What is BIOMASS?

	Biomass is biological material derived from living, or recently living organisms. In the context of biomass for energy this is often used to mean plant based material, but biomass can equally apply to both animal and vegetable derived material.

	Chemical composition Biomass is carbon based and is composed of a mixture of organic molecules containing hydrogen, usually including atoms of oxygen, often nitrogen and also small quantities of other atoms, including alkali, alkaline earth and heavy metals.  These metals are often found in functional molecules such as the porphyrins which include chlorophyll which contains magnesium.
	Plant material The carbon used to construct biomass is absorbed from the atmosphere as carbon dioxide (CO2) by plant life, using energy from the sun. Plants may subsequently be eaten by animals and thus converted into animal biomass. However the primary absorption is performed by plants. If plant material is not eaten it is generally either broken down by micro-organisms or burned: If broken down it releases the carbon back to the atmosphere, mainly as either carbon dioxide (CO2) or methane (CH4), depending upon the conditions and processes involved. If burned the carbon is returned to the atmosphere as CO2. These processes have happened for as long as there have been plants on Earth and is part of what is known as the carbon cycle.
	Fossil fuels Fossil fuels such as coal, oil and gas are also derived from biological material, however material that absorbed CO2 from the atmosphere many millions of years ago. As fuels they offer high energy density, but making use of that energy involves burning the fuel, with the oxidation of the carbon to carbon dioxide and the hydrogen to water (vapour).  Unless they are captured and stored, these combustion products are usually released to the atmosphere, returning carbon sequestered millions of years ago and thus contributing to increased atmospheric concentrations.
	The difference between biomass and fossil fuels The vital difference between biomass and fossil fuels is one of time scale. Biomass takes carbon out of the atmosphere while it is growing, and returns it as it is burned.  If it is managed on a sustainable basis, biomass is harvested as part of a constantly replenished crop. This is either during woodland or arboricultural management or coppicing or as part of a continuous programme of replanting with the new growth taking up CO2 from the atmosphere at the same time as it is released by combustion of the previous harvest.  This maintains a closed carbon cycle with no net increase in atmospheric CO2 levels.
	Categories of biomass materials Within this definition, biomass for energy can include a wide range of materials. The realities of the economics mean that high value material for which there is an alternative market, such as good quality, large timber, are very unlikely to become available for energy applications.  However there are huge resources of residues, co-products and waste that exist in the UK which could potentially become available, in quantity, at relatively low cost, or even negative cost where there is currently a requirement to pay for disposal. There are five basic categories of material: Virgin wood, from forestry, arboricultural activities or from wood processing Energy crops: high yield crops grown specifically for energy applications Agricultural residues: residues from agriculture harvesting or processing Food waste, from food and drink manufacture, preparation and processing, and post-consumer waste Industrial waste and co-products from manufacturing and industrial processes.
	Why use BIOMASS? Biomass is a renewable, low carbon fuel that is already widely available throughout the UK.  Its production and use also brings additional environmental and social benefits.  Correctly managed, biomass is a sustainable fuel that can deliver a significant reduction in net carbon emissions when compared with fossil fuels. Benefits of using biomass as a sustainable fuel Correctly managed, biomass is a sustainable fuel that can offer a wide range of benefits: Biomass is a “carbon lean” fuel producing a fraction of the Carbon emissions of fossil fuels.  Biomass can be sourced locally, from within the UK, on an indefinite basis, contributing to security of supply. UK sourced biomass can offer local business opportunities and support the rural economy. The establishment of local networks of production and usage, allows financial and environmental costs of transport to be minimized. There is no region in the UK that cannot be a producer of biomass. The use of biomass fuel provides an economic incentive to manage woodland which improves biodiversity.  Many biomass fuels generate lower levels of such atmospheric pollutants as sulphur dioxide, that contributes to 'acid rain'. Modern biomass combustion systems are highly sophisticated, offering combustion efficiency and emission levels comparable with the best fossil fuel boilers.
Sources of biomass Raw materials that can be used to produce biomass fuels are widely available across the UK and come from a large number of different sources, and in a wide variety of forms. All of these forms can be used for fuel production purposes, however not all energy conversion technologies are suitable for all forms of biomass. Forms of biomass and woodfuel Raw biomass typically has a low energy density as a result of both its physical form and moisture content.  This makes it inconvenient and inefficient for storage and transport, and also usually unsuitable for use without some kind of pre-processing. There are however a range of processes available to convert it into a more convenient form.  Depending on the biomass itself, and the purpose to which it is to be put, this may consist of: In this way raw biomass is converted into what can be described as a 'biomass fuel'. For example, virgin wood (above) is a simple form of biomass and for many applications may require relatively straightforward processing.  For ease of handling, transport and storage it may be cut into a number of physical forms, as best suit the requirements of the next handling or processing stage. Handling biomass Different classes of biomass fuel have different characteristics such as moisture content and size. These characteristics can be affected by transportation and storage.
	Log Stoves and Boilers Logs are a well established traditional fuel. They can be burnt in conventional stoves or in more sophisticated boilers Log Stoves Stoves are a widely available, simple technology. They are considerably more fuel efficient than open fires, and can be found in a wide variety of different shapes, sizes and designs. If you are keen to heat your house with woodfuel on a limited budget this is probably the cheapest option. Even if you only use a stove instead of your normal heating method for two weeks at either end of your heating season, you are still making an important contribution. Things You Should Know Logs have grown in popularity during recent years, so many installers have a waiting list for installation If you don't already have a chimney you will need to have a flue installed at the same time. This can cost as much as the stove itself. Even if you do have an existing chimney it may need lining. Where do you intend to get your fuel from?  Are you in a smokeless zone? If you are and you want to burn wood then your choice of stoves will be restricted to approved appliances Log Boilers Log fired boilers are a logical step up from stoves. They range from systems designed for hot air space heating to be used in workshops, run on off-cuts, to boilers designed to run domestic heating and hot water. While some systems are at the basic, simple end of the market, employing robust, reliable technology, some boiler systems are highly efficient, with sophisticated controllers offering the option of zoned heating. Things You Should Know Log boilers are almost without exception batch fed, this means that they operate with an accumulator tank, to allow for flexibility in heating demand and heat production. The system itself and bulky fuel mean that these systems are usually relatively large for the amount of heat they produce; it may be necessary to consider installing it in a shed outside the property it is to heat. Because of the bulk of the fuel used and the necessity for manual loading these systems are not suited to very large installations. Log boilers up to 80 kW are readily available Are you in a smokeless zone? If you are, then your choice of wood boilers will be restricted to approved appliances Logs can be a significant commitment in terms of moving material by hand. Ask yourself whether even if you are able to move them at the moment, is it realistic to expect that you will be able to in ten or twenty years time?