appendix 17b - wrate assessment - planning inspectorate · sncr selective non catalytic reduction...

Ferrybridge Multifuel 2 (FM2)

Document Ref: 6.4.24

Environmental Statement – Volume III (Appendices)

July 2014 Appendix 17B

APPENDIX 17B: WRATE ASSESSMENT REPORT



PINS Ref: EN010061


Ferrybridge Power Station Site, Knottingley, West Yorkshire

Appendix 17B WRATE Assessment Report

The Planning Act 2008

The Infrastructure Planning (Applications: Prescribed Forms and Procedure)

Regulations 2009 (as amended) Regulation 5(2)(a)

The Infrastructure Planning (Environmental Impact Assessment) Regulations

2009

Applicant: Multifuel Energy Limited

Date: July 2014


Document Ref:6.4.24


July 2014 (i)

Document Number 6.4.24

Revision

Author

Signed R Hamblin Date 21/7/14

Approved By

Signed M Bains Date 21/7/14

Document Owner URS

Revision History

Revision No. Date Reason for Revision Authorised By

Submission version 30/7/14 K Cobb




July 2014 (ii)

Glossary

CCGT Combined Cycle Gas Turbine

CHP Combined Heat and Power

C&I Commercial and Industrial

ES Environmental Statement

FGT Flue Gas Treatment

GWP Global Warming Potential

HDPE High-density Polyethylene

HTP Human Toxicity Potentials

IBA Incinerator Bottom Ash

LCA Life Cycle Analysis

MBT Mechanical and Biological Treatment

MRF Materials Recycling Facility

MSW Municipal Solid Waste NCV Net Calorific Value

SNCR Selective Non Catalytic Reduction

tpa tonnes per annum

WEEE Waste Electric and Electronic Equipment

WDF Waste Derived Fuel

WRATE Waste and Resources Assessment Tool for the Environment




July 2014 (iii)

CONTENTS

17B. WRATE ASSESSMENT REPORT ............................................................................. 1

17B.1. Introduction to WRATE ................................................................................................ 1

17B.2. Impact Assessment ..................................................................................................... 2

17B.3. Assessment ................................................................................................................. 3

Assessment Summary ................................................................................................. 3

Waste Composition ..................................................................................................... 4

Waste Pre-treatment ................................................................................................... 6

Transport ..................................................................................................................... 7

Recycling ..................................................................................................................... 7

Energy Recovery – Proposed Development ............................................................... 8

Landfill ......................................................................................................................... 8

17B.4. Results ....................................................................................................................... 10

17B.5. Model Analysis........................................................................................................... 14

Variation to annual throughput - 425,000 tonnes ...................................................... 14

Variation to annual throughput - 675,000 tonnes ...................................................... 15

Pre-treatment ............................................................................................................. 20

Transport Distances .................................................................................................. 20

Proposed Development Outputs ............................................................................... 21

17B.6. Conclusions ............................................................................................................... 22

17B.7. References ................................................................................................................ 23




July 2014 Page 1 of Appendix 17B

17B. WRATE ASSESSMENT REPORT

17B.1. Introduction to WRATE

17B.1.1. An assessment of the Proposed Development (Ferrybridge Multifuel 2) has been

undertaken using the Environment Agency’s WRATE (Waste and Resources Assessment

Tool for the Environment) lifecycle assessment tool to evaluate the relative environmental

burden of the chosen waste management routes.

17B.1.2. WRATE is a Life Cycle Assessment (LCA) model that was first developed by the

Environment Agency in 2007. WRATE allows users to quantify and compare the relative

environmental burdens of equivalent integrated waste management systems across their

entire life cycle.

17B.1.3. WRATE calculates the potential impacts arising from all processes in the waste

management system including the collection, transportation, transfer, treatment, disposal

and recycling of materials. The model takes account of the construction and operation of

infrastructure and vehicles, and offsets this burden against the avoided burdens

associated with materials and energy recovery. All inputs of waste, energy and materials,

and outputs of energy, process residues, materials and emissions are accounted for.

17B.1.4. Background data are provided by built-in databases, namely:

• the energy-mix database, which contains information related to the electricity

generation mix, energy generation efficiency, losses during electricity transport and

marginal electricity production; and

• the waste composition database, which contains the information relating to the type

and quantity of waste, including a pre-defined elemental waste composition for each

waste fraction, a default waste composition and calorific value and moisture content.

