Green Energy
Green energy is a term used to describe forms of energy derived from renewable sources and is therefore, by definition, sustainable.
In recent years much attention has been given to the commercial development of forms of energy which harness the natural forces of wind, wave, geothermal and solar activity. More recently, interest has been shown in the use of virgin biomass as a source of energy using specially grown crops to produce bioethanol or trees to convert into heat or power in biomass converters.
With the ever growing demand for food crops to feed the world's population there are now concerns that using valuable farmland to grow energy crops is creating competition for the land and driving up food prices.
Until recently, however, little attention has been paid to the potential available from using waste biomass to produce renewable energy. Waste management companies typically favour large combined heat and power (CHP) plants for waste disposal as a means of reducing the volume being sent to landfill. Many of these currently use incineration to destroy the waste and produce steam which can be used as a source of heat itself or to drive turbines to generate electricity. The electrical energy produced is therefore a by-product of the waste disposal process and is an inefficient means of releasing energy - typically producing less than 50% of the electrical power available from using advanced thermal treatment for CHP.