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General News of Sunday, 26 November 2000

Source: Accra Mail

Aboadze Power Project

A 330-megawatt thermal power generating plant was recently inaugurated at Aboadze, 17 kilometres east of Takoradi in the Western Region as part of a project which started 5 years ago to diversify the country's sources of power.

Some concerns have been raised in the Ghanaian media about the environmental impact of the project. I intend, in this article, to discuss in broad terms the potential environmental and health consequences of a project like the Aboadze Thermal power-generating project.

It is not my intention to challenge the usefulness of the project but to highlight some of the potential environmental problems associated with thermal power generating plants that Ghanaians should be aware of. From the environmental economics perspective of benefit/cost analysis, this project will be deemed to be viable and beneficial if the anticipated benefits of the project in monetary terms is equal to or greater than the negative environmental and health effects valued in monetary terms plus the actual cost of the project. I am not going to undertake that kind of exercise here.

Thermal power generating plants, also called fossil-fuelled power plants, are known to adversely affect air quality and climate change. They emit gases such as Sulphur dioxide (SO2), Nitrogen oxides (NOx), Particulate Matter (PM10 and PM2.5), Volatile Organic Compounds (VOC) Carbon monoxide (CO) all of which affect air quality and Carbon dioxide (CO2) which is responsible for global warming and climate change. All fossil-fuelled power plants emit these gases. However, the degree or intensity of the emissions depends on the kind of fuel used to generate the power. Coal fired thermal plants are the worse emitters while the natural gas-fuelled ones have the lowest emissions.

The Aboadze plants are designed to burn Light Crude Oil (LCO) and natural gas and therefore emit all the pollutants I have identified above. What, then are the environmental and health consequences of these pollutants? While it is not possible to discuss the potential environmental and health effects of the Aboadze project per se because of my limited knowledge of the project, I will be able to discuss the effects of these pollutants in more general terms. To fairly discuss the potential environmental effects of Aboadze, one will need to know the kind of end-of-pipe technologies installed on the plants, the kind of burners that are used (e.g. whether they are low NOx burners or not) and the sulphur content of the LCO in use at the plant. Generally, low sulphur containing crude oil is more expensive than high sulphur containing one. With the current escalating cost of crude oil, my guess is that the LCO being used at the plant is high in sulphur.

SO2 and NOx are acid gases responsible for acid rain. Many studies undertaken in different jurisdictions have shown acid rain to be damaging to vegetation and crops. The geographical location of Aboadze close to Ghana's major remaining tropical forest located in the southwestern part of the country is a source of concern to many environmentalists. While it can be argued that the CO2 generated by the plant will be absorbed by the forest and thus reduce its global warming effects, the acid rain has the potential to damage the forest. Another likely effect is that the NOx will react with the VOC through the action of sunlight to produce ground level ozone responsible for smog which has been found in many epidemiological studies to be responsible for premature deaths among children, elderly and asthmatics. Smog is also known to kill plants and animals.

Most of the Particulate Matter emissions associated with fuels such as LCO and natural gas are less than 2.5 microns. Particulate matter less than 2.5 microns are referred to as PM2.5 or sometimes called respirable particulate matter. These particles are so small that when inhaled by humans remain in the lungs. Epidemiological evidence indicates that PM2.5 is a health hazard and can cause premature death. CO is also known to be a toxic gas that has caused many deaths. CO2 is widely recognized by the scientific community to be an atmospheric ozone depleting substance and therefore responsible for global warming and climate change. While on the one hand it may be argued that the tropical rain forest may serve as a sink for the CO2 emitted at Aboadze, it can also be argued on the other hand that the damaging effects of the acid rain may prevent that process.

In terms of the environmental health of a country, thermal power generating plants are not the best to generate electric power. Ghana abounds with vast potential sources of renewable energy that should be developed and harnessed to satisfy the energy consumption needs of the country.