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How to carry out a successful biomass heating project

Biomass produces low carbon heat at a lower than conventional forms of heating, meaning it’s a good way to reduce your organisation’s energy costs and carbon footprint, and protect against fluctuations in fossil fuel costs.

About this guide

With a host of technologies and fuel supply options to choose from, finding the biomass solution that will work best for you can seem daunting.

This guide will help to give you clear step-by-step guidance and all the information you need to have informed conversations with potential suppliers and procure a biomass system that best fits your organisation’s needs.

Understand your requirements

The first step is to decide what you need a biomass boiler to do for you. Different organisations use heat in different ways – such as heating premises, providing hot water or for process heating.

It is important to consider your current heat requirements and how these might change in the future, based on your business plans. This will affect your choice of system, how much fuel you use, and the amount of income you may get from the Renewable Heat Incentive (RHI).

A complete understanding of how you use heat allows a supplier to design a system that meets your needs and operates efficiently and reliably.

Check your use of heat

To get a clear picture of how much heat you use, you can look at records of your existing fuel consumption, ideally covering at least one full year. If there have been any changes to your site or operations during that time, these should be noted.

Your energy consumption will be stated on your bills for electricity or mains gas. If you use oil or liquefied petroleum gas (LPG), your delivery notes should state the volume delivered.

If you have half-hourly data relating to your electricity and gas use, then these can be used to determine the total amount of heat, the peak heat load and the way your use of heat varies throughout the day. This can be very valuable in accurately matching a biomass system to your needs.

You also need to know the maximum rate at which you will use heat. This is referred to as the peak heat load and is measured in kWth. Your existing boiler will most likely have a rating plate that states the maximum rate at which it can supply heat. It is unlikely that this will be exactly the same as your existing peak heat load – boilers are often selected to have a greater heat output than the peak heat load of the system they serve.

It is important that you are aware of any unusual requirements that your property has. This calculation can often be done by a supplier providing a detailed quotation, but you may need a heating design engineer to specify this for you. Such an engineer may be listed by the Chartered Institution of Building Services Engineers (CIBSE).

Common practice

It is common practice to install a biomass boiler with a maximum heat output that is lower than peak requirements and have a back-up heat source (such as a gas boiler) to provide top-up heat during times of maximum load.

Installing an oversized biomass boiler will result in poor fuel efficiency, reliability problems, and high running costs. Biomass boilers can take hours to heat up from cold or to cool down, so most systems are used in conjunction with a thermal store or buffer tank.

This contains a large volume of water and can maximise the efficiency of the system or make the system more convenient to use. A buffer tank absorbs excess heat from the boiler and releases this during periods of peak demand. A thermal store can be heated over a period of hours by a relatively small boiler to supply large peak demand.

Is my site suitable for biomass?

It is important to check whether it is possible to have a biomass system at your site and identify any restrictions on the technologies that you could select. The key questions you should consider are:

Is your site in an air quality management area?

These areas are where emissions are very strictly regulated. For biomass boilers, this often means additional flue-gas abatement measures, which can be costly. More information can be found on the Air Quality in Scotland website.


What space do you have?

Biomass systems can take up significantly more space than oil or gas boilers, especially once fuel storage and buffer tanks are considered. A 200kWth biomass system would typically have a footprint of around 3m x 9m (including fuel store). It is important to make sure you have enough space for the type of system you are considering.


Is there access to the site for deliveries of fuel and equipment?

It is important to make sure your site has suitable access for fuel delivery vehicles. Most fuel suppliers would be willing to visit your site to confirm that the access is sufficient for their vehicles. It is important you make yourself aware of width, height and weight restrictions that may limit access to your site.


Are there planning restrictions?

It is likely that planning permission will be required for parts of the system. There may be some visual intrusion from the flue stack, biomass plant room or fuel store. Flue gas emissions will also need to meet the requirements of the local environmental health officer (EHO).

Find a supplier

The next step is to find a supplier to install your biomass system. If you know someone who has recently undertaken a biomass heating project, ask if they would recommend the supplier they used. You can also use the Green Network for Businesses to find out about other organisations that have switched to biomass, learn about these projects and arrange to visit an organisation near you to see and discuss what they did first hand.