17B.1.5. In using WRATE the user specifies the waste stream(s) to be managed, then defines the

way in which the waste is to be managed, step by step, including (as appropriate) the

collection medium, vehicles, intermediate facilities, treatment, recovery and/or final

disposal. WRATE calculates and presents the environmental impacts in terms of six

default impacts: abiotic resource depletion, freshwater, aquatic ecotoxicology,

acidification, eutrophication, global warming potential and human toxicity.

17B.1.6. For the purpose of this assessment, the impact in terms of global warming potential

(GWP) only is considered in detail, as these data are to be utilised in the carbon

assessment for the Proposed Development. Outputs from the WRATE analysis have

informed Chapter 4 Need, Alternatives and Design Evolution and Chapter 17

Sustainability of the Environmental Statement (ES). The analysis has also taken

account of, and been developed in conjunction with, the Fuel Availability and Waste

Hierarchy Assessment (Application Document Ref. No. 5.9) for the Proposed

Development.

17B.1.7. In completing the WRATE assessment, the software version 2.0.1.8, (built 26/10/2012)

was used, which draws on guidance provided in:

• ISO 14040:1997 – Principles and framework;

• ISO 14041:1998 – Goal and scope definition and inventory analysis;

• ISO 14042:2000 – Life cycle impact assessment;

• ISO 14043:2000 – Life cycle interpretation;

• ISO 14048:2002 – Data documentation format; and

• ISO 14049:2000 – Examples of application of ISO 14041 to goal and scope definition

and inventory analysis.





17B.2. Impact Assessment

17B.2.1. The primary purpose of this assessment is to assess the carbon impact of the Proposed

Development. Climate change (i.e. Global Warming Potential) (GWP100a) is an

assessment of the amount of carbon dioxide and other gases emitted that cause global

warming. Apart from CO2, the other major greenhouse gas is methane (CH4). Methane is

considered 23 times more potent than CO2 in terms of its effect on global warming over a

100 year period. Climate change impact in WRATE is expressed in kg CO2-equivalent

(eq).

17B.2.2. It is important to note that where the model results show a minus value for the kg CO2-eq

this is not indicative of a process being a carbon ‘sink’ but of a process displacing

conventional energy or electricity use, and hence resulting lower global emissions than

would be the case under the default scenario. The energy mix selected for this

assessment is the default WRATE 2020 energy mix. The electricity displaced by the

Proposed Development would be made up of a mix of generation types known as the

‘marginal’ mix. This mix is forecast by WRATE (using Department of Energy and Climate

Change [DECC] data) for every year up until 2020. For this assessment, the year of study

was selected as 2020. WRATE forecasts the marginal energy mix for that year to be

33.8% coal, 4.2% gas and 62.0% gas – Combined Cycle Gas Turbine (CCGT).

17B.2.3. It is recognised that the Defra publication ‘Energy from Waste – A guide to the debate

Feb 2014’ (ref 17B-1) states that “A gas fired power station (Combined Cycle Gas

Turbine – CCGT) is the current standard comparator as this is the marginal technology if

you wanted to build a new power station today.” If 100% CCGT were used as the

comparator this would reduce the overall benefit predicted for the Proposed

Development, although a benefit would still be predicted. The predicted effect of the

change in energy mix is heavily dependent on the carbon intensity and emission factors

used in the assessment. Estimates of carbon intensities for different types of energy

generation are provided in the carbon assessment (Appendix 17A).

17B.2.4. The other Environment Agency default impacts that are reported by WRATE (but which

are not relevant to this carbon footprint assessment) include the following:

• Acidification Potential; average European (kg SO2-Eq) – this relates to the release of

acidic gases such as sulphur dioxide that have the potential to react with water in the

atmosphere to form ‘acid rain’ and causing damage to the environment.

• Eutrophication Potential (kg PO4-EQ) – this relates to the release of nitrate and

phosphate. Increased concentrations in water and soils can result in increased algal

growth reducing the oxygen in the water and damage to plant stability in soils, both

damaging the environment.

• Freshwater Aquatic Ecotoxicity: FAETP infinite (kg1,4-DCB-Eq) – this relates to the

impact of toxic substances on aquatic organisms and the bioaccumulation of toxins

such as mobile heavy metals.

• Human Toxicity: HTP infinite (kg 1,4-DCB-Eq) – this relates to the impacts on human

health. Characterisation factors, expressed as Human Toxicity Potentials (HTP)

describe fate, exposure and the effects of toxic substances.

