Biomass is essentially non-fossil matter such as flora; fauna or any organic material which when used along with their by-products can produce biomass energy.
Biomass fuels can be used to create energy directly or indirectly – they can be used as a heat source in their own right or can be burned to produce steam in order to produce electricity – the latter being more suited to a commercial process than a domestic environment.
As well as thermal uses of ‘dry’ biomass fuel sources, ‘wet’ fuel sources can also be biologically converted (‘bio-conversion’) in order to produce other chemicals and fuels.
The use of biomass fuels is known as a carbon neutral process; in other words, the CO2 that is released during the production of energy from biomass (by burning or otherwise) is offset by that which is absorbed during the production of the fuel itself.
The term densification essentially refers to the practice of compacting biomass fuels. Most biomass fuel sources such as wood or sawdust would usually have a low energy density and contain a lot of unwanted air - and compacting them into pellets or other more dense formats by reducing this unwanted air content not only ensures that stored biomass fuel sources are more compact and have a greater energy density but also makes handling and transportation easier and much more efficient. Once biomass has been densified, it can be used in applications such as pellet burning stoves in the home. From an industrial or commercial perspective it can be burned alongside coal in commercial furnaces and power stations.
This is the conversion of biomass fuels in order to create a comparatively clean and combustible gas. Gasification is accomplished by heating biomass fuels in the absence of oxygen or with only a fraction of that required for combustion to take place. The resulting ‘syngas’ which is a mixture of hydrogen and carbon monoxide can be burned much more cleanly than the raw biomass sources that it is derived from. Catalysts can be added during the process that will enable other compounds to be formed, such as Methanol which can also then be used as a fuel. These are of course industrial processes and would have little relevance to the domestic environment were it not for the possibility of running cars and other vehicles on these fuel derivatives.
Domestic biomass applications
There are two main ways in which one can introduce biomass energy production into a small-scale domestic environment and they are boilers and stoves (stand alone and with back boilers).
Stoves can be used to heat a room and if fitted with a back boiler, they can also produce hot water. Typically one would use wood pellets, and/or wood logs and one could expect output to be in the 6-12kW range. This form of producing heat energy is one of the most aesthetically pleasing and a long burning stove can often be the centrepiece of the home.
In order to make a determination as to whether using a biomass powered boiler or stove is viable, one must ascertain whether there is enough space within the property to accommodate the system itself along with room for refuelling and also room for the fuel.
You should also take into account that the flue will need to be modified to allow for a wood-burning appliance.
As well as physical requirements, there are also regulatory and planning requirements to be considered. Before a flue could be fitted you will need to check with your local planning office if your property is listed or resides within an area of outstanding natural beauty (AONB). It is necessary to have a professional installation of the equipment as per section J of the Building Regulations, and it is important to note that under the Clean Air act, wood can only be burnt under certain circumstances.
The cost for a stand-alone room heater would be between £1500 to £3000 for the equipment and the installation. The cost for a boiler based on a 20kW pellet-burning boiler would be roughly £5000 to £6000 for the equipment and installation.
Unlike other forms of renewable energy such as solar and wind, it is necessary to pay for the fuel to power your system, therefore, on an ongoing basis; this option would seem to be a less cost effective method. However, this can be partially offset by the relatively low fee for the initial equipment and installation, and the fact that this form of power can aesthetically augment your home.
As the biomass fuel can be derived indirectly from industrial, commercial, domestic or agricultural products it may be possible to forge a deal with a local farm or business to provide you with biomass material that would otherwise be dropped at a local landfill site, thus helping to provide an efficient and environmentally friendly waste management solution.
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