38215 for biomass 3 lr
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Biomass heating:a guide to easibility
studies
Introduction to feasibility
studies
What is biomass?
Types of biomass boilers
Heating system selection
Surveying a site for a
biomass installation
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This guide provides a brie introduction to biomass boilers ollowed bya stepby-step guide to carrying out the technical aspects o a biomass
easibility study. The guide is concerned with the use o logs, wood
chips and wood pellets only, these being the principal uels used in
biomass heating systems in the UK.
This, and the two accompanying guides, Biomass heating: a guide to
small log and wood pellet systems and Biomass heating: a guide to
medium scale wood chip and wood pellet systems, are concerned with
low temperature hot water boilers o up to 5 MW operating at a
maximum fow temperature o 95 C.
Introduction tofeasibility studies
What is
biomass?Biomass or burning as a uel includes wood (Figure1), energy crops, agricultural crop residues, woodmanuacturing by-products and arm animal litter.Although burning biomass releases carbon dioxide(CO2) to the atmosphere, this is principally oset by theCO2 absorbed in the original growth o the biomass, orcaptured in the growth o new biomass which replacesthe materials used when it is sustainably sourced.Using biomass or heating thereore results in verylow net liecycle carbon emissions relative to
conventional sources o heating, such as gas, heatingoil or electricity.
The selection o the uel to be used can be complex asit depends on many actors. While cost is a key driveror uel selection, the space available or uel storage,access or uel deliveries and the method o deliveryare all key considerations. The wooduel heatingsystem selection owchart (Figure 4, page4) provides guidance on choosing thetype o heating system and thetype o uel to be used.
Wood suitable orharvesting as uel(Forestry Commission).
Figure 1
Types of
biomass boilersPellet boilers and stoves
Pellet boilers and stoves (Figure 2) range in sizerom a ew kilowatts (kW), or houses or smallcommercial buildings, to megawatt (MW) size unitsor district heating systems. Pellet systems aregenerally the most responsive o the biomassboilers, have the simplest controls and are theclosest to ossil uelled boilers in terms omaintenance and operating intervention. Pelletstoves and small pellet boilers are covered in detailin Biomass heating: a guide to small log and woodpellet systems, while larger boilers are covered inBiomass heating: a guide to medium scale wood chipand wood pellet systems.
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Log stove (Forestry Commission).
Figure 3
Log stoves
Traditional log stoves (Figure 3) provide radiant heatto a room. They need to be manually ed with uel asrequired to maintain the heat output, and achievesignifcantly higher efciency (around 70%) thanopen fres. Some log stoves incorporate a boiler toprovide hot water or domestic purposes or to heatradiators. Some may also incorporate a hob and/oroven or cooking. As mentioned, log stoves generateradiant heat into the room in which they stand andit is not possible to provide hot water without alsoheating this room.
Batch type log boilers
Log boilers also require wood to be manually loadedinto the boiler, making them suitable or housesor small applications where labour is available. In
contrast to a log stove, however, they are typicallyloaded just once or twice a day, and this batch ologs is then burned in one go, at high temperatureand efciency. This means that log boilers requirea large water storage cylinder (a buer tank,accumulator tank or thermal store) to capture theheat produced. Log stoves and boilers are coveredin detail in Biomass heating: a guide to small log andwood pellet systems.
Wood chip boilers
To date, wood chip boilers have dominated the
commercial market in the UK. Fuelled by woodchips, these boilers can be confgured to run ona wide range o dierent uel specifcations withmoisture contents rom 15% to 50%
1. Boiler sizes
range rom 40 kW to power station sized boilerso 100 MW and more. Boiler responsiveness isdetermined by the uel moisture content that theboiler is designed to accept; in general the wetterthe uel, the less responsive and efcient the boiler.Wood chip boilers are covered in Biomass heating:a guide to medium scale wood chip and wood pelletsystems.
Pellet stove (RBAN).
