If there isn’t enough wind or the sun doesn’t shine, less electricity is produced. At such times, additional energy sources are called for that can be deployed flexibly and which produce low CO2 emissions, thus ensuring constant security of supply.
As well as combined-cycle gas and steam power plants, modern coal-fired power plants offer a flexible energy production solution, thus making it possible to fill energy gaps in a timely manner. Through the complete combustion of coal in the combustion chamber, the chemically bound energy is converted into heat which is used to convert water under high pressure and at a high temperature into steam. This steam then drives the turbine generator which produces electricity. The steam is then cooled in the condenser, and the resulting water is used to create heat and produce electricity again in a closed circuit.
The flue gases created as a result of coal combustion are submitted to a thorough dust, nitrogen and sulphur scrubbing process. Part of the ash is removed from the combustion chamber in the form of slag and stored in a silo for re-use as a building material. The gypsum and fly ash deposits produced in the desulphurization process are also sold as marketable products. The general aim is to keep the effects on the environment down to a minimum and to introduce valuable by-products into the recycling chain.