Biomass is a renewable energy source and is biological material from living, or recently living organisms such as trees, plants crops, etc. The fuel can also obtained from human waste and landfill sites. Biomass can either be used directly, or converted into other energy products such as biofuel.

In one form, Biomass is plant matter used to generate electricity with steam turbines and gasifiers or produce heat, usually by direct combustion. Examples include forest residues (such as dead trees, branches and tree stumps), garden clippings, wood chips, etc. In the second sense, biomass includes plant or animal matter that can be converted into fibres or other industrial chemicals, including biofuels. Industrial biomass can be grown from several types of plants, including miscanthus, switchgrass, hemp, corn, poplar, willow, sorghum, sugarcane and a variety of tree species, ranging from eucalyptus to oil palm (palm oil).


Using a process called gasification. Gasification involves subjecting solid biomass to hot steam and air to produce a gaseous bio fuel. This gas (also called synthesis gas) can be burned for heating, electricity production, or may be further converted to act as a substitute for almost any fossil fuel.

Synthesis gas is a better fuel than the original solid biomass and can be stored and transported more easily.

  • Affordable heating fuel: although the price of wood fuel varies considerably, it is often cheaper than other heating options.
  • Financial support: wood fuel boiler systems could benefit from the Renewable Heat Premium Payment and the Renewable Heat Incentive .
  • A low-carbon option: the carbon dioxide emitted when wood is burned is the same amount that was absorbed over the months and years that the plant was growing. The process is sustainable as long as new plants continue to grow in place of those used for fuel. (The trees used will be fully grown and therefore omit years and years of carbon dioxide whereas the trees that replace them are only saplings and wouldn't be able to absorb the carbon that a fully grown tree gives off when burnt). There are some carbon emissions caused by the cultivation, manufacture and transportation of the fuel, but as long as the fuel is sourced locally, these are much lower than the emissions from fossil fuels.

A pellet stove will cost around £4,300 including installation. Installing a new log stove will usually cost less than half this, including a new flue or chimney lining.

For boilers, an automatically fed pellet boiler for an average home costs around £11,500 including installation, flue, fuel store and VAT at 5%. Manually fed log boiler systems can be slightly cheaper. (The average home has a gas fired boiler. The cost of this so-called renewable energy boiler would only save around £100 per year. With the cost of a new Gas boiler (£2500 approximately) against the cost of this, it would take you 90 years to break even if you made savings of £100 per year) Pellet costs depend mainly on the size and method of delivery. Buying a few bags at a time makes them expensive. If you have room for a large fuel store that will accept several tonnes of pellets at a time, delivered in bulk by tanker, you can keep the cost down to around £190 per tonne in most parts of the UK.

Logs can be cheaper than pellets but costs depend on the wood suppliers in your local area as they cost a lot to transport. If you have room to store more than a year's worth of logs you can save money by buying unseasoned logs and letting them season for a year - but this requires space.

money houses

The benefits can be both financial and environmental.

Savings in carbon dioxide emissions are very significant - around 7.5 tonnes a year when a wood-fuelled boiler replaces a solid (coal) fired system or electric storage heating. Financial savings are more variable - if you replace a gas heating system with a wood-burning system you might save £100 a year, but if you are replacing electric heating you could save as much as £580 per year. This table shows how much you could save by installing pellet central heating in a typical three-bedroom semi-detached house with basic insulation:

Fuel replaced Expected saving Expected carbon dioxide saving
Electricity £580 a year 7.5 tonnes a year
Oil £280 a year 4 tonnes a year
LPG £720 a year 3.5 tonnes a year
Coal £300 a year 7.5 tonnes a year
Gas £100 a year 3 tonnes a year

A Biomass Boiler and Stove uses pellets of combustible material or wood to burn in a furnace which develops heat and heats up the water either for heating and/or hot water usage. Other products are Biomass stoves and Biogas water heaters (see top of Biomass section)

A Biomass Boiler and Stove uses pellets of combustible material or wood to burn in a furnace which develops heat and heats up the water either for heating and/or hot water usage. Other products are Biomass stoves and Biogas water heaters (see top of Biomass section)

Advantages Disadvantages
A lot better for the environment The cost of purchasing and installing these are far higher
Can save money compared to other fuel sauces available The biogas water heater version are only available for small flow rates at the moment
Grants are available to help with costs The space required for a biomass/wood boiler is far greater that anything as you need a fuel storage as well
  Regular maintenance is required to keep the efficiency up
  The fuel they burn releases carbon the plant has collected over it's lifetime. The plant that replaces the dead one will be a sapling and will not be able to absorb the carbon given off by a fully grown plant.