IMPACT OF FOSSIL POWER PLANTS ON AIR QUALITY

Abstract

South Africa has abundant supply of coal, about half being used in generation of electricity. Use of low grade high ash coal results in about 25% leaving boilers as PFA but ESP's lowers quantity emitted to air considerably.

Lower sulphur coal increases ash resistivity, inhibiting precipitator effectiveness. Various solutions tested by Eskom through the 80's include electrical improvements and ash modification. S0₃ injection equipment is effective at two Eskom stations in reducing dust emission to acceptable levels. General perception of poor dust emission is a stack that has visible emission. This could be a subjective view without real basis.

Gas emissions include vast volumes of SO_X and NO_x, with no steps taken to attenuate. Then is obviously a difference between high level and pound level phenomena. It was previously assumed that emission of pollutants via tall stacks above inversion layers into the jet-stream would avoid pollution problems. This does not appear in practice to have resulted, as low level haze appears to be increasing and impact of high level gas emission is now being investigated. Installation of gas removal plant may help the air quality, but may be unaffordable.

Greater demands for wealth and jobs results in greater industrialisation, with accompanying pollution products. Also, provision of living wages and housing scheme benefits has seen development of whole new black residential areas where coal is not burned, giving clean air living areas for these people and their neighbours.