Figure 2
1 All moisture contents quoted in this publication are on a wet basis, that is Weight o water in a given sample
Total weight o the samplex 100 = MC% (wet basis).
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START
YesNo
YesYes1 or 2rooms
Throughoutthe house
Throughoutthe house
Automaticpelletboiler
fed from a fuelhopper or silo
supplying adistrict heating
network.7
Automatic chipboiler fed from
a hopper orsilo supplying a
district heatingnetwork.7
Automaticpelletboiler
fed from a fuelhopper or silo.7
Small automaticpelletboiler
or pellet stovewith integrated
hot water.7
Pelletstove(s)
withoutintegrated
boiler.7
Logboiler orstove withintegrated
boiler.7
Traditional logstove(s) without
integratedboiler.7
No
Woodfuelmay not beappropriate
for you atthe moment.
Is thereaccess for apneumatic
deliveryvehicle
and bulkstorage?2, 5
Wood pellets:
Lower capital cost
Higher fuel cost
Suitable for all
scales of heat use High density more
compact fuel
Wood chips:
Higher capital cost
Lower fuel cost(with the potentialfor self-supply)
Suitable for largeheat users
Low density, largestore required
Automatic chipsystem fed from
a fuel hopperor silo.7
Are you willingto manuallyhandle logs
daily?
Are you willingto manuallyhandle bags
of pelletsweekly?
Is there a localsupplier whocould sell you
individual bagsof pellets?
Woodfuelmay not beappropriate
for you at themoment.
How big is
the area to beheated?
Is there accessand space tostore a pallet
of baggedpellets?6
How big is
the area to beheated?
Is there accessand space to
store a transitvan load of
logs?
Is the buildingsmaller thana large farm
house?4
Is there goodsite access
and plenty ofstorage space?
Is there accessfor pneumatic
deliveryvehicle and
space for bulkstorage?2, 5
Would thenoise frompneumaticdelivery bea barrier to
installation?
Woodfuelmay not beappropriate
for you at themoment.
Choose mostappropriate
fuel type.
Will the heatbe supplied tomore than one
building?
Is the sitea single
building?
The appliancewill need to beon the ExemptAppliances list.1
Would thisstill be a
problem with
less frequentdeliveries?3
Wouldincreased
vehiclemovements for
fuel deliverybe a barrier toinstallation?2
Will the heatbe supplied tomore than one
building?
1 or 2rooms
No
Yes
Yes
NoChip
YesYes
Pellet
No
No
No
No
No Yes
YesYes
No
No
Yes
No
Yes
Yes
NoYes
Is the sitein a smoke
control area?1
Yes
No
. I i i i i. . . i
i i .
. i i i i i i , ii . i . i i
. i i i i. i i i i i i i .
i i i i i .
. i i i i i i i .
. i i .
. i i i ii . . i i
i i i i , i ii .
. i . . i .
. .
. i i i i i . i i i i .i i i I i
NoNo
YesYes
Yes
Heating system selectionThe owchart shown in Figure 4 is designed to assist with the selection o the most appropriate combinationo wooduel and heating boiler or stove.
Wooduel heating systemselection fowchart.
Figure 4
1. Inormation on smoke control areas and exempt appliances is available athttp://smokecontrol.dera.gov.uk/ (On larger systems grit and dust arrestors maybe required by the local authority.)
2. A small pellet delivery vehicle is typically rigid, measuring 10 m long x 3 m wide
x 3.5 m high. Pellets can also be transported in a 31 tonne articulated lorry. Pelletscan be delivered pneumatically over a distance o around 20 m to inaccessiblepellet stores. Chip is delivered in a variety o vehicles and trailer arrangements.Requirements or these are best discussed with uel suppliers in your area.
3. Pellet deliveries require approximately 25% o the requency o deliveries or chip.
4. Assumed to require a 40 kW boiler.
5. Pellet storage requirement is assumed to be 5 tonnes or a domesticsetting (or approximately 7.5 m3 at 670 kg/m3). Wood chip bulk density anduel storage requirement will vary with moisture content, however the bulk
density o chip will always be much lower than that o pellet.See www.biomassenergycentre.org.uk or more details.
