Wood or fuel derived from wood is often called biomass. It is included as renewable energy because it is organic matter of recent origin. It doesn't include fossil fuels, which have taken millions of years to be created. The CO2 released when biomass fuels are burned is balanced by that absorbed while the wood was growing in the recent past. This is therefore a carbon neutral process.
There are many wood burning boilers and stoves available, and the fuel takes the form of wood pellets, wood chips or wood logs.
There are two main ways of using biomass to heat your home:
- Stand alone stoves providing space heating for a room. These can be fuelled by logs or wood pellets but only pellets are suitable for automatic feed. Generally they are 6-12 kW in output, and some models can be fitted with a back boiler to provide water heating.
- Boilers connected to central heating and hot water systems. These are suitable for pellets, logs or chips, and are generally larger than 15 kW.
What are the costs and savings?
Stand alone stoves generally cost around £3,000 installed. Savings will depend on how much they are used and which fuel you are replacing. The cost for a typical 15kW (average size required for a three-bedroom semi detached house) pellet central heating boiler is around £5,500 - £12,000 installed, including the cost of the flue. A manual log feed system of the same size would be slightly cheaper. A biomass powered boiler could save you around £200 a year in energy bills and around 8 tonnes of C02 per year. The Energy Saving Trust gives more details on costs and savings.
Important Points
- Log boilers must be loaded by hand and may be unsuitable for some situations.
- Automatic pellet and wood chip systems are more expensive.
- Many boilers are suitable for both wood chips and pellets, although the wood chip boilers need larger hoppers
- Consult an accredited installer to provide more detailed advice.
- It is most cost effective when a local fuel source is used, which results in local investment and employment and also minimises transport miles to your home. Wood pellets currently need to be imported, but can be delivered in the Stafford area.
- You need storage space for the fuel
- Unlike other forms of renewable energy, biomass systems require you to pay for the fuel, rather than using free energy from the sun, wind, earth etc