Air quality and biomass installations. A briefing for local authorities

Transcription

1 Air quality and biomass installations A briefing for local authorities March 2011

2 Published by BioRegional Development Group BedZED Centre, 24 Helios Road, Wallington, Surrey SM6 7BZ. We are grateful for the assistance of Environmental Protection UK in the production of this report. This report is funded by the Forestry Commission (assisted by funding from the EU Interreg IVB Programme for North West Europe)

3 Air quality and biomass installations Biomass boilers will form a part of the future energy mix in urban areas, including Greater London. However, the demand for sustainable energy and the need to maintain and/or improve air quality in the same areas needs to be balanced to ensure London becomes a truly sustainable city in the future. This document is designed to assist local authority officers, specifying or reviewing biomass boiler proposals in London Boroughs, with understanding the process of assessing the impact of individual or multiple boilers on air quality. Section 1 provides the technical and policy context to biomass installations and air quality concerns, and will be relevant to several departments within your local authority. Section 2 explains what is required to comply with the latest air quality legislation and how biomass installations should be assessed in relation to air quality. This guidance is for biomass boiler installations <20MW, regulated by the Clean Air Act. Larger plant, and smaller plant that burn waste wood, are regulated under the Pollution Prevention and Control (PPC) regime and is outside the remit of this document. Part 1: Context What we mean by biomass Biomass is biological material derived from living, or recently living organisms. In the context of biomass for energy, this is often used to mean plant based material. Within this definition, biomass for energy can include a wide range of materials: virgin wood, energy crops, agricultural residues, food and industrial waste and coproducts. In this document, virgin wood is being referred to when the term biomass is used. This is wood that has had no chemical treatments or finishes applied. Virgin wood comes from a variety of different sources, for example, residues from tree surgery, woodland management and co-product from sawmills. Whilst sawmill co-product may be termed as waste wood (since it is a by-product of another process), there is an important distinction between virgin waste wood such as this, and other waste wood, for example, waste wood from construction which has been chemically treated in some way. The role of biomass in London Biomass conversion technologies are a source of renewable and low carbon energy and are an important part of the energy mix, helping the UK to: mitigate climate change, ensure the UK s energy security, and become more sustainable. There are national and international policies in place driving these efforts: The Climate Change Act 2008: setting reduction targets for CO2 emissions EU Renewable Energy Directive (2009): quantifying a requirement for the use of renewable energy The London Plan and the Mayor s Energy Strategy: as part of addressing local climate change and renewable energy strategies, renewable energy targets for new development and regeneration projects are required across all Boroughs. 3