• Resources: depletion of abiotic resources (kg antimony-Eq) – this relates to the

extraction of raw materials and resources. An abiotic depletion factor is determined for

each mineral or fossil fuel based on the rate of extraction and the global resource

reserves.





17B.3. Assessment

Assessment Summary

17B.3.1. Scenario 1 is the disposal of pre-treated waste to landfill (landfill baseline) and scenario 2

is the combustion of pre-treated waste as Waste Derived Fuel (WDF) at the Proposed

Development for energy recovery. Both the baseline and the Proposed Development

scenarios are modelled twice to assess the impact of different starting proportions of

municipal solid waste (MSW) and commercial and industrial (C&I). This is to account for

the fact that the actual source of fuel for the Proposed Development (therefore the likely

mix of MSW and C&I) is not yet determined, as contracts will not be let until the key

consents for the Proposed Development are obtained. Two scenarios have therefore

been developed (A and B) to demonstrate the likely range of MSW/C&I mix that may

occur.

17B.3.2. The models used for this assessment have been set up to compare the scenarios

summarised in Table 17B.1.

Table 17B.1 Modelled Scenarios

Scenario

Scenario 1

(Baseline)

A 50/50 split between MSW and C&I sourced waste, pre-treated

with the residual fraction being disposed of to landfill.

B 80/20 split between MSW and C&I sourced waste, pre-treated

with the residual fraction being disposed of to landfill.

Scenario 2

(Proposed

Development)

A

50/50 split between MSW and C&I sourced waste, pre-treated

with the residual fraction being sent to the Proposed

Development as WDF.

B

80/20 split between MSW and C&I sourced waste, pre-treated

with the residual fraction being sent to the Proposed

Development as WDF

17B.3.3. The source of waste, the collection methodology and the transport impact of the waste

collection prior to pre-treatment is not included in the WRATE assessment as the specific

sources of waste that will result in the feedstock for the Proposed Development are not

yet known. However, because the sources of waste and the collection arrangements

would be the same for all of the scenarios modelled the impact of this element when

compared between the different scenarios would be neutral, as will the impact of the pre-

treatment process as this is also assumed to occur prior to disposal to landfill.

17B.3.4. Scenario 1A and 1B show the waste being pre-treated by removing a proportion of the

metal content and the remaining waste being disposed of to landfill without any further

materials recovery or recycling.

17B.3.5. Scenario 2A and 2B show the waste being pre-treated by removing a proportion of the

metal content and the remaining waste being sent to the Proposed Development as

WDF. Specific information about the Proposed Development has been used in the

WRATE model wherever possible. Where specific design information is not finalised,

assumptions have been made or input data taken from the defaults in the WRATE model.

A fuels assessment, considering possible sources of fuel and compliance with the waste

hierarchy, has been undertaken for the Proposed Development (Fuel Availability and

Waste Hierarchy Assessment, Application Document Ref. No. 5.9), and this has informed

the assumptions utilised within this analysis





Waste Composition

17B.3.6. As stated previously, and as further described in the Fuel Availability and Waste

Hierarchy Assessment (Application Document Ref. No. 5.9), it is not possible to define

the specific mix of MSW or C&I that might comprise the fuel for the Proposed

Development. It is also not possible at the current time to specify the geographical source

of the fuel or the specific average NCV.

17B.3.7. The average throughput for the Proposed Development is expected to be approximately

570,000 tonnes per annum. This tonnage has been modelled for this assessment on the

basis that this would represent the most likely throughput. In order to provide a robust

assessment the upper and lower average throughput tonnages have both also been

modelled.

17B.3.8. In order to accurately reflect the varying proportions of waste from these sources that the

Proposed Development might handle in the future, two scenarios have been modelled:

• Scenario 1A and 2A – 50/50 split between MSW and C&I sourced waste; and

• Scenario 1B and 2B – 80/20 split between MSW and C&I sourced waste.

17B.3.9. The default WRATE Municipal Solid Waste (MSW) composition for England has been

used for the MSW composition in the models. The composition of the C&I waste has

been based on the data from a study undertaken for the Environment Agency Wales in

2007 (Ref. 17B-1).

17B.3.10. The WRATE default MSW composition has been used in this assessment as the MSW

sources for the Proposed Development are not known. The MSW composition is as

shown in Table 17B.2.

