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Living Faith for the Earth Churches using biomass technology can reduce their carbon footprint, save money through reduced bills, and through the Renewable Heat Incentive, could earn money

Your Church and Wood Fuel (Biomass) Biomass boilers | Things to consider | DAC criteria This information sheet is produced by the Diocese of Oxford to introduce how biomass could be used to heat your church. It will help you assess the suitability of your church and provides a list of things to consider as you develop a project to install a biomass boiler and benefit from the government Renewable Heat Incentive.

Introduction This leaflet describes how wood fuel can be used to generate heat in your church. It will help you assess the building’s suitability and gives you a list of things to consider as you develop a possible project to install a biomass boiler in your church. By employing this technology, churches can reduce their carbon footprint, save money through reduced bills, and could, by using the government Renewable Heat Incentive (RHI), earn money.

What is Wood Fuel? Burning wood releases heat which can be used to heat buildings and provide hot water. It is the most common form of renewable heating in the UK with a million tonnes of wood being used, mostly on log fires and log burning stoves. However, there are now a range of well proven wood fuel based technologies available to run central heating systems. These are generally referred to as biomass boilers. Biomass has a wide definition, but in heating systems the most commonly used biomass is wood – in the form of logs, pellets or chips.

Is it ok to burn trees? Burning wood does release carbon dioxide (CO2), a greenhouse gas that is contributing to the global warming that we are experiencing. However, the CO2 given out is equal to the amount that was absorbed by the plant when it was growing. So sustainably managed forests take in the CO2, and when we burn the wood the same amount of CO2 is released. It is therefore important that the wood comes from forests where the trees are replanted or naturally regenerate. There are some CO2 emissions associated with the production and transportation of wood fuel, but these are significantly lower than the CO2 emissions as a result of fossil fuels. For example, a church was burning 4,000 litres of oil per year, which produced 12 tonnes of CO2 emissions per annum, with an old and inefficient boiler. Replacing this with a new boiler reduced consumption by 75%, and the biomass boiler that was installed will use 2 tonnes of wood pellets and the estimated CO2 emissions would be around 0.25 tonnes per year. 1. Due to the small use of CO2 within the production process, woodfuel can be referred to as ‘carbon lean’. In the UK, a large proportion of woodlands are under-managed. Yet the flora and fauna associated with our woodlands evolved during times of more active management and need regular access to light. Under managed woodlands have been shown to be getting darker as trees mature and are not thinned out. Therefore by choosing woodfuel, you can help support the sustainable management of woodlands and improve the habitat for the precious flora and fauna of our woodlands.

What issues might there be for my church? 

Space: Biomass boilers generate hot water in the same way as fossil fuel boilers and therefore can be used in the same way, using existing wet based systems within the church building (NB if you currently have electric heating there will be a cost associated with installing wet based radiators) . However, they tend to be larger than their oil or gas equivalents, due to the larger combustion chamber. In addition, wood has a lower energy content per unit volume than fossil fuels, meaning that the volume of wood will be much greater than the equivalent volume of oil. Fuel will need to be stored near the boiler for convenience to minimise handling. This storage area should be dry and have easy access for deliveries.

1Reference: Case Study St Michael and All Angels Church – The First Zero Carbon Church in the UK.


Sustainability: The environmental benefits of using wood fuel are clearly greatest if the wood is sourced from a sustainable local or regional supplier. All woodland that is actively managed in Great Britain will have a felling licence issued by the Forestry Commission. When felling licences are issued the work approved has been checked to ensure it complies with the UK Forestry Standard. The number of woodfuel suppliers are constantly increasing as the market grows. To find your nearest supplier visit or, where contact details and fuel types supplied are provided using simple postcode searches.