6. 1012 bags.
7. A list o boiler suppliers is available at www.microgenerationcertifcation.org/Home+and+Business+Owners/Microgeneration+Installers/Biomass
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Surveying a sitefor a biomass
installationThe process o deciding whether it is possible toinstall a biomass boiler, and whether a biomassboiler is suitable, comprises 10 stages or steps.The 10-step process takes the reader through thetechnical stages o easibility to the point where itis worthwhile proceeding with a ull economic andenvironmental analysis o a project. Figure 5 is asummary o this 10-step technical easibility process.
STEP 1
Do I have enough space: part 1?
While it is not possible to determine preciselywhether sufcient space is available prior tocarrying out a boiler and uel sizing exercise,the frst step must be to carry out a preliminaryassessment o the physical space available. Theollowing checklists should enable this decision tobe made.
A biomass boiler:
Will be physically much larger than a ossil uelequivalent boiler.
Will have a much larger ootprint requiringclearances to allow or boiler tube cleaning andeed auger and ash auger extraction.
Will usually be taller and may require accessrom above.
May not ft into the space available in an existingboiler house.
It is also worth considering whether it is moreeective to install a biomass boiler to deal with a baseheat load, with a secondary boiler to provide backupand additional capacity or peak load. However, thiswill entail additional space requirements.
Space external to the boiler house will be requiredor a uel store (or example Figure 6) and, i thebiomass boiler cannot be installed in the existingboiler house, an extension or a new boiler house willbe required. You should assess whether there is:
Space to construct an extension to an existingboiler house or to construct a new boiler house irequired.
Space to construct a uel store contiguous withthe boiler house.
Access or a delivery vehicle, or could the vehicleget to within 20 m o the uel store?
STEP 2
Establish whether a fuel supply isavailable
A list o wooduel suppliers is available onthe Biomass Energy Centre website at: www.
biomassenergycentre.org.uk It is important thatthe correct standard o uel is used to ensurereliable and efcient operation o the boiler.
STEP 1Make a preliminary estimate o whetherspace is available or a boiler and uel store
STEP 2 Establish whether a uel supply is available
STEP 3Determine whether uel delivery vehicleaccess is available
STEP 4Determine whether the building or process issuitable or conversion to biomass
STEP 5 Determine the size o boiler required
STEP 6 Determine the size o uel store required
STEP 7Determine the exact space required or boilerand uel store
STEP 8Identiy i the boiler is to be installed in asmoke control area
STEP 9 Determine the height o chimney required
STEP 10Check that compliance with statutoryrequirements is possible
Ten-step technical easibility process.
Figure 5
Fuel store or wood chips close to boiler house(Forestry Commission).
Figure 6
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STEP 3
Fuel delivery and reception
Having previously established that a uel deliveryvehicle could access the site, the method o ueldelivery and reception into the uel store needs to beconsidered. The ollowing two checklists should
assist with decisions on uel delivery and reception.
If wood chip is the preferred fuel:
The most economical method o delivery is bytipping into a silo below ground level or onto awalking oor.
I sloping ground is available a semi-undergroundsilo can be constructed with minimal excavation.
I sloping ground is not available and excavationo an underground silo would be problematic ortoo expensive, it may be possible to build up a
ramp so uel can be tipped in rom above;alternatively a walking oor in the uel storagebuilding may be the best option.
The walking oor needs to be designed to takethe weight o a delivery vehicle, or uel can betipped onto a concrete oor in the uel storagebuilding and loaded onto the walking oor using amechanical shovel.
The uel storage building will need either a verytall roo to allow a tipping vehicle to tip within thebuilding or a sliding roo.
