Energy crops and cropping, their place in uk agriculture and farming

Energy Crops in Agriculture – an introduction

Energy crops are farm-grown crops that can be used to provide heat, electricity and transport fuel. Energy crops produce renewable energy (often considered carbon neutral) and can be broadly divided into those grown for power generation and those grown for transport fuels. Energy and fuels produced from biological matter (biomass) are prefixed with the word bio, hence bioenergy (for power) and biofuel (for transport).

Bioenergy - the main crops grown for power generation:

Miscanthus (Elephant Grass) is a perennial energy crop that resembles bamboo. It is harvested annually and the chopped crop can be burnt or gassified to produce heat and electricity.

Willow Short rotation coppice consists of willow or poplar species that are harvested every three years to produce wood chips that can be burnt or gassified to produce heat and electricity.

Maize Maize and other whole crop silages can be converted by anaerobic digestion into a biogas that can be used to produce electricity and heat.

Biofuels - the main crops grown for transport fuels:

Oilseed rape is grown for the production of biodiesel. Biodiesel is a natural replacement for mineral diesel. Normally biodiesel and mineral diesel are mixed to produce a blend.

Wheat Wheat and other cereal crops can be grown for the production of bioethanol that can be blended with petrol.

Sugar Beet can be grown for the production of bioethanol and biobutanol, both being blended with petrol.

Despite media and political interest, the use of energy crops in the UK remains in its infancy and far behind that of many other countries. However, energy cropping in agriculture is just a part of the bigger biomass picture. Biomass is also derived from forest residues and wastes (straws, slurries, sewage, food etc), all of which can be used to produce bioenergy. The EU estimates that by 2010 around 60% of EU bioenergy will be produced from waste with agriculture and forestry producing about 20% each. However, over the following decades most of the increase in bioenergy production will come from agriculture with energy crops playing an increasingly important role on farm.

Although energy cropping is often regarded as a new activity, it should not be forgotten that for most of the past 6000 years, coppicing provided our ancestors with a sustainable source of wood for heat. It is only in the last two centuries with the adoption of cheaper and more convenient alternatives that the sustainable practice of coppicing has been displaced.