ENVIRONMENTAL ASSESSMENT OF COMBINED HEAT AND POWER PROJECTS

For a typical coal-fired power station, the overall thermal efficiency, based on gross calorific value, varies between 35 and 37%, largely depending on the age of the power station concerned. This means that almost two thirds of the energy input in the fuel is being rejected during the process of upgrading the energy from fuel to electricity. However, it is possible to operate power stations with thermal efficiencies approaching 85% in the combined heat and power (CHP) mode, where electricity and heat energy are produced. This heat may be made available as process steam for industrial complexes or in the form of hot water for use in commercial and domestic space and water heating. In the paper, an environmental assessment is made of a number of existing and potential CHP schemes. The paper, however, does not cover financial and economic evaluation.