Cost: It is worth noting that Biomass Boilers do have a higher capital cost than equivalent fossil fuel boilers. This could be a challenge in terms of raising initial funding. However over the lifetime of a biomass boiler at least 70% of the cost is the fuel supply. Woodfuel is generally cheaper than fossil fuel equivalent – so whilst initial capital cost will be higher, there will be savings in the long term. It is also extremely important that fuel storage and delivery options are considered at the earliest stage of the feasibility work. If an inefficient storage and delivery option is used then this can substantially increase lifetime costs. Early stage discussions can prevent this unnecessary cost.

What types of Wood Fuel are available? 

Chips: Chips come from forest or sawmill arisings or from clean, untreated waste timber. They are more appropriate for larger scale applications, such as community heating schemes. The smallest viable chip boiler is from around 40kW. If road access to the boiler plant is available, and storage is not a problem then wood chip will be the preferred fuel, as it is the most readily available and represents the cheapest cost per kW h generated. Wood chip, at £100 per tonne delivered2, equates to a cost of around 3p/kWh, which is considerably cheaper than gas, oil or other fuels. Using woodchip is the best way of suppporting the local rural economy as it cannot be delivered economically more than 25-30 miles. Larger woodchip systems would work well if supplying the church in association with other properties nearby via a mini-disctrict heating network of two or three neighbouring properties. In this case the church would install a heat exchanger and buy heat from the boiler as required.

Pellets: Pellets are made from wood from sawmill arisings. Pellets are dense and dry, requiring about a third of the storage space of logs or chips. This makes them ideal where storage space is limited. They have a high energy density and uniform shape, which makes them ideal for automated heating systems. Where direct road access is not possible, wood pellets are the most common fuel used, as these can be blown into a fuel silo from up to 30 metres away. These take up only around 25% of the storage space needed for wood chip for the same energy output, but are approximately twice the price, at £190 per tonne delivered, this equates to a cost of 4p/kWh, which is still less than fossil fuel prices.

Fuel quality Good quality fuel is key to the successful and efficient functioning of your boiler. The boiler manufacturer will specify fuel quality required – particularly in terms of moisture content and particle size. It is important not to burn fuel which is wetter than the requirement of the boiler, as this wastes the energy of the wood and can damage the boiler and the flue.,59188&_dad=portal


What boilers are available? Biomass boilers require a conventional chimney flue, which can either be a simple stainless steel flue taken through the roof, or connected into an existing lined brick chimney, as long as it complies with statutory requirements. 

Pellet boilers Have an integral pellet hopper which is often topped up automatically from a larger store next to the boiler. Some boilers have an integrated silo big enough to supply fuel for up to one week. External silos typically hold enough fuel for 2 to 12 months.

Chip boilers Operate in a very similar way to pellet boilers but they do not work effectively below 40kW. This would normally be larger than a church requires, but works well for several buildings.

Biomass boilers are generally less responsive to instant heat demands – they do not modulate as well as fossil fuel boilers. This is because they take longer to heat up, as they are larger, and longer to cool down once they are switched off. Therefore they work best when they have a long constant demand for heat rather than a ‘flashy’ heat demand profile which rises and falls quickly. There are ways that the modulation characteristics can be managed effectively. Firstly pellet boilers are closest in heat response characteristics to fossil fuel boilers. Secondly a buffer tank (a tank of water) can be installed which stores excess heat produced by the boiler working at high demand and the heat produced by the boiler when it is switched off but cooling down. The boiler burns the fuel, and excess heat above the buildings’ immediate heating and hot water needs is used to heat up the buffer tank. The boiler can then be switched off and heat demand met from taking heat from the buffer tank – acting like a heat battery and smoothing the heat demand profile. Installing a buffer tank will however require space. Yet it will increase the overall efficiency of the system. Therefore it is important to consider the heat demand of your church. Some church fabric could benefit from a more regular use of heating. Also it is worth considering what other neighbouring buildings could join you in a heating project – the vicarage? the church hall? the primary school or village hall? Could you consider a larger boiler with a heat pipe linking the buildings together (a small district heating system). This smoothes out the heating demand. Boiler maintenance: Boiler maintenance requirements will be slightly higher than with fossil fuel based systems – for instance including ash removal (ash produced should be no more than 1-2% of the volume of fuel burnt).The boiler installer will carry out an annual service, and will train local users how to use the boiler during the commissioning process. It is important to ensure you have a good relationship with your boiler installation company. For more information on boilers read this leaflet from the Biomass Energy Centre: OR_BIOMASS_2_LR.PDF

What about Hot Water? Any biomass boiler will provide hot water in the same way as a conventional gas boiler. However, there may be more efficient ways of providing hot water in the summer when there is no requirement for the boiler to be on for heating.