Table 17B.2 MSW Composition

Waste Type % Composition

Paper and Card 23.99

Plastic Film 3.81

Dense Plastic 6.17

Textiles 2.79

Absorbent hygiene products 2.34

Wood 3.60

Combustibles 6.09

Non-combustibles 2.66

Glass 7.89

Organic 31.59

Ferrous Metal 3.06

Non-ferrous metal 1.32

Fine material <10mm 1.98

Waste Electrical and Electronic Equipment (WEEE) 2.23

Specific Hazardous Waste 0.48

Processed Materials 0

Non-MSW waste 0





17B.3.11. The composition of the C&I sourced waste is shown in Table 17B.3. The source of the

C&I Composition is the Environment Agency Wales I&C Waste Analysis Study (Ref. 17B-

1). The composition has been slightly altered in places as follows, in order to comply with

the waste input categories of the WRATE model:

• 0.1% biodegradable industrial sludge reallocated as fines;

• the total percentage composition in the data totals 99.6% therefore an additional 0.4%

has been added to the fines; and

• there is no option to input “black sack residual waste” into WRATE so the 0.6% black

sack residual waste has been reallocated as “other combustibles”.

17B.3.12. The resulting C&I waste composition is shown in Table 17B.3.

Table 17B.3 C&I Waste Composition

Waste Type % Composition

Paper and Card 32.2

Plastic Film 7.0

Dense Plastic 7.7

Textiles 1.6

Absorbent hygiene products 0.1

Wood 5.6

Combustibles 11.4

Non-combustibles 6.0

Glass 3.5

Organic 14.9

Ferrous Metal 3.6

Non-ferrous metal 0.8

Fine material <10mm 3.9

WEEE 1.1

Specific Hazardous Waste 0.6

Processed Materials 0

Non-MSW waste 0

17B.3.13. The total tonnage of waste input in the model is a function of the amount of waste which,

after pre-treatment would equal the proposed throughput of the Proposed Development.

Because the input waste composition varies between the A and B scenarios (as a result

of the different proportions of MSW and C&I modelled) a different tonnage of material is

recycled from each waste stream at the pre-treatment stage. The recovery of metals from

the waste arising is set at 84% for non-ferrous recovery and 88% for ferrous recovery. As

a result of this the total volume of input waste modelled has been slightly adjusted so that

both scenarios 2A and 2B show circa 570,000 tonnes sent to the Proposed Development

after pre-treatment. The total input waste modelled in Scenario 1A and 2A is 601,500

tonnes with 570,044 being sent to the Proposed Development. The total input waste

modelled in Scenario 1B and 2B is 603,300 with 570,088 being sent to the Proposed

Development.





Waste Pre-treatment

17B.3.14. Waste that is sent to the Proposed Development will have undergone some

processing/pre-treatment to refine its composition. For the same reasons set out

previously regarding fuels composition and NCV value, it is also not possible to define

specifically what pre-treatment will occur prior to the fuel arriving at the Site as this will

depend on the nature of the contracts eventually let for the Proposed Development.

17B.3.15. Based on the discussions and agreements reached to date for the multifuel facility

currently under construction (FM1), a basic pre-treatment process has been assumed for

the WRATE analysis. This is based on the experience of FM1 that remaining fuel

contracts are likely to involve relatively simple Material Recycling Facilities (MRF) rather

than more complex MRFs or Mechanical Biological Treatment (MBT) facilities. The

simplest option within the WRATE model that aligns with this assumption is a simple MBT

pre-treatment process (noting this is not full MBT, purely the pre-treatment aspect of that

option).

17B.3.16. The pre-treatment process used for all of the modelled scenarios shows a proportion of

the metals (ferrous and non-ferrous) being extracted from the input waste and recycled. A

proportion of the WEEE waste is also removed and sent for recovery. The pre-treatment

process modelled is a WRATE pre-treatment process for a MBT facility. Some of the MBT

facilities in WRATE require the user to model a separate pre-treatment process before

the user can model an MBT. The process used in this model is the ‘MBT crushing and

metals GENERIC process’. This would usually precede an MBT process but in this case

has been used as a stand-alone process for metals removal.

17B.3.17. The pre-treatment process modelled has been included in both the scenarios showing

waste being sent to the Proposed Development and waste being disposed of to landfill.