Renewable energy systems that generate heat and have an output of less than 45 kilowatts thermal (kWth) are covered by the Microgeneration Certification Scheme (MCS). The MCS regulates many aspects of suppliers’ dealings with their customers – including initial quotes, system design, installation and end-user documentation. If you’re considering a system with an output of more than 45kWth, you’ll have more options in terms of boiler type and fuel, but it’s likely that more than one supplier will be involved.

Have initial discussions with suppliers

By now, you should have a good idea of what you want from the biomass system:

  • How easy is this to operate?
  • Savings made?
  • How much money do you have to spend?
  • How much heat you need?
  • How do you use this?
  • What space you have available?
  • What fuels you can source?

The next step is to discuss your options with a number of suppliers. This will help you narrow down your options and decide which systems are the most appropriate for your site. Many suppliers will provide an estimate of costs and an outline proposal free of charge. They will want to visit your site to understand your situation and identify any significant issues.

Decide what you want

Once you have proposals from a number of suppliers you should review these and narrow down your options, so you can get detailed quotes for your preferred system. It is particularly important to compare fuel and fuel handling equipment as this impacts the costs and financial returns of a system.

You should review and compare each proposal and consider the following:

  • The capital cost of buying and installing the system, including any enabling works  such as planning approval or building works, which may not be included in the supplier’s costs
  • Operating costs including; maintenance, repair, any additional labour to operate the system and the operating cost of any additional plant required and fuel
  • Income from the RHI

A number of companies offer contracts to maintain the boiler and supply fuel in return for a fee. This is usually payable per unit of heat delivered rather than a flat fee. This arrangement ensures that it is in the supplier’s interest for the system to be operating as much of the time as possible.

Get quotes

By now, you should have a clear idea of the type of system you are going to purchase and be ready to request detailed quotations. For larger or more complex systems, it is important that you prepare a specification. This is usually done by a design engineer with experience of biomass systems. For smaller systems, it may be appropriate for your supplier to complete the design. In this case, it is important to state clearly what you need the system to do for you when it is operating and what they should consider during installation. Below are the types of information you should share.

  • The time window for the work to be done and any limits on operating hours. You may wish to consider including penalty clauses in your contract so that you can recover any costs to your organisation from works overrunning
  • Site-specific requirements, such as running checks with Disclosure Scotland, ATEX 1 restrictions or site rules that may have an impact on the way suppliers work
  • Any specific health and safety issues that could affect the project cost or length
  • Heat requirements
  • Operational requirements

Review your quotes

As ever, one of the most important aspects of any quotation is the price. However, when you are buying a biomass system you need to find out how the various systems compare to your actual needs. Check each quote to ensure suppliers have quoted what you asked for.

You should also check the following:

  • Exclusions
  • Assumptions
  • System design
  • Guarantees
  • After-sales support and servicing
  • References

Finalise your business case and get approval

Once you have accurate costs from suppliers, you can produce your business case, which will be used to gain approval for internal and external funding.

If you need to access finance, check out our free guide. This will show you how to prepare a robust business case to support your proposed investment decision and how to present a strong case for investment to your senior management or external lenders.

When developing your business case, confirm any assumptions made at an earlier stage, such as fuel costs or additional labour required. Sites with similar systems can be very valuable sources of information that is otherwise difficult to get – in particular, any additional labour required.

If your system is over 200kW, you can seek preliminary approval for the RHI. This will provide some assurance that the RHI application will be granted, as long as the system is installed as described and meets any conditions applied by Ofgem.

Get planning permission and order your system

Apply for planning permission before ordering the system, as soon as your design has been finalised. By contacting your local planning department staff at an early stage in your project, you should have a good idea of what information is needed to support the application. You may only need permissions for a new flue, or this may be needed for the construction of a new plant room, fuel store and flue.

Once you have the permissions you need, you can go ahead and order your system.

As with any project, creating an accurate project plan is key to success. With a biomass system, it is important to consider and mitigate any disruption to your organisation. You may need to turn off the heat and prevent access to parts of your site, and there may be additional noise or dust. This is also the time to finalise any other agreements such as organising the fuel supply and maintenance.

Further support

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