How Do Wood Pellet Systems Work in the UK?

How Do Wood Pellet Systems Work in the UK?

The UK has lagged behind some of its European neighbours, such as Austria, Sweden and Germany, in terms of its use and practical knowledge of biomass boilers.  Users of wood pellet boilers in the UK have sometimes run into difficulties due to several issues:

–          the original installers may not have been sufficiently trained to install the boiler correctly (its buffers and controls are very different to our usual domestic systems); and correct siting of the flue is essential

–          the customers may not have been sufficiently instructed by the installers about how to maintain the boiler (such as cleaning the flue and annual boiler service)

–          difficulty in ordering replacement parts speedily where the boiler was manufactured abroad

–          the availability of a local wood pellet supplier (with pellets guaranteed from a sustainable source) consistency of supply and delivery format (i.e. the choice of loose pellets or 10kg packs, according to the type of boiler/hopper/store)

–          potential customers of wood pellet boilers have been put off by the up-front cost of the boiler/installation.

Through the Renewable Heat Incentive (the RHI) introduced in April 2014, the Government has now raised the bar in helping the UK to not only tap into more of its biomass resources for renewable energy but has also addressed all the above issues with an integrated policy by linking the RHI payments with its Microgeneration Certificate Scheme (MCS).  The MCS aims to bring Britain’s biomass technology industry into line with the more stringent European standards.


For wood pellet boilers, the RHI falls into two categories: the Domestic RHI and the Non-Domestic RHI.

The Domestic RHI is basically designed to help customers ‘earn back’ the cost of their wood pellet boiler through tariff payments of 12.2p per KwH (index-linked) over seven years.  Both biomass boilers and biomass pellet stoves with back boilers are eligible for the payment.   Other criteria for eligibility include:

–          a Green Deal Assessment (to ensure your house is fully insulated including loft and cavity wall insulation)

–          an Energy Performance Certificate for your home.  The boiler and installer must be MCS certified (MCS covers heat generating technologies with a capacity up to 45kW).

–          The boiler must also be serviced every year to ensure that it is burning to maximum efficiency.

–          And, if your installation date is after 9 April 2014, an Air Quality Certificate is needed.  Wood pellets can be burnt in smoke controlled zones if used in a smokeless-approved appliance (nearly all pellet boilers in the UK are smokeless-approved but it is worth checking with your local council).


The Non-Domestic RHI is designed to encourage businesses to switch to biomass for their heating and is available for commercial and community installations.  The tariff aims to give 12% return on capital over twenty years and is index-linked.


In terms of planning permission in the UK, biomass heating systems now qualify as permitted development unless the flue exceeds the roof height by one metre or more.  For those who live in a listed building, it is advised to consult your local planning department to find out whether planning permission is needed.  For conservation areas and world heritage sites, it is essential that your flue is not installed on a wall or roof slope which faces a road.   Boiler installations must also comply with buildings regulations (for issues such as ventilation and noise).


Part of the Government’s approach with the RHI is to involve woodland-owners, transporters and others in the wood biomass supply chain to ensure that enough wood pellets can be supplied for the anticipated increase in demand.  These RHI-linked wood pellets need to be from sustainable sources.  This helps creates certainty for both the supplier who invests in the wood pellet industry and also the customer who will be reliant on a ready supply of wood pellets.


Widespread expertise regarding wood pellet systems in the UK still has some way to go before catching up with that of our European counterparts, but the new regulations and incentives mean that the UK is starting to enjoy tapping into its wood-pellet market with increased confidence.  Finding a reputable, MCS-certified installer in your area and doing ‘homework’ to identify your wood pellet boiler needs can help ensure that your venture into this technology of the future runs smoothly.


If you would like more information on how you can use biomass to heat your home or business then go to


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