This results in a more conservative assessment when comparing the Proposed

Development to the baseline scenario as the benefit of the metals recycling is attributable

to both scenarios and not just to the Proposed Development.

17B.3.18. The pre-treatment process receives both the MSW and the C&I waste and producing just

over 570,000 tonnes of residuals with the following compositions:

Table 17B.4 WDF Composition – Scenarios 2A and 2B

Waste Type Composition – Scenario

2A (%)

Composition – Scenario

2B (%)

Paper and Card 29.65 27.13

Plastic Film 5.70 4.71

Dense Plastic 7.32 6.85

Textiles 2.32 2.70

Absorbent hygiene products 1.29 2.00

Wood 4.85 4.23

Combustibles 9.23 7.57

Non-combustibles 4.57 3.52

Glass 6.01 7.42

Organics 24.53 29.88

Ferrous Metal 0.43 0.41

Non-ferrous Metal 0.18 0.21





Waste Type Composition – Scenario

2A (%)

Composition – Scenario

2B (%)

Fine Material <10mm 3.10 2.50

WEEE 0.26 0.32

Specific Hazardous Household 0.57 0.53

Transport

17B.3.19. Transportation of the waste from source (i.e. collection point) to the pre-treatment facility

has not been modelled as fuel contracts have not yet been let, therefore this is not

currently known. For the purposes of comparing the Proposed Development as a route

for waste management in comparison to the disposal of the same waste to landfill any

transportation distance between the sources of the waste and the pre-treatment of the

waste would be the same for all scenarios and so comparatively the impact would be

neutral.

17B.3.20. The waste in both scenarios 2A and 2B is modelled as being transported 160 km to the

Proposed Development from the pre-treatment process. Transport is by intermodal road

transport (max capacity of 17.56 tonnes), 10% of the journey has been modelled as being

by urban roads and 90% by motorway. This assumption is based on the work undertaken

as part of the Fuel Availability and Waste Hierarchy Assessment (Application Document

Ref. No. 5.9) regarding possible geographical location of fuel. It should be noted,

however, that this study assumes a maximum distance to site of around 160 km whereas

for the assessment purposes a worst case has been adopted of an average travel

distance of 160 km. This is likely to result in an over-estimate of carbon emissions of

transportation but accounts for the uncertainty associated with possible locations of fuel.

17B.3.21. The transport assessment for the Proposed Development has been undertaken on the

basis that the HGVs used to transport the fuel to the plant will have a capacity of

22 tonnes. The largest capacity vehicle available in WRATE is 17.56 tonnes and this has

therefore been used in the model in the absence of a larger vehicle type. This means that

the number of journeys factored into the model by WRATE for the same tonnage of fuel

will be higher and therefore carbon emissions are also over-estimated by this factor.

17B.3.22. Transport in the baseline scenarios (1A and 1B) is modelled as being by intermodal road

transport to a landfill 100 km away with 10% of the journey by urban roads and 90% by

motorway. As the sources of waste are not yet known the distance from source to landfill

is an assumed distance.

Recycling

17B.3.23. The ferrous, non-ferrous metal outputs from the pre-treatment process have been

modelled within WRATE as a direct off-take; as opposed to utilising a transport function

as an intermediary. The process has an internal calculation which approximates transport

to a recycling centre, and therefore does not need a dedicated transport option, the

ferrous metal, non-ferrous metal and WEEE is all allocated as being transported 50 km to

a recycling/recovery facility.





Table 17B.5 Summary of Recyclables

Outputs for Recycling Tonnes

Scenario 1A and 2A

Ferrous metal 17,606

Non-ferrous metal 5,337

WEEE 8,513

Scenario 1B and 2B

Ferrous metal 16,802

Non-ferrous metal 6,138

WEEE 10,272

Energy Recovery – Proposed Development

17B.3.24. The energy recovery process depicted within WRATE is a ‘Flexible Energy from Waste

Process’. This process allows the WRATE user to define a variety of different parameters

in relation to gross heat and electrical efficiencies, the assumed method of power off-take

(electricity, Combined Heat and Power (CHP) and heat only), the flue gas cleaning and

reduction systems, and the recovery rate of ferrous and non-ferrous metals at the grate.

These variable parameters therefore focus on the key processes and the outputs with the

greatest environmental impacts.