Case Study – Case Study St Michael and All Angels Church, Withington. St Michael and all Angels is a Grade I listed building and has installed a 38kW Froling P4 biomass pellet boiler. The church is used for a Sunday service and a mid-week school service. The heating is therefore only required for seven hours per week. A biomass boiler was selected because there was an existing serviceable wet radiator system in the church. Pellets rather than chips were chosen because a pellet boiler can more easily be switched on and off, it is more similar to a gas boiler than using wood chips, plus pellets require less storage space. The boiler is fully automatic, similar to a gas boiler. As the usage was so low, it was feasible to propose a manual loaded system and the pellets are supplied in 10kg bags. Hence, this removed the need for a large hopper to store the pellets. The manual load hoppers store 250kgs and the boiler consumes 60kgs per week, requiring the hopper to be filled every four weeks. The biomass installation replaced an old and inefficient oil boiler. Previous oil usage was 4,000l/year at a cost of around £1,500, carbon emissions were 12.11 tonnes CO2e/year. Replacing this with a new boiler reduced consumption by 75%, and the biomass boiler that was installed uses 2 tonnes of wood pellets, at a cost of £400/year, and the estimated CO2 emissions would be around 0.25 tonnes per year. The biomass installation will therefore save £1,100 per year in fuel costs and just under 12 tonnes in carbon emissions. The cost of the installation was £23,110. Source:

Case Study – St Paul's Church, Gulworthy Cross St Pauls installed a Guntamatic 50kW wood pellet boiler, which in the winter they put on for about five hours before the Sunday service and they also have it for two to three hours twice during the week, depending on the weather. They also have a good number of special occasions such as school services and funerals, but as they are a small community the building is used less often than some larger urban churches. They use approximately five tonnes of fuel per year. The thermostat is set to 20°C, although they don’t achieve that temperature due to the issues of insulating a traditional church building. There was no viable heating before, only geriatric storage heaters. One of their main objectives was to preserve the church fabric by keeping it dry. The total cost around £24,000 not counting radiator installation, the boiler itself cost approximately £18,000. The boiler is housed in a wood shed at the back of the church – planning permission for this was necessary, and was granted on the grounds it was removed if it was no longer needed for the boiler. With the boiler is a canvas hopper which holds up to 4 tonnes of biomass pellets. The full costs were met by grants and donations – split roughly fifty-fifty, most notable was a grant from the Lottery. Although this system has performed extremely well, several difficulties have appeared. The hopper is a synthetic fabric with no way of seeing how much fuel remains and more importantly no provision for topping up between bulk deliveries which are blown in from a large specialist lorry. The fuel is blown down 30m of pipe, which is the limit as to how far fuel can be blown, as access to the church is difficult. This means the pellets are prone to breaking up so baffles have been fitted inside the hopper to prevent pellets hitting the back. Ideally the heat would be on at a low level all week and boosted for services but biomass boilers are not ideal for this, the boilers tending to perform best when at full power. Source: 5

Exploring Wood Fuel for your church IMPORTANT NOTE The most important advice at the outset is that any installation of renewable technologies must be an outcome of a comprehensive project to reduce the carbon footprint of the whole church, rather than as a tariff-generator or indeed as a standalone statement of environmental intent. To help churches get started the Diocese of Oxford has published For Creed and Creation: A simple guide to greening your church. This is a great little book of practical suggestions for making your church more energy efficient. With simple ideas and advice from the way the building is run, to how rubbish is recycled and the light switches used, the guide will help to reduce bills and put your church on the right track to tackling your carbon footprint in simple and cheap ways. To read the For Creed and Creation book, and to order copies, visit:

Things to do 1. Be encouraged - Caring for the environment is a crucial part of mission and the Living Faith vision. The church has a unique role to play in environmental issues, which in turn provide opportunities to model, in practical ways, the love of God. Furthermore, biomass boilers can mean that the building is warm all week, giving greater opportunities for the community to ‘cross the threshold’ and use the building for community events. 2. Carry out an environmental assessment and energy audit – Using the book For Creed and Creation, the Suggested List of Eco-Professionals (see resources at end), and environmental enthusiasts from your church and local community carry out an environmental assessment and/or energy audit of your church building and activities. Would biomass boilers fit within a comprehensive effort to reduce the carbon footprint of the whole church? You must deal with the basics before considering biomass boilers – insulate the walls, the roof and the windows, where possible. 3. Contact the DAC – Biomass boilers in churches will probably require some redesign as they are larger than conventional heating systems. It is best to involve the DAC from an early stage to ensure you have the best advice. (See DAC guidelines and contact details on pages 9 and 10) 4. Follow the example of others - There are other churches who have installed biomass boilers. Visit them to see what was involved, ask for copies of relevant documents, take photographs and feed-back to your PCC. Ask the PCC for permission to do a feasibility study for your church. 5. Community involvement - Winning the hearts and minds of your Community and stirring enthusiasm will help make your project run more smoothly and increase your funding opportunities. Meet and talk to as many people as you can – the local school, community groups (such as parents and toddlers), local environmental groups, the Parish Council, your PCC, your whole congregation. Help others see that becoming more ‘green’ is possible, desirable and relevant to the life and mission of your church. It may be that several community buildings could be heated by a single boiler. 6. Feasibility study – Some groups, such as Better Planet (who design, supply and install renewable technologies) and the Forestry Commission (who are committed to maintaining sustainable forests) , offer free advice on using woodfuel and it is worth getting as much information as possible about what different solutions will work for your building. One of the first considerations will be whether to heat your 6

church using a biomass boiler or whether heat pumps are more appropriate. Biomass boilers are a cheaper option, but the storage of fuel may be an unassailable problems. Installers will give you preliminary quotes based on the volume of space and the heat losses in the building (see Installers and Professionals section overleaf). The DAC have a specialist advisor for heating who can be made available by contacting the DAC Secretary. Also start looking at ways of funding the project (see Funding section below). Be aware that if you wish to apply for support through the Renewable Heat Incentive you will need to ensure that you have not had any public funding for the installation. This includes funding from central or devolved government schemes, local authorities and European schemes which contribute to the direct costs of the renewable heat installation or its operation. For an excellent guide to doing a feasibility study read “Biomass Boilers – a guide to feasibility studies” 5_FOR_BIOMASS_3_LR.PDF 7. Put together a proposal - If the PCC is happy with the feasibility study findings then set up a group to prepare a proposal. This will be useful for obtaining funding and for the Faculty. Involve your Church Architect, the treasurer and the DAC. Look at proposals from other successful churches. Remember that you are more likely to be successful in gaining funding if you can show that there is communitywide involvement in your project. 8. Work with English Heritage, SPAB and the District Council - If your building is listed then you will need to work alongside English Heritage and SPAB (Society for the Protection of Ancient Buildings). This will involve a number of visits to prove that the biomass boiler will not harm the building. A Faculty from the DAC will probably take about 4-6 months to achieve. If you need to add an additional shed for storage then this may require planning permission which is given by the District Council (your Church Architect should be able to help with this). 9. Contact Ofgem- The Gas and Electricity Market Authority (Ofgem), will be responsible for administering the Renewable Heat Incentive (RHI). They will deal with applications for support, the accreditation process, making incentive payments to participants and ensuring compliance with the rules and conditions of the scheme. 10. Installation - Having received your Faculty, approvals and planning permission, gained your funding and become confident you are eligible for receipt of the Renewable-Heat-Incentive, you are in a position to install your biomass boiler. Inform your insurers about the installation. It shouldn’t raise your insurance premium. 11. Celebrate - Throw a Church warming party, thank the community for their help, tell your local media, hold a special service of thanksgiving with some guests.