An alternative method o uel delivery and storageis to use a hook lit bin system where uel isdelivered in a container by a hook lit deliveryvehicle, and the container becomes the uel siloconnected directly to the uel extraction system.
Another method o wood chip delivery is or adelivery vehicle to tip into the reception trough oa wood chip blower which can deliver chips over ashort distance by pneumatic conveying.Unortunately, this method o uel delivery is verynoisy and may not be suitable or all locations. Itis also slow which drives up uel cost.
In small quantities, delivery by bag is possible.However, this system usually requires a crane-equipped delivery vehicle to swing bags over anabove-ground storage hopper. As this hasundesirable saety implications or the operator,who has to untie the bottom o the bag to release uel
into the hopper, this method is not recommended.
If wood pellet is the preferred fuel:
Bulk pellet delivery can be made by tipping orpneumatic conveying. For small installations
pellets can also be bought bagged on a pallet. I pellets are delivered by tipping, the considerations
described above or wood chip delivery by tippingalso apply.
For pneumatic delivery, specially equippedvehicles are used containing both uel deliveryand dust extraction ans.
A pellet silo designed to accept uel by pneumaticconveying will need to be equipped with twocamlock connectors at high level attached toductwork. One duct is used or pellet supply while
the other extracts dusty air rom the silo. Dustextraction is essential to prevent the concentrationo dust orming an explosive atmosphere in thesilo, and also to relieve pressure in the silo toenable the delivery an to deliver pellets.
A specialist pellet delivery vehicle can typicallyblow pellets over a distance o around 20 mhorizontally, or up to 12 m vertically i a verticalgrain-type silo is used.
The Carbon Trust publication, Biomass heating: apractical guide for potential users, contains
comprehensive inormation on uel delivery andstorage (see Sources o urther inormation, page 12).
STEP 4
Is my building suitable for conversionto biomass?
A number o actors dispose a building or processtowards the use o a biomass boiler to provide heat.
For buildings these include:
The building has an existing low temperature hotwater heating system. The existing boilers are lieexpired or in need o replacement in the nearuture. The existing boilers are o the single-passor atmospheric gas type. The building is not onmains gas.
Large carbon savings are required to meettargets. The building is old and o heavyweightconstruction, e.g. listed buildings, most historicbuildings, solid sandstone or limestone buildings,or buildings which would otherwise be difcult toinsulate. The building is a new build and theopportunity exists to integrate biomass into the
building rom the outset.Reasons or not installing biomass in a building arethe opposite o many o the actors listed above. Inparticular, i a building does not have an existing wetheating system or an air heating system based onair handling units with hot water eeding the heatingcoils, it may not be suitable or conversion or theconversion may be very expensive.
With respect to industrial processes, the reasons orinstalling a biomass boiler include:
The industrial process uses low temperature hotwater.
The installation o a biomass boiler woulddisplace steam use or hot water generation.
Mains gas is not available.
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STEPS 5 and 6
Sizing a biomass boiler and biomassfuel store
The sizing o a biomass boiler is a complex taskeven or an experienced building services engineer,and it will be dierent or every boiler, based on the
heat load demand pattern and the winter peak load.The sizing o boilers, buer vessels and uel storesis best let to experienced designers and boilersystem installers, and a suitably qualifed designengineer or contractor should be engaged or thispurpose.
BEC has a number o downloadable tools writtenby Forest Researchs Technical Development unitto provide support in a number o dierent biomasscalculations. This includes a simple spreadsheet-based tool designed to help calculate boiler sizes2.
The Carbon Trust has also published biomass
system design sotware available as a reedownload rom their website3. This sotware hasbeen designed specifcally to address the issue ooversized boilers and undersized buer vessels. Itallows the designer to input data on the building orprocess to create a winter design day load curve,and then to size a boiler and buer combinationaccurately while minimising capital cost andmaximising carbon savings. It also allows or thesizing o a biomass uel store and a completeenergy, CO2 and fnancial analysis. This sotware isdesigned to be used by a competent engineer.