17B.3.25. The process properties used in this model have been selected on the basis of the

available information about the Proposed Development as set out in Chapter 3 The

Proposed Development of the ES. This has been informed by the concept design work

undertaken for the project to date. The recovery type has been selected as ‘electrical

only’ as although the plant is CHP ready there is currently no end user identified for the

heat off-take.

17B.3.26. The gross electrical efficiency for the Proposed Development is expected to be 29%, and

this has been assumed for the purposes of the model.

17B.3.27. The proposed flue gas treatment system will consist of Selective Non-Catalytic Reduction

(SNCR) of NOx, activated carbon injection, dry lime scrubbing and fabric filters. The

ferrous metal and non-ferrous metal recovery at the grate has been specified as 0% and

the metal content of the waste is shown to pass straight to the bottom ash. The bottom

ash from the Proposed Development is modelled as being sent to a bottom ash recycling

facility where the metals are recovered and the ash is used to produce incinerator bottom

ash (IBA) aggregate. It may be that once operational there is some ferrous metals

recovery undertaken on site prior to the ash being transported elsewhere. In scenario 2A

118,016 tonnes of IBA is sent for recycling and in Scenario 2B 119,588 tonnes of IBA is

sent for recycling.

Landfill

17B.3.28. The flue gas treatment (FGT) residue from the Proposed Development will be classified

as hazardous waste and will be treated and disposed of to an appropriate landfill. A

default landfill site with a High-density Polyethylene (HDPE) liner and a HDPE cap is

used in the model.





Figure 17B.1 Scenario 2A

Figure 17B.2 Scenario 2B





17B.4. Results

17B.4.1. Tables 17.6 and 17.7 present the global warming potential results of the WRATE

modelling for all of the scenarios.

17B.4.2. Where the model results show a negative unit value this is indicative of a process

displacing conventional energy or electricity or material use, therefore the process that

places the least burden on the environment (in respect of each of the impact assessment

types) is that which shows the lowest or the most negative values.

Table 17B.6 Global Warming Potential (1A and 2A)

Impact

Assessments Unit Scenario 1A - Baseline

Scenario 2A –

Proposed

Development

Climate change

GWP 100a Kg CO2-eq 91,380,460 -138,335,797

Table 17B.7 Global Warming Potential (1B and 2B)

Impact

Assessments Unit Scenario 1B - Baseline

Scenario 2B –

Proposed

Development

Climate change

GWP 100a Kg CO2-eq 87,762,139 -145,888,738

17B.4.3. Both scenarios that feature the management of waste at the Proposed Development (2A

and 2B) perform better than the baseline scenarios.

17B.4.4. The WRATE model scenario 2A shows that the transfer of waste to the Proposed

Development presents significant carbon savings, of over 229 million kg CO2-eq in

comparison to the baseline (scenario 1A). The WRATE model scenario 2B shows that the

transfer of waste to the Proposed Development presents significant carbon savings, of

over 233 million kg CO2-eq in comparison to the baseline (scenario 1B). This

demonstrates that whilst the exact composition of fuel to be used by the Proposed

Development is not known, the Proposed Development presents significant carbon

savings when compared to the baseline for the likely range of composition.

17B.4.5. Figures 17B.3 and 17B.4 show the extent to which the elements of the different scenarios

contribute to global warming potential. The graphs clearly show the burdens and avoided

burdens (negative and positive values) and how these compare to each other.


Document Ref:6.4.24



Figure 17B.3 Global Warming Potential (1A and 2A)


Document Ref:6.4.24



Figure 17B.4 Global Warming Potential (1B and 2B)





17B.4.6. Figures 17B.3 and 17B.4 show that the major carbon impact is the landfilling of the waste

as modelled in the baseline scenarios 1A and 1B. The metals recycling in all of the

scenarios is the dominant beneficial element in terms of carbon impact (shown in yellow)

with the additional recycling of IBA from the Proposed Development increase this benefit

in scenarios 2A and 2B.

17B.4.7. The treatment and recovery process (shown in light blue) incorporates both the pre-

treatment process and the Proposed Development process impacts. It can be seen here

that in scenario 1A the impact of the pre-treatment process is a positive figure – most

likely to be predominantly related to the energy requirement of that process. In contrast

scenario 2A also includes this burden but this offset by the Proposed Developments

process which is a net producer of energy and which reduces carbon emissions by

displacing energy that would otherwise be generated in part from fossil fuels.

17B.4.8. The table below summarises the global warming potential of each element of the

Proposed Development scenarios (2A and 2B) in kg CO2-eq.

