Energy from Waste

EfW is the name often given to the thermal treatment of waste under controlled conditions in which energy is produced. This energy can either be converted to electricity to boost the National Grid and/or, at times, to provide heat in the form of hot water or steam, for use by nearby developments. In the most widely used EfW process, waste is burned on a moving grate. Air is introduced above and beneath the grate in carefully controlled amounts to ensure proper combustion. Good combustion means fewer emissions. The hot gases released are directed to a boiler to recover the heat. The combustion gases are then cleaned in several stages to a strict standard set by the Waste Incineration Directive (WID), which are monitored by the Environment Agency (EA) in England. Of the material received into the ERF only around 3% will not be recovered and will require specialist treatment. This is residual material created as part of ensuring the gases are clean. A plant facilitating the generation of electrical power and recovery of usable heat from a combustion process is termed a Combined Heat and Power (CHP) plant and it is more efficient than conventional power generation that is focused on power generation alone.