STEP 7
Do I have enough space: part 2?
Once the rating o the biomass boiler has beenestablished, the size o the buer vessel calculated,and a decision made on the number o days uelstorage required, it is possible to determine the sizeo boiler house and uel store needed. Connectinga biomass boiler into an existing heating systemcan be either directly into the system or via a heatexchanger. I directly connected, pressurisation and
expansion or the biomass boiler will be providedby the existing system, modifed as required.However, i you intend to operate the biomass boileras a separate hydraulic system, a heat exchanger(usually a plate heat exchanger) will need to beinstalled in the existing boiler house. The simplestway to do this is to remove an existing boiler and putthe heat exchanger in its place.
Bear in mind that it may also be desirable to retainan existing ossil uel boiler to provide peakingcapacity to allow the biomass boiler to be specifedto meet base load. This will allow it to operate within
2 www.biomassenergycentre.org.uk/portal/page?_pageid=74,373197&_dad=portal&_schema=PORTAL3 www.carbontrust.co.uk/emerging-technologies/current-ocus-areas/biomass/pages/biomass-tool.aspx (login required)
its modulation range or a greater part o the year,spending more time operating at higher output andefciencies. It may also be used to supply domestichot water in summer. This decision will inuencethe space required in the existing boiler house, and
potentially which o these options to adopt.
Boiler house space
There are a number o points that you need toconsider when calculating the space required or abiomass boiler house (Figure 7):
The orientation o the biomass boiler houserelative to the uel store.
The ootprint o the biomass boiler.
The ootprint o any additional boiler.
The clearance required to remove the ueleed system, requently an auger.
The clearance required to take out the ashremoval auger.
The clearance required to clean the boilerueways i an automatic ue cleaning system isnot installed.
Where to install a plate heat exchanger (irequired).
The signifcant space required or a buer vessel:this includes vertical space or a large stratifed
water store. The space required or expansion vessels.
Whether the existing heating system hydraulicconfguration needs to be changed to accepta biomass system, e.g. i headers need to beextended or replaced.
How the biomass boiler ue is to be confgured,and whether the space occupied by an existing orredundant ue could be utilised.
Adequate access to allow the installation orremoval o the boiler rom the boiler house.
Boiler house with biomass boiler(Forestry Commission).
Figure 7
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concentrations o particulate matters and NO2not being exceeded in a given area, approval or abiomass installation should be possible.
Emissions
The complete combustion o wood producesemissions o fne particulates, NO2 and carbondioxide (CO2), whereas the incomplete combustiono wood results in the release o carbon monoxide(CO), volatile organic gases, benzene and otherundesirable substances some o which arecarcinogenic. The emission o black smoke rom achimney is a good visible indicator o incompletecombustion.
In order to ensure the complete combustion owooduel, biomass boilers require the ollowingeatures:
An adaptive uel eed mechanism which adjuststhe amount o uel ed into the boiler in real timedepending on the instantaneous load on theboiler.
The monitoring o boiler ow and returntemperatures, and their use via a control systemto regulate the uel eed rate and the speed ocombustion air ans.
Separately controllable primary and secondarycombustion air (also tertiary air control on boilersabove about 5 MW).
A lambda sensor to monitor the oxygen content othe ue gas to ensure sufcient excess oxygen issupplied or complete combustion by regulatingsecondary (and tertiary) air ans.
NO2 is o particular concern because it is an irritantin the lungs. The overall air pollution index ora site or region is calculated rom the highestconcentration o the fve pollutants: NO2, SO2,ozone (O3), CO2 and particles
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Regulators generally divide particulate matter intotwo categories: PM10 and PM2.5:
PM10 are particles that are 10 micrometres orless in size. (For comparison, the width o ahuman hair is about 30-200 micrometres.) Thelarger o these particles are deposited in theupper airways beore they reach the lungs and
most do not travel urther into the body. PM10 arereleased by biomass combustion but also roma wide variety o other sources such as crushingand grinding operations, road dust, pollen, andmould spores.
