Plant Crops Bioenergy Research UK
Energy Crops
Second generation dedicated bioenergy crops in the UK
In the UK a number of high yielding non-food crops are classed as dedicated, second generation bioenergy crops. These are harvested to provide heat and electricity and in future may also be used to generate liquid biofuels. They are short rotation coppice (SRC) woody crops, Willow (Salix spp.) and Poplar (Populus spp.) and the perennial rhizomatous grasses such as Miscanthus (Miscanthus spp.), Switchgrass (Panicum virgatum L.) and Reed canarygrass (Phalaris arundinacea L.). In 2007, by far the most important bioenergy crops for commercial deployment will be miscanthus and SRC, currently accounting for 12,627 and 2600 hectares respectively of planting under the Energy Crops Scheme in England and Wales.
Bioenergy from crops is a renewable and sustainable source of energy that may be close to carbon neutral, although greenhouse gas mitigation potential and carbon footprints of these crops may vary widely. Solar energy drives the growth of green plants, in the process of photosynthesis, resulting in the production of simple and complex carbohydrates. These carbohydrates can be used as feedstock in a plethora of thermo-chemical, biological and gasification processes, producing a whole range of energy sources.
It has been estimated that some two billion people rely on biomass for primary energy of cooking and space heating. This is mostly in the developing countries of Africa, Asia and Latin America, and wood fuels account for some 14 % of global primary energy (FAO, 2007).
Biomass fuel currently accounts for about 1.5 % of electricity and 1 % of heat production in the UK (Biomass Task Force, 2005) and contributes approximately 83.3 % of the total UK renewables market. The UK has set a target for a 60 % reduction in CO2 emissions by 2050 from 1990 levels (DTI, 2003) and to achieve such cuts it has been recommended by the Royal Commission (2004) that biomass should contribute 12 % of the nation's energy by the year 2050. The UK has set a short-term commitment to generate 10 % of the nation's electricity from renewable sources by 2010. It is anticipated that in order to meet this target 1,500 MW of new electrical capacity might come from energy crop and forestry residue combustion; this would require planting approximately 125,000 ha of energy crops (Britt C. et al, 2002). In the UK an immediate to short-term strategy to meet this recommendation is the conversion of set-aside land to the production of dedicated energy crops. Set-aside accounts for up to 1 million ha of the total UK 17.5 million ha of agricultural land, but the ecosystem services offered by this land (e.g. biodiversity) should be considered in any proposed change of land use.