4 Landfill tax: sending one tonne of biomass to landfill costs 48 + VAT because it is classed as active waste. The Government announced in the Budget 2010 that the rate for active waste will continue to escalate by 8 per year until at least 2014/15, when it will reach 80 per tonne. Why is air quality an issue? Human exposure to air pollution is associated with several serious heart and lung illnesses and premature death. In addition, existing health conditions, such as asthma, can be exacerbated by air pollution. The European Union has identified twelve air-borne pollutants which can be damaging to human health, and has set targets for their concentrations in outdoor air. The following are associated with biomass combustion; nitrogen dioxide (NO 2 ), particulate matter (PMs) and sulphur dioxide (SO 2 ). In comparison to fossil fuel systems, biomass boilers typically produce greater amounts of these emissions than gas boilers but less than coal and oil boilers. Regulation of air quality The Clean Air Act 1993 is the primary regulatory legislation for smaller biomass burning plant. Local authorities are the regulating body for the conditions of the Act. The most commonly known parts of the Act are those that allow local authorities to set up Smoke Control Areas, where domestic premises burning solid fuel are committing an offence unless they use an approved smokeless fuel, or an exempt (approved) appliance. The Act also contains powers regarding the control of emissions from larger biomass boilers. The Environment Act (1995) established the Local Air Quality Management (LAQM) framework for local authorities. LAQM requires individual local authorities to periodically assess air quality, and identify locations where the national air quality objectives for seven key pollutants may not be met by their target dates. Where any such exceedances are predicted, and where there is relevant public exposure, local authorities have a duty to declare Air Quality Management Areas (AQMAs) following a process of consultation. Such designations are a statutory requirement, with local authorities in all parts of the UK having a duty to work towards achieving the national air quality objectives. Following the designation of AQMAs, local authorities are required to develop Air Quality Action Plans (AQAPs) to identify and implement actions to improve air quality locally. Such plans require effective collaboration between local authority departments, external agencies and stakeholders (such as environmental regulators, the Highways Agency and industry). Land-use planning (and transport planning) also underpin the development of effective air quality action plans, and close liaison between air quality and planning officers is therefore critical to improving air quality. In land-use planning air quality can be a material consideration, and is therefore a factor in planning applications that potentially adversely affect air quality, or those that may introduce new exposure to poor air quality (e.g. new housing, offices or shops in area of poor air quality). The Mayor s Air Quality Strategy The Mayor s Air Quality Strategy aims to ensure that Greater London reaches the targets set out in the Government s Air Quality Strategy (in line with the EU Air Quality Directive) and that local authorities meet their LAQM targets. In order to do this, the strategy (policy 8) proposes the following in relation to biomass installations: emissions limits for PMs and nitrogen oxides (NOx) will apply for new biomass boiler installations an emissions assessment will be required as part of the standard air quality assessment submitted with planning applications for new developments including a biomass boiler biomass operators will be required to provide an annual maintenance report to demonstrate continued appliance with emission limits. Biomass boilers and air quality Biomass boilers typically produce more pollutants than gas equivalents but less than oil or coal-fuelled systems. The quantity and mix of emissions depends on the design of the boiler and the specification of fuel. Recent research 1 indicates that the size of woodfuel (e.g. pellets or wood chip) has no bearing on emissions, rather it is the efficiency of the combustion process in the boiler, which is influenced by moisture content of the woodfuel. To understand the potential impacts on air quality a detailed assessment of the biomass boiler system should be undertaken. This is important because it is the combination of a number of factors that creates efficient combustion and therefore lower emissions. 4 (1) Measurement and Modelling of Fine Particulate Emissions (PM 10 & PM 2.5 ) from Wood-Burning Biomass Boilers, Report to the Scottish Government, AEA, January 2008

5 System design The following factors should be considered when specifying or reviewing biomass installations: Biomass boiler The amount and type of emissions produced depends on the type of boiler used and the efficiency of the combustion process. Further to this, the make, model, thermal capacity (kw,mw), seasonal efficiency, maximum rate of fuel consumption (kg/ hr or m3/hr), the combustion and fuel feed systems, emissions abatement equipment fitted and whether the system is fitted with an accumulation or buffer tank, should all be ascertained. Knowledge of these components can be obtained from the manufacturer or the installer and allows an initial emissions estimate to be calculated. System sizing and load matching The operational profile of the heating load needs to be carefully assessed to ensure that the boiler specified matches the proposed use. For example, biomass boilers will produce more emissions when operating significantly below their rated capacity (less than 30% of full load), common with oversized systems. Therefore, systems must be correctly sized for expected heat loads. Similarly, biomass boilers produce more emissions during start-up/shut-down and it is therefore preferable to keep them running continuously rather than switching them on and off to meet variable heat loads (short-cycling). One way to ensure the boiler operates efficiently is to size it correctly based on a sound understanding of the daily and annual heat demand profiles of the site. The use of accumulator or buffer tanks can also help a system run continuously when there is a variable heat load. By assuring compatibility between the fuel type and boiler, the potential emissions will be lowered. Standardisation will help the matching of fuel type to biomass heating systems. The European Committee for Standardisation has developed standards allowing all relevant properties of biomass fuel to be described (CEN/TC 335). These can be downloaded from the Biomass Energy Centre 3. Prior to these Europeanwide standards being developed, individual countries developed their own standards. Boiler manufacturers still sometimes specify fuel according to these, for example, Austria s Onorm standard. A fuel supply agreement should be presented with any biomass boiler proposal to demonstrate that the correct type and quality of woodfuel is available for delivery in the locality. Flue (boiler stack) Once the emissions of the boiler have been estimated, it is then important to consider the design of the flue, since this will have a strong influence on the dispersion of the pollutants throughout the surrounding area. Maintenance Efficiency and emissions performance of a biomass boiler also depend on regular maintenance. Each plan for a biomass boiler should include a regular maintenance schedule to ensure that the boiler remains clean, any faults are fixed and it is de-ashed. Poor maintenance will lead to reduced efficiency of combustion and an increase in emissions. Fuel Biomass boilers are designed to work best with specific fuel types, defined by a series of characteristics: physical (including particle size, bulk density and energy density) biological (including presence of any allergens and carcinogens) chemical and combustion (including chemical make-up and ash content). (3) Biomass Energy Centre 5

