Coal and greenhouse effect
The disadvantages of coal should not be undervalued, even though efficient cleaning technology can be used for combustion gas emissions. The use of this technology is required by laws and directives. The emission limits of coal are at the same level as those of other fuels. Flue dust from combustion gases separated using an electric filter is used in road construction and land construction. The most significant problem is carbon dioxide (CO2). Very large development investments are in progress around the world. However, the methods are only under development and they are expensive. They can be used to combust coal with noticeably lower carbon dioxide emissions than at present.
Coal contains small volumes of heavy metals. They can be separated very efficiently in the separation of particles, and there are no substantial emissions if the European emission limits are followed. An exception is mercury which is partly released in gas form. The volumes of mercury are very minor but they may have significance for long-range transport. The reduction of mercury emissions is also being studied.
In addition to combustion gas emissions CO2, NOX, SO2, particles), the combustion of coal creates solid waste, which is mostly formed from flue dust separated using electric filters. Emissions causing acidification are controlled at desulphurisation plants using low nox fuel technologies and catalytic separators.
Parts of the waste created can be utilised in land construction, for example. Particle emissions and emissions of sulphur and nitrogen oxides can be significantly reduced with different air protection solutions. The majority of the disadvantages have been removed in the Western industrial countries. Problems are still being caused by carbon dioxide which speeds up the greenhouse effect. Global warming has many influences on the ecosystem and life forms – including humans.
When assessing the environmental effects of energy production, the environmental effects throughout the life span must be taken into account – from production and transportation to combustion, distribution and waste management.
There is no risk-free and harmless way of producing energy. The population, improved standard of living, consumption habits and industrial development have an influence on the way the production methods of energy change. The change from one energy source to another is not enough; we need to improve the efficiency of energy production and develop cleaner production methods.