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Biomass energy explained

Biomass energy explained

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Last updated: 02 July 2021

Biomass is a popular source of renewable energy, harvesting power from various natural fuel sources including grass clippings or other waste products.

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What is biomass energy?

Biomass energy generation involves the use of organic material as fuel to produce electricity. Biomass fuels can include grass clippings, vegetable oils, dung and most commonly, wood. The use of biomass fuels is considered renewable energy as trees and crops can all be regrown, this means that the carbon released by burning biomass fuels is regained over the time it takes to grow the new crops. Some biomass fuels are made from the waste products of industrial processes. Wood pellets used in home biomass boilers are usually made from the waste sawdust produced by sawmills.

How biomass could help you

If you burn logs on a fireplace at home, you’re already using biomass fuels, but there are several ways that you can use wood to heat your home more effectively. Home wood burners come in a variety of models, ranging from wood stoves that will heat a single room to wood-pellet boilers that can power your homes central heating system. Replacing your homes old electric heater with a biomass boiler can save you up to £700 a year on your heating bill and make you eligible for payments under the renewable heat incentive (RHI).

How to use biomass energy in your home

There are two main options for using biomass energy in your home, stoves and boilers.

Wood fires stoves are used to heat single rooms or used along with a ‘back boiler’ to provide hot water as well. Wood chips, pellets and logs can all be used as fuel and require more maintenance than boilers.

Boilers are to be used in place of your existing electric, oil or gas boiler and provide central heating and hot water for your entire home. Home use boilers tend to run exclusively off wood pellets. Boilers can either be fed with pellets manually or automatically, depending on model and price.

If you're able to entirely replace your gas heating system, you can switch to a new energy deal that supplies electricity only, and save some more money in the long run.

Energy savings from biomass

Installing a biomass boiler is expensive, however, considering RHI payments and yearly fuel savings, boilers will end up paying for themselves over a 7 – 10 years. Fully automated boilers will cost anywhere between £10,000 and £17,000 for installation. Manually fed boilers will but cheaper but will require more maintenance

Fuel costs of boilers vary depending on your local supplier but tend to cost in the region of £250 per tonne for wood pellets and £100 per tonne for wood chips.

Cost of installing a biomass boiler can be offset by payments from the Renewable Heat Incentive (RHI). Payments can be anywhere between £1,000 and £1,390 per year over 7 years, depending on how energy efficient your house was before installation. To receive RHI payments, fuels must be sourced from an approved supplier on the RHI Biomass Supplier List.

Energy savings from installing a biomass boiler will depend on what boiler you already have. Biomass boilers are more efficient than most electric storage heaters and older models of oil boilers. Gas boilers and newer oil boilers are usually more efficient than a new biomass boiler, so savings will only come from RHI payments.

Old Boiler Yearly Fuel Savings (£/year)
Old Gas Boiler (G-Rated) -150
New Gas Boiler (A-Rated) -405
Old Electric Storage Heater 700
New Electric Storage Heater 255
Old Oil Boiler 240
New Oil Boiler -380

How to install a biomass boiler

It is important to make sure that your home fits certain criteria before getting a biomass boiler installed.

Fuel supply

Be sure that you have a local fuel supplier. Pellet suppliers tend to deliver across the UK whereas logs will require a local distributor. Remember, to be eligible for RHI payments, your supplier must be on the approved biomass supplier list. Check this before entering into any long-term contracts

Do you have space?

Biomass boilers units are bigger than the gas, oil and electric counterparts and extra space will also be required for fuel storage.

Biomass boilers will also need to flue to get rid of any smoke. Insulated pipes can be installed, or current chimneys can be modified to accommodate this. This might increase the cost of installation.

Planning permission

In most cases, planning permission is not required for a biomass boiler but it is still worth checking that installation work is in line with your local building regulations.


Biomass boilers require some maintenance depending on the model. Chimneys and flues will need to be swept twice a year. Ash will need to be swept regularly to prevent build-up, how often you need to do this will depend on the type of fuel you are using. Some boilers will come with an automatic ash removal system, these will only require an annual maintenance check.


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Fergus Cole

Author: Fergus Cole

Fergus is a journalist specialising in the personal finance, energy and broadband sectors. He also has a passion for travel and adventure so tries to make the most of this in any spare time he gets.

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