6 Part 2: Assessing potential impact on air quality from biomass boilers This section explains the process a proposed biomass boiler installation should go through in order to assess its potential impact on air quality. This information will be useful to local planning authority officers reviewing applications as well as officers specifying biomass boilers. Do all boilers need an air quality assessment? Planning permission will be needed for biomass boilers included in new build and major refurbishment projects. However, in cases where a biomass boiler is planned for an existing building, planning permission may not be required if the flue stack protrudes less than one metre above the building (new boiler house, external fuel store and flue with building clearance of over 1m may need planning permission). All boiler installations should be discussed with the local planning authority to clarify whether or not planning permission is required; the LPA should also keep records of all biomass boiler proposals/installations in the area for the purposes of understanding cumulative air quality impacts. If a biomass boiler does not require planning permission, it should still be checked for compliance under the Clean Air Act as the whole of London is covered by Smoke Control Areas. The assessment process The Mayors Air Quality Strategy requires four tasks to be completed for biomass boiler included in planning applications: Task 1: Assessment of boiler emissions. Task 2: Provide evidence that: - boiler emissions assessment has been included in the site air quality assessment (where biomass boiler is part of new development) - suitable mitigation measures have been included (if required). Task 3: Provide evidence that proposed biomass plant does not exceed NOx and PM limits set by the Mayor for London (limits to be set). Task 4: Site operator to submit annual evidence of continued compliance with NOx and PM limits in the form of operation and maintenance plan. The granting of planning permission will be reliant on all of the above steps being completed. However, the decision as to whether the biomass boiler poses a significant risk to air quality, and therefore whether or not it can be granted planning permission, will be made by the local planning authority, based on the assessment undertaken in task 1. Table 1, outlines the steps the local planning authority should follow to assess the boiler s compliance under task 1 above. The Mayor is also planning to develop a checklist to guide boroughs and developers in the assessment of the potential emissions from new developments, including biomass boilers. Tasks 2-4 involve the local planning authority collating information submitted for the boiler and reviewing it to ensure requirements are met. Cumulative impact Individual biomass boiler applications will most likely be dealt with on a case by case basis however it may also be advisable to consider the cumulative impacts of boilers across the borough. Although there is no mandatory requirement to do so within the Mayor s Air Quality Strategy there are several references to authorities using the planning system to deal with the cumulative effects of developments on air quality. The following steps will enable you to assess the cumulative impact in your local authority: Keep a record of biomass boiler applications and installations (make this known to all LA departments) Use cumulative impact screening tool to flag up any problems Share records with neighbouring local authorities so assessments can include installations near boundaries Monitor single domestic biomass installations (where possible) using standard record sheet EPUK has developed template documents for the above which can be found at: 6

