Biomass refers to the biological material derived from living, or recently living organisms.
In the context of biomass for energy the term is often used to mean plant based material, but can also apply to both animal and vegetable derived material.
Biomass is a key building block of biofuels – it can be specially grown for electricity production or to produce heat in the energy context, as an alternative to fossil fuels.
Biomass is composed largely of carbon, hydrogen and oxygen. Nitrogen and small quantities of other atoms, including alkali, alkaline earth and heavy metals can also be found. Biomass is the building block or ‘feedstock’ for many other fuels.
The key difference between biomass and alternatives like fossil fuels is the difference between the time it takes to replenish the source of each. 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 agricultural management 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.
In contrast, when a fossil fuel is burnt the CO2 in the atmosphere increases as it takes hundreds of millions of years for the fossil fuel source to be replenished.
What sources of Biomass are there?
Biomass energy is derived from five quite distinct energy sources: garbage, wood, waste, landfill gases, and alcohol fuels. Most biomass still relies on incineration – burning – and to this end forest residues such as dead trees, branches and tree stumps, yard clippings, wood chips and garbage are often used.
Biomass nowadays tends to also include plant or animal matter used for the production of fibres or chemicals, and may also include biodegradable wastes that can be burnt as fuel.
Industrial scale biomass is now readily being grown from numerous types of plants sources, including sugarcane (bagasse), native grasses, miscanthus, switchgrass, pongamia, hemp, corn, pine, bluegum, poplar, willow, sorghum, and a variety of tree species, ranging from eucalyptus to oil palm (palm oil). The particular plant used is usually not important to the end products, but it does affect the processing of the actual raw material and often the types of technology used to do this.
Wood energy is derived both from the direct use of harvested wood as a fuel and from wood waste streams. The largest source of energy from wood is pulping liquor or “black liquor,” which is a waste product from the industrial processes of the pulp, paper and paperboard industry.
Because biomass is basically a feedstock or building block which can be converted to energy, it is potentially able to power everything from cars and trucks to airplanes and conventional power stations. Have a look around our website to see the wide variety of potential end users.
Biomass can be converted to energy in many different ways, including direct combustion, gasification, combined heat and power (CHP), anaerobic digestion and aerobic digestion.
Advanced biofuels are now converting biomass directly into petrol, diesel and jet fuels and represent a new growth area as technology develops.