Table 17B.8 Global Warming Potential

Project Headline Indicators Scenario 2A

(kg CO2-eq)

Scenario 2B

(kg CO2-eq)

Transportation

Transport to the Proposed

Development from pre-

treatment

20,495,551 20,496,814

Recycling

Non-ferrous metal recycling -57,214,349 -65,808,122

Ferrous metal recycling -28,575,656 -27,270,617

Incinerator Bottom Ash

recycling -7,967,847 -8,903,713

Treatment and Recovery

Pre-treatment process 17,823,519 17,876,856

Proposed Development -82,967,583 -82,350,870

Landfill

Landfill of FGT residues

from the Proposed

Development

70,568 70,914

Total -138,335,797 -145,888,738





17B.5. Model Analysis

17B.5.1. There are a number of unknowns associated with the feedstock for the Proposed

Development. Depending on the average NCV of the feedstock sourced the Proposed

Development will accept a range of tonnages, the highest throughput being 675,000 tpa

and the lowest throughput being 425,000 tpa.

17B.5.2. In order to provide a thorough assessment of the carbon impacts associated with the

Proposed Development, the highest and lowest tonnages have also been modelled for

comparison with the most likely throughput of 570,000 tpa. It should be noted that the

results presented in this section are as a result of changes made to the tonnage of WDF

being sent to the Proposed Development – no changes have been made to the WDF

composition, the pre-treatment process or any of the other associated processes. No

changes have been made to the baseline scenario (disposal to landfill) with the exception

of the total tonnage of waste being dealt with.

Variation to annual throughput - 425,000 tonnes

17B.5.3. 425,000 tonnes per annum throughput has been modelled for both compositions of input

waste i.e. a 50/50 split between MSW and C&I waste and an 80/20 split between MSW

and C&I waste.

Table 17B.9 Global Warming Potential 425,000 tonnes (50/50 MSW/C&I)

Impact


Scenario 2A –

Proposed

Development

Climate change

GWP 100a Kg CO2-eq 73,293,322 -103,134,232


Impact


Scenario 2A –

Proposed

Development

Climate change

GWP 100a Kg CO2-eq 65,411,197 -108,770,197





Variation to annual throughput - 675,000 tonnes

17B.5.4. 675,000 tonnes per annum throughput has been modelled for both compositions of input

waste i.e. a 50/50 split between MSW and C&I waste and an 80/20 split between MSW

and C&I waste.


Impact


Scenario 2A –

Proposed

Development

Climate change

GWP 100a Kg CO2-eq 116,408,852 -163,804,311


Impact


Scenario 2A –

Proposed

Development

Climate change

GWP 100a Kg CO2-eq 103,904,954 -172,739,989

17B.5.5. Figures 17B.5 – 17B.8 show the breakdown of the results for the varying tonnages and

waste compositions considered.





Figure 17B.5 Global Warming Potential 1A and 2A (425,000 tpa)





Figure 17B.6 Global Warming Potential 1B and 2B (425,000 tpa)





Figure 17B.7 Global Warming Potential 1A and 2A (675,000 tpa)





Figure 17B.8 Global Warming Potential 1B and 2B (675,000 tpa)





Pre-treatment

17B.5.6. One of the main elements of the assessment that could vary considerably is the pre-

treatment of the waste prior to transportation to the Proposed Development. At present

this a relative unknown although it is likely that the waste will be sourced from a number

of different facilities that can produce a residual fraction or WDF suitable for energy

recovery at the Proposed Development.

17B.5.7. The use of different pre-treatment facilities will result in different impacts when modelled

in WRATE, variation will include energy utilised by the process, tonnages and range of

recyclables recovered from the incoming waste, the resulting composition of the waste

sent to the Proposed Development and the distances between the facilities and the

Proposed Development. All of these things have knock-on implications for the other

elements of the assessment and the overall results. A number of iterations of this model

have been tested with different pre-treatment facilities modelled resulting in different

compositions of WDF to be treated at the Proposed Development. All of the test models

with different waste pre-treatment processes performed better than the baseline scenario

of sending the same waste for disposal to landfill.

Transport Distances

17B.5.8. The transportation of waste has a relatively minor carbon impact in comparison to the

other elements of the assessment. The distance of 160 km for waste to be sourced is a

‘worst case’ distance and so a sensitivity analysis has been undertaken to determine how

much of a difference different journey distances would make to the overall global warming

potential assessed by WRATE. Table 17B.13 below shows how the impact of the

transport element of scenario 2A varies over a range of different distances.

