Energy Crops: an Introduction
Energy Crops are those plants that are grown specifically for future energy production. There is a wide range of possible candidate crops from microscopic biodiesel producing algae to coppiced woodlands producing large quantities of biomass every few years. Different soils and different environmental conditions means that each ecological zone must develop of range of crops suitable its conditions and requirements. Today's main end products are Ethanol, Biodiesels and Woodfuel. Tomorrow's could see all manner of GM designed crops producing a wider range of products and at higher yields.
Sugar rich plants such as beetroot and corn are cultivated as energy crops for the Ethanol market. The mandatory requirements for ethanol mix fuels such as E10 and E85 in parts of the US and the wide adoption of Ethanol in countries such as Brazil have provided the market for large scale farming practices focused on Ethanol production. Fermentation and Distillation processes underpin the main transition to purity levels of 100%.
There are many useful varieties of plants and trees which yield high quantities of oil in their seeds and fruit such as Sun Flower or Oil Palm. In addition to processing seed oil, high temperature extraction and purification processes now allow oil to be obtained from less valuable material such as agricultural residues and waste biomass. Such oil can be combusted in its pure form, but requires additives to overcome the high gel point of pure plant oils such as Soya, at which point it is termed biodiesel.
Short Coppice Rotation
The benefit of planting coppice friendly tree species such as those from the Salix genus, is that once established the same plant can continue providing biomass crops annually from a continually growing root system.