7 Table 1 Steps involved in assessing boiler emissions Relevant reference documents Step 1. Collate basic information on proposed boiler Collate basic details about the boiler, including location, fuel substitution, emissions performance, woodfuel type. Section Biomass and air quality for developers (EPUK & Local Government Regulation, previously LACCORS, 2009) Step 2. Initial assessment Using basic boiler details, appraise boiler against checklist of questions relating to SCAs, AQMAs, boiler exemption and material considerations If the initial assessment reveals no risk to air quality, check the boiler is compliant under the Clean Air Act and proceed with other tasks required by Mayor s Air Quality Strategy. If the initial assessment suggests the biomass installation could pose a risk to air quality, screening will need to be undertaken by the local planning authority; proceed to step 3. Section 4, para Biomass and air quality for developers (EPUK & Local Government Regulation, previously LACORS, 2009) Step 3. Screening Follow Defra s LAQM Technical Guidance to undertake a Screening process. Further, detailed information on the proposed biomass boiler should be collated using a standard template. The Screening process will inform whether the proposed boiler poses a significant risk of an exceedence of an objective to justify a detailed assessment. If the initial assessment reveals no risk to air quality, check the boiler is compliant under the Clean Air Act and proceed with other tasks required by Mayor s Air Quality Strategy. If screening suggests that the risk to air quality posed by the biomass boiler is significant, move on to step 4. Biomass boiler information request template for local authorities (EPUK and Local Government Regulation, previously LACORS 2009) Chapter 5, Section D, Box 5.8 Screening Checklist, Biomass Combustion - LAQM Technical Guidance (Defra 2009) LAQM support website Details of screening tools, Appendix C Biomass and air quality for developers (EPUK & Local Government Regulation, previously LACORS, 2009) Development Control: Planning for Air Quality (EPUK 2010) Step 4. Detailed assessment - Dispersion modelling Request project owner of biomass boiler proposal commissions dispersion modelling assessment. This will be used to ascertain whether the boiler poses a risk to air quality and to calculate the stack height needed to ensure that emissions are sufficiently dispersed. Final decision on acceptability of the boiler s impact on air quality should be made by an air quality expert, following a standard assessment of signficance. If dispersion modelling suggests that the risk to air quality posed by the biomass boiler is significant, move on to step 4, identifying mitigation measures. From Section4, Para 4.23, Dispersion modelling and stack height assessment - Biomass and Air Quality for Developers (EPUK & Local Government Regulation, previously LACORS, 2009) Chapter 6, para 6.56 Detailed assessments, Biomass Boilers - LAQM Technical Guidance (Defra 2009) Chapter 6, from para 6.4 Assessment of significance by the planning authority - Development Control: Planning for Air Quality (EPUK 2010) LAQM support website Step 5. Mitigation measures Support project owner of biomass boiler proposal in identifying mitigation measures to reduce air quality impact. Repeat steps 3-4 taking into consideration selected mitigation measures. If mitigation measures fail to reduce risk adequately, the biomass boiler application should be rejected. If mitigation measures result in acceptable levels of emissions, the boiler application should be granted permission and mitigation measures detailed within a planning condition. From Section4, from Para 4.32Mitigating impacts - Biomass and Air Quality for Developers (EPUK & Local Government Regulation, previously LACORS, 2009) Chapter 6, Mitigating Impacts - Development Control: Planning for Air Quality (EPUK 2010) LAQM support website 7

8 Reference documents AEA Energy & Environment for Scottish Government (2008) Measurement and Modelling of Fine Particulate Emissions (PM 10 & PM 2.5) from Wood-Burning Biomass Boilers [Online]. Available: [01 March 2011] Biomass Energy Centre website CEN & BSI ( ) Published Biomass Technical Standards [Online]. Available: biomassenergycentre.org.uk/portal/page?_pageid=77,19836&_dad=portal&_schema=portal [01 March 2011] Defra (2009) Local Air Quality Management, Technical Guidance LAQM.TG(09) [Online]. Available: [01 March 2011] Defra Air Quality Management Areas (AQMAs) website - EPUK (2010) Air Quality and Climate Change: Integrating Policy within Local Authorities [Online]. Available: [ ] EPUK (2010) Development Control: Planning for Air Quality [Online]. Available: [01 March 2011] EPUK & Local Government Regulation, previously LACORS (2009) Biomass and air quality for developers [Online]. Available: [01 March 2011] EPUK (2010) Development Control: Planning for Air Quality [Online]. Available: [01 March 2011] EPUK & Local Government Regulation, previously LACORS (2009) Biomass and air quality for developers [Online]. Available: and_air_quality_guidance.pdf [01 March 2011] EPUK & Local Government Regulation, previously LACORS (2009) Biomass Boiler Information Request Template for Local Authorities [Online]. Available: [01 March 2011] EPUK & Local Government Regulation, previously LACORS (2009) Biomass Boiler Inventory Template [Online]. Available: [01 March 2011] GLA (2010) Clearing the Air, The Mayor s Air Quality Strategy [Online]. Available: [01 March 2011] LAQM support website - Smoke Control Areas website - Published by BioRegional Development Group, BedZED Centre, 24 Helios Road, Wallington, Surrey SM6 7BZ. Registered charity no