Introduction to Biomass & Biofuels
The term Biomass most often refers to organic matter such as timber and crops grown specifically to be burnt to generate heat and power.
Biomass is sustainable and generally carbon neutral because the carbon released in the combustion process is offset by the carbon trapped in the organic matter by photosynthesis during its growth. To be truly carbon-neutral we need to make sustainable use of plants or trees as fuel, and replant them as we harvest them - so that the carbon is reabsorbed in a continuous and virtuous cycle.
The most popular UK biomass crops are coppice, willow and poplar, Miscanthus (Elephant Grass), Reed Canary Grass and Oil Seed Rape.
As well as specifically grown crops, other agricultural by-products are also referred to as biomass, such as straw, grain husks, forest products, waste wood and animal wastes such as slurry and chicken litter.
Biomass Task Force
In October 2004 the Government asked the Biomass Task Force to suggest measures to optimise the contribution of biomass energy to renewables, sustainable farming, forestry and the rural economy. Their report can be downloaded from the DEFRA website at http://www.defra.gov.uk/farm/crops/industrial/energy/biomass-taskforce/index.htm
The UK has the world’s largest and most efficient straw fired power station in Cambridgeshire. The 36MW plant generates over 270 GWh of electricity a year; enough power to heat and light 80,000 homes. The power station consumes around 200,000 tonnes/year of straw collected from farms within a 50 mile radius.
Domestic & Community Biomass
As not many of us have the room to grow biomass crops, the most popular use of biomass domestically is in wood burning stoves for water heating and space heating.
Emissions from wood used as fuel contain virtually no sulphur dioxide and very low levels of nitrous oxides, so won't cause acid rain. If wood is seasoned for two years and burnt efficiently it gives off very low amounts of smoke particulates and the ash is an excellent fertiliser. Larger stoves are often fitted with a ‘Lamda’ sensor, which regulates the amount of oxygen added, and so optimises combustion efficiency.
The use of wood pellets, which are usually made of highly compressed waste sawdust, for heating is well established in countries such as North America, Sweden, Austria and Denmark. There is now an emerging pellet industry in the UK and there are currently two UK manufactures of wood pellet boilers based in Suffolk and Staffordshire.
Useful sources of Biomass information:
The Log Pile Website is the National Energy Foundation’s initiative to promote the use of wood as a source of renewable energy and sustainable heating. www.nef.org.uk/logpile
The Biomass Energy Centre is the Forestry Commission’s website dedicated to promoting Biomass fuels: www.biomassenergycentre.org.uk
Biofuels and Biogas
The terms Biofuels and Biogas refer to fuels derived from Biomass, from agricultural and domestic waste and by anaerobic digestion of sewage such as
- Biodiesel and
These fuels can be burnt to produce heat and power, used to run vehicles (Brazil has the highest proportion of road vehicles designed to run on biofuels which peaked at 90% in the 1980s) or powering fuel cells.
All existing vehicles are able to run on a 5% blend. Flexible fuel vehicles are able to use blends of up to 85% biofuel.
In Europe the most common Biomass crops grown for conversion into biofuels are Oil Seed Rape, Flax Seed, Sugar Beet, Wheat, Soybeans and Corn.
In December 2005 British Sugar announced that it had begun construction of a £20million plant in Norfolk to convert locally grown sugar beet into biofuel. Biobutanol can easily be blended with conventional grades of petrol and can already be used at concentrations up to 10% without any modification to existing vehicle technology. British Sugar has contracted to sell this biofuel through Greenergy owned 25% by Tesco so you will soon be seeing fuel containing biofuel from sugar beet at your local supermarket.
The Renewable Transport Fuel Obligation Programme
The Renewable Transport Fuel Obligation Programme (RTFO) will, from April 2008, place an obligation on fuel suppliers to ensure that part of their aggregate sales is made up of biofuels by 2010.
The effect of this order will be to require that 5% of all UK fuel sold on UK forecourts will come from a renewable source by the target date. The RTFO will help bring the UK into line with European Union biofuels directive.
The RTFO Administrator will formally come into existence once the RTFO Regulations are approved by Parliament in late 2007 and will issue RTF Certificates according to the quantity of renewable fuel on which duty has been paid. It will be possible for companies to trade certificates.
Detailed information on the scheme can be found on the Department for Transport's website: http://www.dft.gov.uk/pgr/roads/environment/rtfo/
Biogas typically refers to a (biofuel) gas produced by the anaerobic digestion or fermentation of organic matter including manure, sewage sludge, municipal solid waste, biodegradable waste, agricultural slurry or any other biodegradable feedstock, under anaerobic conditions. Biogas is comprised primarily of methane and carbon dioxide.
The harvesting of methane and carbon dioxide has a double benefit – they are greenhouse gases so allowing them to escape will add to Global Warming whilst the gas itself can be used for heat and power. Landfill gas is typically 50-60% methane, 25-35% carbon dioxide and the rest a mixture of oxygen, hydrogen, nitrogen and hydrogen sulphide. Biogas can also be cleaned to be identical in characteristics to natural gas and fed into the gas distribution network.
In England, the Energy Crops Scheme provides grants for establishing short rotation coppice and miscanthus. The scheme is now closed for applications. The Government has agreed in principle to support the establishment of energy crops under the new Rural Development Programme, which will run from 2007-2013, and is currently considering how best to take this forward. The nature of the support may be different from that currently provided.
Farmers can also receive the Single Payment for energy crops grown on set-aside. An annual aid payment of 45 euros per hectare is available for growing energy crops on non set-aside land. More detailed information can be found on the Rural Payments Agency website under Energy Aid.
The Bio-energy Infrastructure Scheme helps develop the supply chains required to harvest, store, process and supply energy crops and wood fuel to energy end-users.
Biomass-fuelled stoves for space heating, central heating and hot water systems are included in the DTI's UK-wide Low Carbon Buildings Programme started on 1 April 2006 which supersedes the previous Clear Skies Initiative and Solar PV programmes. See the Grants page on this website for details.
A new support scheme for biomass heat in the industrial, commercial and community sectors will be introduced in 2007. The scheme will be worth at least £10-15m in England over the first two years and will run for a total of five years.