Table 17B.13 Transport Distance Sensitivity

Project Headline Indicators Distance

(km)

Scenario 2A

(kg CO2-eq)

Transport to the Proposed Development

from pre-treatment

(Intermodal Road Transport with max

capacity of 17.559 tonnes. Total waste

tonnage transported: 570,044 tonnes)

160 20,495,551

150 19,214,579

140 17,933,607

130 16,652,635

120 15,371,663

110 14,090,691

100 12,809,719

80 10,247,776

50 6,404,860

20 2,561,944

10 1,280,972

1 128,097

17B.5.9. For the transport mode used in the WRATE assessment the carbon impact is

approximately 128,097 kg CO2-eq for every km travelled (for total waste transported). On

the basis that the maximum capacity of each vehicle used is 17.559 tonnes this equates

to roughly 0.22 kg CO2-eq per tonne of waste per km (i.e.3.94 kg CO2-eq per vehicle per





km). As previously mentioned, the overall impact assessed for the transport element of

the scenarios is likely to be greater in the models than in reality as the vehicles that will

be used to transport waste will have a greater capacity and so the number of vehicles

overall will be less.

Proposed Development Outputs

17B.5.10. Scenario 1B and 2B both show the outputs produced by the Proposed Development;

FGT residue and IBA.

Table 17B.14 Proposed Development Outputs

Outputs for Recycling Tonnes

Scenario 2A FGT Residue 25,773

IBA 118,016

Scenario 2B FGT Residue 25,899

IBA 119,588

17B.5.11. These figures are somewhat higher than those anticipated for the Proposed Development

(between 76,000 and 116,000 IBA anticipated and between 21,700 and 22,500 FGT

residue anticipated – as outlined in Chapter 3 The Proposed Development) however

the outputs in WRATE are a direct function of the type of facility modelled and the waste

input into that facility. The fact that the outputs are slightly higher in the model provides a

conservative assessment as the related impacts will be higher than are expected in

reality.

17B.5.12. The scenarios presented in this report and utilised within Chapter 17 Sustainability

within the ES have been selected as they represent the lower end of the likely range of

carbon savings to be achieved by the Proposed Development to account for uncertainties

at the current stage. This therefore represents a ‘worst case’ assessment of this particular

benefit, and the final savings achieved may be somewhat higher.





17B.6. Conclusions

17B.6.1. Based on the outputs from the above assessments, the environmental impact of the

Proposed Development against a baseline of disposal of waste without treatment to

landfill can be summarised as detailed in Table 17B.15.

Table 17B.15 Summary of Results

Scenario Waste Management Route Total Kg

CO2-eq

Kg CO2-eq/tonne

of waste

1A Baseline – disposal of waste to landfill 91,380,460 152

2A Production of WDF for combustion at

the Proposed Development -138,335,797 -230

Scenario Waste Management Route Total Kg

CO2-eq

Kg CO2-eq/tonne

of waste

1B Baseline – disposal of waste to landfill 87,762,139 145

2B Production of WDF for combustion at

the Proposed Development -145,888,738 -242

17B.6.2. The assessment undertaken allows for the comparison of the Proposed Development

with an alternative ‘do-nothing’ baseline scenario where the same waste that would be

treated at the Proposed Development is disposed of to landfill.

17B.6.3. As outlined previously, the marginal energy mix used in this assessment is the WRATE

default for 2020 – 33.8% coal, 4.2% gas and 62.0% gas CCGT. The WRATE results are

therefore likely to indicate a higher benefit than if the energy displaced was of a lower

carbon intensity (i.e. 100% gas CCGT displacement as indicated in the Defra guidance

(Ref 17B-1)) however the Proposed Development would still be of net benefit when

considering the whole lifecycle assessed within the WRATE assessment.

17B.6.4. The WRATE assessment demonstrates that the treatment of waste at the Proposed

Development is environmentally preferable to the disposal of waste to landfill in terms of

global warming potential.





17B.7. References

Ref 17B-1 Energy from waste – A guide to the debate; Defra; February 2014 (revised

edition)

Ref 17B-1 2 Wales I&C Waste Analysis Study; Environment Agency; 2007

appendix 17b - wrate assessment - planning inspectorate · sncr selective non catalytic reduction...

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