The 2 main categories are:
| Woody Biomass |
Untreated wood products, forest products, energy crops and short rotation coppice (SRC) i.e. willow. |
Non-woody Biomass |
Animal waste i.e. poultry litter, industrial and biodegradable municipal products from food processing and high energy crops i.e. sugar cane & maize. |
Biomass is a very versatile material and can be used to produce heat (for space and water heating), electricity and a combination of the two.
There are 4 ways to convert it into a usable energy source:
| Burning |
This is probably the most common way to create energy from biomass. This is done to provide heat for homes and industries, but also to create steam for making electricity. Wood-logs, chips, bark, and sawdust-accounts for about 79 % of biomass energy. |
Conversion |
By using certain chemicals or heat biomass can be converted into gas or liquid fuels. A good example is India, they use cow manure to produce electricity by converting it into methane gas. |
| Bacterial Decay |
This is another way to produce methane gas, as it is produced during a natural process of bacteria feeding on dead plants and animals. |
| Fermentation |
By adding yeast an alcohol called ethanol can be produces. This is actually how beer, wine and various other types of liquor are made. |
Benefits
There are not only environmental, but also economic benefits to using biomass. When generating energy from biomass the CO2 released is balanced by that absorbed during the fuel's production. This is called a carbon neutral process. Also biomas contributes to waste management by harnessing energy from products that otherwise would be disposed of at a landfill.
A ton (2,000 pounds) of garbage contains about as much heat energy as 500 pounds of coal.
Your Home
In general there are 2 ways of using biomass to heat your home:
| Stand Alone Heater |
Provides space heating for a room. These are fuelled by wood pellets, wood chips or wood logs (unsuitable for automatic feed system) and can achieve more than 80% efficiency. They are often used as background heating, or fitted with a back boiler to provide hot water. In general they are 6 – 12 kW in output. Higher output versions can be fitted with an integral back boiler to provide domestic hot water and central heating through radiators. |
Boiler |
Provides space heating for a room. These are fuelled by wood pellets, wood chips or wood logs (unsuitable for automatic feed system) and can achieve more than 80% efficiency. They are often used as background heating, or fitted with a back boiler to provide hot water. In general they are 6 – 12 kW in output. Higher output versions can be fitted with an integral back boiler to provide domestic hot water and central heating through radiators .For a three-bedroom semi-detached house usually 20kW output is recommended. |
If you are considering installing a biomass stove or boiler, keep the following in mind:
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Make sure you have a storage space available for the fuel, with appropriate access to the boiler for loading and perhaps for the local fuel supplier. |
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The vent material must be specifically designed for wood fuel appliances and there must be sufficient air movement for proper operation of the stove. Chimneys can be fitted with a lined flue. |
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The installation must comply with all safety and building regulations. Therefore it is important to have an accredited installer help you with this. |
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Under the Clean Air Act, wood can only be burnt on exempted appliances. |
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Check with you local planning authority (Local Authority Planning Department) before a flue is fitted, especially if your building is listed or in an area of outstanding natural beauty (AONB). |
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Always get an accredited installer to provide you with more information and advice specific to your home. |
Costs
To install a stand alone heaters usually cost between £1,500 to £3,000, this includes the full installation and the commissioning.
The costs for a boiler varies depending on the size and the fuel you choose. To install a 20kW pellet boiler would cost approximately £5,000, this includes the full installation, the flue and commissioning. If you choose a manual log system of the same size, it will of course be slightly cheaper (approximately £3,500 to £4,000).
After purchase costs, there will be some running costs. These generally depend on the distance from your house to your supplier. As a general rule the running costs will be more favourable if you live in an area that doesn't have a gas supply.
Grants
There are government grants available to help pay for part of the cost of installation. Currently these have a maximum of £1,500 or 30% of the relevant eligible costs, whichever is the lower. To be eligible for a low carbon buildings grant householders must undertake a number of energy efficiency measures to ensure that they are already minimising their energy requirements - many of these measures are found in out hints and tips section. |