Energy from biomass is produced from organic matter of recent origin.
It does not include fossil fuels, such as oil, coal or gas, which have taken millions of years to evolve.
The CO² released during the generation of energy from biomass is balanced by that absorbed during the fuel’s production. This is called a carbon neutral process.
As long as people have had fires, biomass has been used. People have been producing energy from biomass for centuries. In many parts of the world it is still the principle source of heat.
However, modern technologies are far more efficient at extracting energy than open fires. An increasing number of fuels or feedstocks are now used.
Biomass is often called ‘bioenergy’ or ‘biofuels’. These biofuels are produced from organic materials, either directly from plants or indirectly from industrial, commercial, domestic or agricultural products.
Biofuels fall into two main categories:
SRC and high energy crops are sometimes referred to under the more general term of ‘energy crops’. These are crops that are grown specifically for energy.
These sources of biomass are then converted into useable heat, electricity or motive power using a range of conversion processes.
These include
For small scale domestic applications of biomass the fuel usually takes the form of wood pellets, wood chips and wood logs.
We are generally familiar with wood chips and logs.
Wood pellets are a compact form of wood, which have a low moisture content and a high energy density. Although, they are currently more expensive than logs and wood chip, they are easier to handle and ideal for automated systems.
The energy content of the fuel is related to its moisture content.
High moisture content will slow the combustion process, as the moisture must first boil off before the fuel can burn.
The efficiency of combustion relies on as much of the carbon and hydrogen being oxidised as possible.
Full combustion is also the cleanest process, leaving no partial combustion products like carbon monoxide, particulates or unburnt volatile hydrocarbons.
The type of heating system you choose has a direct effect on the fuel used and the storage space required.
There are four main methods of using biomass to heat a domestic property:
Stoves can achieve efficiencies of more than 80%; they produce from as little as a few kilowatts of heat to 15kW or more.
They are normally used to provide background heating whilst adding aesthetic value, as they are designed to be located in the living area of the house itself.
Although many wood-burning stoves act as space heaters only, the higher output versions may be fitted with an integral back boiler to provide domestic hot water and if required, central heating via radiators.
Biomass - Organic matter used as a fuel, especially in a power station.
Biofuel - A fuel derived immediately from living matter.
Bio - The sense is extended in modern scientific usage to mean ‘organic life’.