PM2.5, or fne particles, are up to 2.5 micrometresin diameter. These particles come mainly romcombustion sources, including vehicles that burnpetrol or diesel, power plants and actories thatburn coal, oil, gas or biomass. These particlesalso occur naturally through orest or grass fres,and as organic molecules rom vegetation. This
category concerns scientists the most, becausethese tiny particles can slip past our bodiesdeences and end up deep in our lungs.
To avoid the production o black smoke rom abiomass boiler chimney the ollowing conditionsmust be met:
The boiler must operate within its turndown band,e.g. a 300 kW boiler with a 3:1 turndown ratiomust not operate i the load alls below 100 kW.Either the boiler must switch o, must enter aslumber mode, or it must operate with a buer
vessel in parallel to accept the excess energyproduced.
The moisture content o the uel must be withinthe range the boiler can accept. In particular, uelwith a moisture content above the acceptablerange will smoulder and invariably produce blacksmoke.
STEP 9
Chimney heights and the dispersion ofpollutants
The Clean Air Act requires the chimney height o abiomass boiler burning more than 45.4 kg/hour obiomass uel to be approved by the local authority.The local authority will need to be satisfed that theGuidelines on Discharge Stack Heights or PollutingEmissions have been ollowed (Technical GuidanceNote (Dispersion) D1: see Sources o urtherinormation, page 12). The owchart in Figure 8shows the process o ue selection.
START
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Flue height will be the boiler
manuacturers minimum fue height
or the requirements under Technical
Guidance Note (Dispersion) D1. 2
Flue height will be determined by
the building regulations.
Is the boiler
burning>45.4 kg
o uel per hour?
Boiler will
usually need
a grit and
dust arrestor
installed. 1
Does the boilerhave an induced
drat an?
Is the boiler
to be installed
in a smoke
control area?
Flue height wil be determined
by the boiler manuacturer.
Flue height will be determined by
Technical Guidance Note
(Dispersion) D1. 2
No
Is the rated
output o
the boiler
>50 kW?
Boiler must
be on the
Exempt
Appliances list.
Flue selection fowchart.
Figure 8
1. Grit and dust arrestors may not be required ithe local authority has been satisfed that theemissions will not be a nuisance or prejudicialto health.
2. Technical Guidance Note (Dispersion) D1: seeSources o urther inormation, page 12.
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STEP 10
Planning consent and other regulations
The Building Regulations
The Building Regulations contain provisions or soliduel boilers and stoves with a rated output up to 50 kW.The detail or the countries in the UK can be ound in:
England & Wales: Part J: Combustion appliances andfuel storage systems
Scotland: Sections 3 and 6 o the Technical Handbook -Domestic Handbook
Northern Ireland: DFP Technical Booklet L: 2006 Combustion appliances and fuel storage systems
The regulations cover air supplies to appliances, the size
and height o ues, permissible ue outlet positions, the
separation o combustible materials, ue linings,
freplaces, hearths and uel storage. The content o the
England, Wales and Northern Ireland Regulations is
essentially the same while that or Scotland is dierent
in some respects; at the time o writing, the Scottish
Government are developing guidelines on low carbon
equipment and building regulations.
The planning owchart (Figure 9) is a guide to theplanning and permitting process in the dierentcountries o the UK. Guidance documents are listed inSources o urther inormation, page 12.
Waste wood, the Waste Incineration Directive
and Environmental Permitting
The Environment Agency has issued the ollowingdefnition o waste wood: Waste is any wood that is nota orestry material, tree surgery residual, or a by-product o processing clean virgin timber (cleansawdust and ocuts).
