POLLUTION FROM COAL USE

More than three-quarters of South Africa's energy comes from coal, approximately half of which is used to generate electricity, a quarter to produce synthetic liquid fuels and another quarter directly by industry and in homes. Air pollution problems from coal combustion are serious. Medical studies are revealing increased rates of respiratory disease in residents in polluted areas.

ACID RAIN

Most of South Africa's power stations are concentrated within a 100 km radius in the Eastern Transvaal Highveld and this leads to pollution problems. While all of Eskom's coal-fired power stations are fitted with electrostatic precipitators to remove dust and particulates from waste gases produced during coal combustion, none are fitted with flue-gas scrubbers (cleaning equipment) to remove oxides of sulphur and nitrogen. Tall chimney stacks in power stations assist in releasing oxides of sulphur and nitrogen into the upper atmosphere where atmospheric conditions are more favourable for their dispersal and dilution. Although this reduces ground level concentrations of these pollutants, they may combine with moist air and rain at higher levels and cause acid precipitation in areas far from the source of pollution.

Whilst South Africa's coal has a relatively low sulphur content there is considerable concern about the potential environmental and economic impact of acid rain. Half of South Africa's agriculturally productive land, half of its commercial forests and a quarter of its surface water runoff are in the Eastern Transvaal Highveld region.

POLLUTION FROM VEHICLES

Motor vehicle fumes make air pollution problems worse and are a principal cause of photochemical smog in cities. There are now plans to introduce unleaded fuel and the installation of catalytic converters which will result in a significant reduction in the release of carbon dioxide, hydrocarbons, and nitrogen oxides. However, South Africa lags far behind other countries (e.g. Japan, Germany) in legislation to control vehicle emissions. Solutions to transport pollution and vehicle congestion require long-term planning to introduce efficient public transport systems in our cities.

DEFORESTATION

Another environmental concern associated with energy use is the reliance by nearly half of all South Africans on fuelwood, once a renewable resource, but now being used at a rate much greater than that at which it is naturally regenerated. Fuelwood is an inefficient source of energy for cooking and heating and its use can cause increased respiratory illnesses. It has been estimated that if current consumption trends continue, all natural woodland in the former "homelands" will be denuded by 2020 AD. Some 500 000 ha of forest must be planted by the turn of the century if this situation is to be reversed. However, before this time, it is likely that a significant number of people will switch from wood as a source of fuel to more convenient sources such as paraffin, gas and electricity, thereby slowing down the rate of deforestation.

GLOBAL WARMING

South Africa uses a great deal of energy, very much more per unit of gross domestic product (GDP) than most other countries. The combustion of coal, oil and wood results in increased carbon dioxide production. This gas acts likes a greenhouse - it lets short-wave, natural light through but traps out-going long-wave (infra-red or heat) radiation. The potentially devastating consequence is that the earth is slowly getting warmer, causing the climate to change and sea levels to rise (see Enviro Facts "Global Warming"). Although South Africa produces only a small percentage (1,6%) of the total, global carbon dioxide emissions, it plays a disproportionately large role per person in contributing towards the greenhouse effect and global warming. As a country needing rapid economic growth in the medium term to satisfy the country's developmental needs, South Africa's potential contribution to global warming is an area of concern.

NUCLEAR ENERGY

South Africa currently has one commercial nuclear power station at Koeberg near Cape Town. It provides 1 800 MW of Eskom's installed electricity generation capacity of 37600 MW, less than 5% of the total.

Electricity planners foresee that as electricity demand grows, very many more nuclear power stations will be built. Nuclear fission produces dangerous radioactive by-products. There is considerable concern about their safe containment in the case of accidents at nuclear power stations, the closing down (decommissioning) of old power stations, and the storage of highly toxic wastes. At present, low-level radioactive wastes are stored in sealed containers which are buried underground at disposal sites. No long-term solution has been agreed on for the safe storage of high-level radioactive wastes, some of which remain harmful for thousands of years.

TOPICS FOR DEBATE

* As there is no conclusive proof of significant damage to agriculture or forestry in the Eastern Transvaal from acid rain, should South Africa invest in expensive flue-gas scrubbers?

* Given the huge development challenges South Africa faces, including providing greater access to electricity for poorer urban and rural households, can South Africa afford to spend money to reduce the possibility of acid-rain, or reduce its contribution to global warming? Can we afford to spend money on catalytic converters to reduce vehicle emissions?

* Given the environmental cost associated with coal combustion, should South Africa's next power station be nuclear?

FURTHER READING

ATMOSPHERIC POLLUTION AND ITS IMPLICATIONS IN THE EASTERN TRANSVAAL HIGHVELD. P. D. Tyson et al. SA National Scientific Programmes Report No 150, CSIR. 1988.

GOING GREEN: PEOPLE, POLITICS AND THE ENVIRONMENT IN SOUTH AFRICA. J. Cock and E. Koch (eds). Oxford University Press, Cape Town, 1991.

SOUTH AFRICAN ENVIRONMENTS INTO THE 21ST CENTURY. B. Huntley, R. Siegfried and C. Sunter. Human, Rousseau and Tafelberg, Cape Town, 1989.

BACK TO EARTH. J. Clarke. Southern Books, Johannesburg, 1991.

Enviro Facts: Global Warming, Deforestation

CONTACT ORGANISATIONS

Atomic Energy Corporation. PO Box 582, Pretoria, 0001. Tel. 012-316 3270

Chemical Workers Industrial Union. PO Box 3219, Johannesburg, 2000. Tel. 011-331 6861

CSIR: ENERTEK. PO Box 395, Pretoria 0001. Tel. 012-841 4946.

Energy Research Institute. UCT, Private Bag, Rondebosch 7700. Tel. 021-650 3230

Eskom. Megawatt Park, P O Box 1091, Johannesburg, 2000. Tel. 011-800