in Cornwall.

253. If existing technologies develop further as a result of new opportunities

and applications (e.g. deep geothermal and large scale solar thermal) this figure may increase significantly. Similarly, the development and deployment of new technologies could increase the potential resource.

254. It is clear that Cornwall has a great resource from which clean energy can

be generated. This resource also offers a significant economic opportunity for Cornwall in terms of developing a low carbon economy and securing a greater proportion of the supply and profit associated with its energy supply.

111

List of Acronyms AD Anaerobic digestion agl Above ground Level ALC Agricultural Land Classification BERR Department for Business, Enterprise & Regulatory Reform BIS Department for Business, Innovation and Skills CAA Civil Aviation Authority C&I Commercial and Industrial DEFRA Department for Environment, Food and Rural Affairs dte Dry tonnes equivalent EfW Energy from Waste FRA Flood Risk Assessment GIS Geographical Information System LOS Line of Sight MSW Municipal Solid Waste NATS National Air Traffic Services OFCOM Office of Communication PPG Planning Policy Guidance PPS Planning Policy Statement PV Photovoltaic SRC Short Rotational Coppice WPD Western Power Distribution kW Kilowatt – unit of power MW Megawatt – unit of power kWh Kilowatt hour – unit of energy MWh Megawatt hour – unit of energy GWh Gigawatt hour – unit of energy Ktoe thousand tonnes of oil equivalent

112

Appendix

113

Appendix 1: Output per LCA when cumulative impact considerations (density factors) applied.

Landscape Character

Area Landscape Strategy Type

Estimated Output

/km2 (MW)

Unconstrained area (km2)

Potential Installed

Capacity (MW) (with Technical

and Environmental constraints)

Retained MW (after

applying density factors)


14 0.64 8.96 1.792


14 0.02 0.28 0.056


14 2.9 40.6 4.06

7 Landscape without wind turbines except on the plateau to the north where large turbines might be accommodated

11 6.22 68.42 13.684

9 Landscape with occasional single, or small clusters of turbines up to the medium scale

14 0.69 9.66 1.932

10 Landscape with occasional single, or small clusters of turbines up to the smaller end of the large scale

14 2.23 31.22 3.122


14 0.42 5.88 1.176

13 Landscape with occasional single turbines to medium sized clusters of turbines up to an including the medium scale

14 6.91 96.74 9.674

14 Landscape with wind energy development with small or medium clusters of turbines up to the smaller end of the large scale

11 11.69 128.59 61.723

15 Landscape with occasional single turbines or small clusters of turbines up to and including the medium scale

14 2.89 40.46 8.092

114

16 Landscape with occasional small clusters of turbines, or single turbines up to the lower end of the large scale

11 3.67 40.37 4.034

17 Landscape with occasional small, medium or large clusters of turbines up to the large scale

11 4.55 50.05 20.2


11 8.57 94.27 45.25

19 Landscape with occasional single turbines or small clusters up to and including the medium scale

14 3.01 42.14 4.214


14 2.77 31.78 6.36


14 1.32 18.48 3.696

22 Landscape with occasional small or medium clusters of turbines up to the lower end of the large scale

11 15.2 167.2 33.44

24 Landscape with occasional single turbines of the very small scale

0.15 0.91 0.137 0.014


14 1.63 22.82 2.282

26 Landscape with occasional small clusters of turbines up to the lower end of the large scale

11 6.49 90.86 18.172

28 Landscape with occasional single of small clusters of turbines up to and including the medium scale

14 1.24 17.36 3.472

29 Landscape with occasional single turbines of the very small, or small scale

0.15 0.14 0.021 0.002

31 Landscape with occasional small or medium clusters of turbines up to and including the medium scale

14 6.3 88.2 26.46

33 Landscape with occasional small or medium scale clusters of turbines up to the smaller end of the large scale

11 6.75 74.25 22.275

34 Landscape with occasional single or small clusters of turbines up to the and including the medium scale

14 2.89 40.46 4.046

36 Landscape with wind turbines comprising small or medium clusters of turbines up to the smaller end of the

11 12.19 134.09 42.9

115

large scale

37 Landscape with occasional single of small clusters of turbines up to the smaller end of the large scale

11 21.73 239.03 23.903

38 Landscape with occasional single or small clusters of turbines up to the medium scale

14 7.82 109.48 21.896

39 Landscape with occasional single or small to medium scale turbines up to the smaller end of the large scale

11 3.27 35.97 3.597

40 Landscape with occasional single or small clusters of turbines up to the large scale

11 9.98 109.78 10.978

Total 402.502

- 116 -

Appendix 2: Capacity Factor of Wind Farms in Cornwall Taken from the UK Renewables Obligation (RO) data (http://www.ref.org.uk/roc-generators/search.php) Goonhilly

RO Period Capacity

(kW) Capacity Factor

MWh ROCs

2010/2011 12,090 14,274 14,274 2011/2012 12,090 31,397 31,397

Rolling Load Factor 30.4 % Roskrow Barton:

RO Period Capacity


MWh ROCs

2007/2008 1,700 1,597 1,597 2008/2009 1,700 34.2% 5,096 5,096 2009/2010 1,700 31.9% 4,754 4,754 2010/2011 1,700 27.3% 4,059 4,059 2011/2012 1,700 4,870 4,870

Rolling Load Factor 31.5 % Four Burrows:

RO Period Capacity (kW) Capacity Factor

MWh ROCs

2002/2003 4,500 23.6% 9,297 9,297

2003/2004 4,500 21.0% 8,286 8,286

2004/2005 4,500 22.4% 8,848 8,848

2005/2006 4,500 20.5% 8,089 8,089

2006/2007 4,500 23.2% 9,148 9,148

2007/2008 4,500 22.0% 8,692 8,692

2008/2009 4,500 20.2% 7,951 7,951

2009/2010 4,500 19.5% 7,701 7,701

2010/2011 4,500 15.4% 6,077 6,077

2011/2012 4,500 8,456 8,456

Rolling Load Factor 20.9 % Carland Cross:


MWh ROCs

2002/2003 6,000 27.4% 14,390 14,390

2003/2004 6,000 25.5% 13,453 13,453

2004/2005 6,000 26.5% 13,925 13,925

2005/2006 6,000 25.6% 13,460 13,460

2006/2007 6,000 28.7% 15,090 15,090

2007/2008 6,000 22.6% 11,916 11,916

2008/2009 6,000 24.7% 12,991 12,991

- 117 -

2009/2010 6,000 22.7% 11,907 11,907

2010/2011 6,000 18.4% 9,666 9,666

2011/2012 6,000 26.0% 13,689 13,689

Rolling Load Factor 24.7 % Bears Down:

RO Period Capacity


MWh ROCs

2002/2003 9,600 28.5% 23,948 23,948 2003/2004 9,600 26.9% 22,690 22,690 2004/2005 9,600 27.4% 23,002 23,002 2005/2006 9,600 25.4% 21,354 21,354 2006/2007 9,600 28.3% 23,825 23,825 2007/2008 9,600 26.0% 21,921 21,921 2008/2009 9,600 24.8% 20,892 20,892 2009/2010 9,600 23.9% 20,103 20,103 2010/2011 9,600 20.1% 16,865 16,865 2011/2012 9,600 26.4% 22,264 22,264

Rolling Load Factor 25.7 % St Breock:


MWh ROCs

2002/2003 5,000 28.0% 12,246 12,246

2003/2004 5,000 26.0% 11,428 11,428

2004/2005 5,000 27.1% 11,852 11,852

2005/2006 5,000 24.3% 10,633 10,633

2006/2007 5,000 26.4% 11,553 11,553

2007/2008 5,000 10,328 10,328

2008/2009 5,000 24.3% 10,623 10,623

2009/2010 5,000 21.8% 9,531 9,531

2010/2011 5,000 17.9% 7,861 7,861

2011/2012 5,000 10,595 10,595

Rolling Load Factor 24.3 % Delabole:


MWh ROCs

2010/2011 9,200 7,648 7,648

2011/2012 9,200 31.4% 25,350 25,350

Rolling Load Factor 30.5 % Cold Northcott:


MWh ROCs

2002/2003 6,800 24.4% 14,521 14,521

- 118 -

2003/2004 6,800 23.3% 13,947 13,947

2004/2005 6,800 24.2% 14,390 14,390

2005/2006 6,800 22.4% 13,344 13,344

2006/2007 6,800 25.4% 15,158 15,158

2007/2008 6,800 23.2% 13,868 13,868

2008/2009 6,800 22.8% 13,572 13,572

2009/2010 6,800 20.1% 11,949 11,949

2010/2011 6,800 15.8% 9,399 9,399

2011/2012 6,800 22.2% 13,241 13,241

Rolling Capacity Factor 22.3 % Overall Average Capacity Factor: 26.28%

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Appendix 3: Calculated outputs for solar PV systems in Cornwall.

Installed Capacity (MW) Size of Solar PV System (hectares)

Landscapes without PV, except very occasional

landscapes with occasional PV

1 216.436 107.253 2.5 0 238.705 5 0 130.037

7.5 0 108.608 10 0 441.135

12.5 0 0 15 0 1642.957

Total 216.436 2668.695 Total installed capacity for each size of solar PV system

The following assumptions about the performance ground mounted solar PV systems were included within the PVGIS model to calculate their output in Cornwall:

Estimated losses due to temperature: 7.9% (using local ambient temperature)

Estimated loss due to angular reflectance effects: 3.0% Other losses (cables, inverter etc.): 14.0% Combined PV system losses: 23.1%

Based on the above parameters the following tables below summarise the estimated electricity production for the typical scale of solar PV development for each landscape type.

Month


(kWh)


Production (kWh)




October 567.00 17600

- 120 -

November 401.00 12000 December 247.00 7650 Average 780 23700

Total Yearly Average Production

285000

Summary of Estimated Commercial Electricity Production from the 0.3MW systems

Month


(kWh)


Production (kWh)




October 1510.00 46900 November 1070.00 32100 December 658.00 20400 Average 2080 63300


760000


Month


(kWh)


Production (kWh)



August 5930.00 184000

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September 5020.00 151000 October 3210.00 99600



1610000


Month


(kWh)


Production (kWh)






2370000


Month


(kWh)


Production (kWh)


March 8390.00 260000 April 12200.00 365000 May 13000.00 403000 June 12600.00 377000

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July 13100.00 405000 August 11500.00 357000

September 9750.00 293000 October 6240.00 193000



3130000


Month


(kWh)


Production (kWh)






3990000


Month


(kWh)


Production (kWh)


March 12700.00 394000 April 18400.00 553000

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May 19700.00 611000 June 19000.00 571000 July 19800.00 614000




4750000

Summary of Estimated Commercial Electricity Production from the 5MW systems