Depending on the type o uel used, and i the boiler isover 400 kW, the Environmental PermittingRegulations 2011 have to be taken into account. A keyactor is whether the uel to be used is considered awaste and, i so, is it waste wood exempt rom theWaste Incineration Directive (WID)? Boilers ratedbetween approximately 400 kW and 3 MW can burnwaste wood such as MDF, chipboard and clean palletwaste, however the local authority environmentalhealth ofcer should be consulted on what conditionsneed to be applied, and it is advisable to consult therelevant environmental agency.
The local authority will require urther inormation onthe technical details and likely environmental impacts.They may also stipulate continuous monitoring o uegases, but this may simply mean handing over data tothem at regular intervals. I the boiler is over 3 MW therelevant environmental agency must be consulted.
START
Yes
Yes
Yes
Yes
No
No
No
No
No
No
Are youintending to
use waste woodas uel? 1
Reer to the
ue selectionowchart
(Figure 8, page 9).
The PPC regulations mayapply. Consult your national
regulatory body. 2
Is the thermalinput to your
heating system>20 MW?
Is the boilerrated at45.4 kgo uel per hour?
Boiler must beon the Exempt
Applianceslist. 5
The PPC regulations will apply. A
licence will be required rom yournational regulatory body. 2
The Building Regulations apply.
England & Wales: Part J
Scotland: Technical Handbooks 3 and 6
Northern Ireland: DFP Technical Booklet L
Check with local authorityenvironmental health concerning NOx
and particulates.
Consult local planning authority.
Yes
Yes
No
Grit and dust arrestors may berequired i the local authority hasbeen satisfed that the emissions
will not be a nuisance or prejudicialto health.
Is the uelWID exempt?
Fuel must beburnt in a WID
compliant system. 1
YesIs theboiler rating>400 kW?
Is the boiler
located in asmoke control
area? 4
Is the boilerlocated in an
Air QualityManagement
Area? 3
Yes
No
1. See Waste wood and the Waste Incineration Directive (WID), page 10.2. England and Wales: EA, Scotland: SEPA, Northern Ireland: NIEA.3. See What is an Air Quality Management Area?, page 11.4. See What is a smoke control area?, page 11.5. See What is the Exempt Appliances list?, page 11. Planning fowchart.
Figure 9
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Under no circumstance can waste wood be burnt iit contains halogenated organic compounds (suchas some timber treatments or chlorine-basedplastics) or heavy metals that ormed part o atreatment or coating such as CCA timber treatmentor lead-based paint, except in a ully licensed, WIDapproved, waste incineration acility. The likely
source o this material would be constructionand demolition waste, or pallets used to conveysubstances containing these materials, e.g. sheepdip. A WID guidance document is available romthe Department or Environment, Food and RuralAairs (Dera), or through the BEC website, settingout what material is exempted rom WID and whatis subject to it (see Sources o urther inormation,page 12).
Dera and the Welsh Assembly Government haveprepared additional guidance to clariy the interacebetween the Clean Air Act and Pollution Prevention
and Control (PPC). This guidance indicates that anyexemptions under the Clean Air Act 1993 or small-scale incinerators or combustion plant burningwaste material do not apply i the activity comesunder PPC regulation. It also indicates that it is notpossible or Dera to consider any new Clean Air Actapplications or exemptions relating to applianceswhich require a PPC permit. Thereore, or example,an application or exemption or an applianceor burning waste wood will only be consideredi the wood waste to be burned will not containhalogenated organic compounds or heavy metalsas a result o treatment with wood preservativesor coating, including, in particular, wood wasteoriginating rom construction and demolition waste.The guidance relating to the interace between theClean Air Act and PPC is listed in Sources o urtherinormation, page 12.
What is an Air Quality Management Area?
Since December 1997 each local authority in theUK has been carrying out a review and assessmento air quality in their area. This involves measuringair pollution and trying to predict how it will change
in the next ew years. The aim o the review is tomake sure that the national air quality objectiveswill be achieved throughout the UK by the relevantdeadlines (see Figure 10). I a local authority fndsany places where the objectives are not likely tobe achieved, it must declare them an Air QualityManagement Area (AQMA); this could be just one ortwo streets or much bigger. Then the local authoritywill put together a Local Air Quality Action Plan toimprove the air quality.