Funding Churches that have successfully installed Biomass Boilers have so far managed to access grants and raise the remaining funds locally. Some banks may lend you the money. Start exploring funding options at the same time as starting the process of gaining a Faculty. 

Grants – There are many grant making foundations that will consider this sort of project, for example you may be able to apply to the Landfill Communities Fund ( Look for local foundations and use the contacts of your congregation. You may also contact the Environment Officer ( for the latest suggestions.

Local fundraising – Many people are happy to contribute to projects of this nature, especially if it is part of a reordering project that improves the wider community use of the building. They will also like the fact that the project will provide a long-term income for the church through the Renewable Heat Incentive (RHI).


What is the Renewable Heat Incentive? The Renewable Heat Incentive (RHI) is designed to provide financial support to encourage individuals, communities and businesses to switch from using fossil fuel for heating, to renewables such as wood fuel or heat pumps. Anyone who has installed eligible technology since 15th July 2009 will be able to apply for the RHIs. The scheme will be introduced in two phases. 

The first phase, will be targeted in the non-domestic sectors, which should include churches, and opens for applications from the end of November 2011. Under this phase there will also be support of around £15 million for households through the Renewable Heat Premium Payment, which churches cannot access.

The second phase of the RHI scheme will see it expanded to include more technologies as well as support for households. This transition will be timed to align with the Green Deal, which is intended to be introduced in October 2012.

The incentives will apply for biomass boilers (The Tier Break is installed capacity x 1,314 peak load hours, i.e. kWth x 1,314):   

Small biomass, Less than 200kWth - Tier 1: 7.9p/kWh, Tier 2: 2p/kWh Medium biomass, 200 - 1,000 kWth - Tier 1: 4.9p/kWh, Tier 2: 2p/kWh Large biomass, 1,000 kWth and above – 2.7p/kWh (see ofgem’s Simple Guide:

So, if a small church installs a 38kWth biomass boiler and uses it for seven hours per week, then the money given by the government will be: 38 times 7 to calculate the kWh per week = 266kWh multiplied by 52 to get the annual usage = 13832kWh per annum times 7.6 pence (divide by 100 to get pounds) = £1051.23 per year, rising with inflation – linked to the Retail Price Index. Other sources for information and guidance on the RHI include: 

Energy Saving Trust:

Department for Energy & Climate Change:

Forestry Commission:

Better Planet:

Installers and professionals All biomass boilers of 45kWth capacity or less will need both the technology and the installer to be certified under the Microgeneration Certification Scheme (MCS) (, in order to qualify for the Renewable Heat Incentive. The Diocese of Oxford has put together a suggested list of eco-professionals that have had experience of working in churches and that offer a range of services, such as energy efficiency audits and renewable energy installations. This is not necessarily a recommended list, but rather a starting place for those wanting to find companies with experience of working in renewable advice and installations with churches. To see the current list of eco-professionals visit: 8

DAC Guidelines: Biomass boilers in church buildings The Diocese Advisory Committee (DAC) guidelines for the installation of biomass boilers, are as follows: The DAC regards the use of a biomass boiler to be a very sensible option where your current boiler is in need of replacement, and you have the space for the equipment – for example a large boiler house which may indeed have housed a Victorian ancestor of this technology. When investigating an installation of this sort, parishes are asked to consider the following questions: • •

What space do you have for the plant, and what is your budget? Where will the fuel be sourced from, and what form would it be in? The fuels from local sources have the smallest carbon footprint, but may not be processed into chips and, therefore, burn less efficiently (as well as require more storage space). Do you have helpers available? Some boilers automatically refill by a gravity feed from the fuel store via a large bore pipe, but these are expensive and require greater disruption to install. Boilers with smaller hoppers are easier to install and require less space, but will need to be topped up manually, depending on how often the boiler is used. Is biomass compatible with your existing heating system (i.e. a wet radiator system), or do you have to install a new system in any event because of failure or poor efficiency? If you are installing a new system, heaters and pipework will need to be carefully and discreetly sited under the direction of the DAC.

