This work has proved extremely valuable in the past and is even more relevant at present, due to a new Air Quality Act that incorporates much stricter provisions than the previous air quality legislation. Analysis of air quality data is carried out using a comprehensive software package developed in-house - the Environmental Database-driven Web-Enabled Integrated System (EDWEIS). This facilitates the on-line statistical analysis and reporting of environmental data using a variety of purpose designed analysis tools and the dissemination of results to a broad spectrum of Eskom researchers via the Internet. The latest research report on ambient quality describes an investigation, that used both monitored and modelled air quality data, together with a geographical information system, to show the extent to which our power stations impact ambient air quality. The study concluded that, although there will be some areas that will need attention, the power stations will generally meet proposed air quality limits, if these limits are specifically applied to populated areas, as is the government’s intent.

In the 1980s, the reduction of particulate emissions from the coal-fired power stations was the most significant environmental challenge that we faced. Initial reductions resulted from the mothballing and closure of many of the older plants. In the late 1990s, a stringent five-year target was developed to cut particulate emissions from an average of 0,37kg/MWh to 0,28kg/MWh sent out. Between 1990 and 2003, the total annual particulate emissions were reduced from 271 000 tonnes to 57 000 tonnes, while the energy sent out increased by 64 000GWh. This was achieved while still ensuring that the optimisation of life-cycle costing was factored into all decisions made at every power station.

Relative particulate emissions per Eskom coal-fired power station

The technologies employed to manage and reduce particulate emissions include electrostatic precipitators, bag filters and flue gas conditioning.