What is a smoke control area?
Under the Clean Air Act 1993 local authoritiesmay declare the whole or part o the district othe authority to be a smoke control area. It is anoence to emit smoke rom a chimney o a building,
Approximate distribution o Air Quality Management Areas at timeo writing. For more detailed maps and up-to-date data seehttp://aqma.dera.gov.uk/maps.php
Figure 10
Local authority hasdeclared an AQMA
Local authority currentlyhas no AQMAs
rom a urnace or rom any fxed boiler i locatedin a designated smoke control area. It is also anoence to acquire a uel other than an authoriseduel or use within a smoke control area unless itis or use in an exempt appliance. The Secretaryo State or Environment, Food and Rural Aairshas powers under the Act to authorise uels orexempt appliances or use in smoke control areasin England. In Scotland and Wales this power restswith Ministers in the devolved administrations orthose countries. Separate legislation, the Clean Air(Northern Ireland) Order 1981, applies in NorthernIreland. Thereore it is a requirement that uelsburnt or obtained or use in smoke control areashave been authorised, or that appliances used inaccordance with their instructions to burn specifedsolid uel in those areas have been exempted by anOrder made and signed by the Secretary o State orMinister in the devolved administrations.
The local authority is responsible or enorcing thelegislation in smoke control areas and they shouldbe contacted or details o any smoke control areasin their area. They should also have details o theuels and appliances which may be used.
What is the Exempt Appliances list?
The Exempt Appliances list shows appliances(ovens, wood burners and stoves) which have beenexempted under the Clean Air Act 1993 or Clean Air(Northern Ireland) Order 1981. These have passedtests to confrm that they are capable o burning an
unauthorised or inherently smoky solid uel withoutemitting smoke when used with certain uels inaccordance with their instructions.
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Sources of further information
TheCarbonTrustpublicationBiomass heating: a practical guide for potential userscan be downloaded rom:www.carbontrust.co.uk/publications/publicationdetail.htm?productid=CTG012
TheguidancerelatingtotheinterfacebetweentheCleanAirActandPPCisat:
www.environment-agency.gov.uk/subjects/waste/1019330/1334884/1721340
HMIP Technical Guidance Note (Dispersion) D1: Guidelines on discharge stack heightsfor polluting emissions is available rom the Environment Agency,Tel: 08708 506 506 www.environmentagency.go.uk
TheWIDguidancedocumentcanbeobtainedfrom:http://archive.dera.gov.uk/environment/policy/permits/documents/ep2010wasteincineration.pd
FordetailsofAirQualityManagementAreassee:
www.airquality.co.uk/archive/laqm/laqm.php
Fordetailsofexemptappliancessee:http://smokecontrol.dera.gov.uk/appliances.php
Biomass heating guides series
This publication should be cited as: Palmer, D., Tubby, I., Hogan, G. andRolls, W. (2011). Biomass heating: a guide to feasibility studies. Biomass EnergyCentre, Forest Research, Farnham.
Other guides in this series:Biomass heating: a guide to small log and wood pellet systemsBiomass heating: a guide to medium scale wood chip and wood pellet systems
Crown copyright 2011
Written, co-ordinated and produced by David Palmer, Ian Tubby, Geo Hogan and Will Rolls,and peer reviewed by members o the Renewable Energy Association.
Inormation on ue design and specifcation kindly supplied by HETAS.
For urther inormation please contact: www.biomassenergycentre.org.ukemail: [email protected]
Editing: Jenny Claridge
Designed and printed by Colourgraphic Arts, Bordon, Hampshire.Published by the Biomass Energy Centre, Farnham, Surrey. www.biomassenergycentre.org.uk
This publication was commissioned by the Department o Energy and Climate Changeand Forestry Commission Scotland or the Regional Biomass Advice Network (RBAN).