Role of fossil fuels in electricity generation and their environmental impact

Approximately 70% of the world´s electricity is generated by the combustion of fossil fuels and there is consequential environmental impact due to the production of the fossil fuels and their transportation as well as from their combustion. In 1992, the solid fossil fuels are the major fuel for electricity generation and are responsible for 58% of the electricity generated from fossil fuels; natural gas accounts for about 23% and fuel oils for 19%. The scene however is shifting towards a greater use of natural gas and by the year 2000 it could provide 25-30% of the world electricity output, while the amount of fuel burned will have decreased. The reason for this scenario is simply that the combustion of coal can cause a considerable amount of pollution compared to natural gas. The environmental impact of these fossil fuels in relation to electricity are considered together with the available methods of emission control. Cleaner coal technologies to reduce the emission of NO_x, SO₂ and CO₂ are described and include fluidised bed combustion and an integrated gasification combined cycle. There is no SO_x problem with natural gas and NO_x is controlled by injecting steam or water into the gas turbine inlet.