In addition, the DAC would ask for the following when formally considering an application: Preparation 1) Parishes should provide the DAC with statements of need and significance. The desire to get the Renewable Heat Incentive alone does not constitute a need. 2) Parishes should also include in their application details of where fuel is to be sourced from, the estimated annual fuel requirement, and how the system is to be used (for example, is the building to be heated constantly at low level, or will the system only be fired up for services?). 3) Parishes should prove to the DAC that the proposed installation is part of a wider package of measures they have already taken or are taking towards better environmental stewardship. Ideally parishes should be following the eco-congregation or Shrinking the Footprint path. 4) There should be a current and competent energy audit of the building. 5) Contractors should provide a feasibility document identifying the expected efficiency of the installation (%), heating outputs, monetary and carbon payback periods. 6) The comment of the inspecting architect is essential, and wherever possible he/she should be closely involved in the proposals. Consultation 1) Parishes should consult with the appropriate bodies, dependent on the grade of the building and the significance of the space to be used for the plant, including English Heritage, SPAB, Victorian Society, and the local planning authority (especially the latter where new external structures are required as planning permission may apply). 2) A letter of consent from the insurers is essential. 3) Comment from the diocesan heating adviser is essential – this can be obtained through the DAC office. Post-installation 1) After the first twelve months an evaluation report is to be produced outlining how successful the system has been, any problems experienced, the amount of fuel used compared to hours of use, and earnings under the Renewable Heat Incentive. This should be sent to the DAC and copied to the diocesan environmental adviser (see contact details overleaf). 2) The installation should be inspected annually by a suitably qualified heating engineer. 9

Further Resources Environment related news and further information on the Diocese of Oxford and the environment can be found at Church building resources: 

DAC - Diocese of Oxford:

Shrinking the Footprint website:

Church Care website:

Eco-Congregation website:

Biomass Boiler resources: 

Biomass Energy Centre: – including A guide to medium scale wood chip and wood pellet systems ( 37821_FOR_BIOMASS_2_LR.PDF) and A guide to feasibility studies ( 38215_FOR_BIOMASS_3_LR.PDF)

Woodheat Solutions:

Renewable-Heat-Incentive resources: 

Ofgem: - including A Simple Guide which can be downloaded at

Energy Saving Trust:

Department for Energy & Climate Change:

Better Planet:

Forestry Commission:

Diocese of Oxford Contacts DAC Secretary: Natalie Merry | | 01865 208229 Environment Officer: Matt Freer | | 01865 208745

Earthing Faith Earthing Faith is a network established by the Diocese of Oxford to resource and encourage individuals and churches in the diocese as they connect their faith with the earth. To join the network or to find out more, visit: Acknowledgements: This guide was written and edited by Lesley Fellows (Renewable Technology Advisor) and Matt Freer (Environment Officer), with input from Natalie Merry (DAC Secretary) Photo credits: Flickr user: akahodag (pg 2); © Crown Copyright, FC Picture Library / Isobel Cameron (pg 3 top) & John McFarlane (pg 3 bottom);

Updated June 2012

Woodheat Solutions – KWB, Austria (pg 4) Jane Hull (pg 5 top); Centre for Sustainable Energy/ (pg 5 bottom)

Post: Environment Officer, Diocese of Oxford, North Hinksey, Oxford OX2 0NB Tel: 01865 208745 | Email: Web: | 10

Your church and Woodfuel (Biomass) Info Sheet  

This information sheet is produced by the Diocese of Oxford to introduce how biomass could be used to heat your church. It will help you ass...

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