Gersteinwerk power plant
Gerstein power plant, unit K
One of the world's most modern plants
After some five years of construction the combined-cycle unit went on stream in October 1984 at the Gersteinwerk location. The steam power plant, originally designed for German hard coal, is, thanks to its combination with a gas turbine, one of the most efficient conventional power plants.
Gas-turbine combined-cycle plant
The gas turbine upstream of the steam power plant is operated with natural gas and discharges its exhaust gases to the furnace of the steam generator. The 480°C hot exhaust gases still contain so much oxygen that they can be used for the combustion of the coal. This technology enables an efficiency of 42% to be obtained. The electric net capacity of the units amounts to 720 MW and is composed of 112 MW gas-turbine capacity and 608 MW steam-turbine capacity. The combined-cycle operations can be switched over to fresh-air operations by switching off the gas turbine, and vice-versa, during current operations.
In the course of time, steady improvements have been made to meet the requirements of the environment and the market. Hence, the unit is now in a position to use exclusively imported hard coal. In addition, the control systems were renewed in 2011, so that the production process is fitted with the most modern technology for controlling and monitoring the plant. Thus, RWE Power AG has a highly flexible, market-oriented production unit at its disposal.
If efficiency of 42% is itself resource-sparing, fuel costs for the generated kilowatt hour can be further reduced by the input of substitute fuels instead of hard coal. Up to 10% of the furnace thermal rating can be covered by the substitute fuel. The flue-gas scrubbing plants meet strict clean-air demands, and the values required by statute are even undercut. The clear targets on environmental protection and resource preservation are documented by the Gersteinwerk location in its environment management system. Since the year 2000, the power plant has been certified according to DIN EN ISO 14001.
Gerstein power plant, unit F-I
The four natural-gas units were commissioned at the Gersteinwerk location in the years 1972 – 1973. In those days already, the units were fitted according to the efficiency-enhancing combined-cycle principle, so that they are the precursors of modern combined cycle gas turbine technology.
Special features of the power-plant technology
The combined-cycle process is a special feature of power-plant technology: upstream of the steam power plant is a gas turbine whose 420 °C hot exhaust gases are conducted to the furnace of the steam generator. The exhaust gases still contain so much oxygen that they can be used for the combustion of the natural gas. This technology enables net efficiency of 41% to be obtained and goes far to help save resources: the greater the efficiency, the less primary energy is needed per kilowatt hour produced. In this respect, natural gas as a primary energy carrier sets standards in clean air. Also, the gas turbines are rapid-start and can be feeding the electricity grid within a quarter of an hour. Altogether, each unit can feed 410 MW into the public electricity grid, with 55 MW being accounted for by the gas turbine and 355 MW by the steam turbine.
Dispatch of combined-cycle units changed
Against the background of the enormous increase in renewable resources (wind energy und photovoltaics) during recent years, the dispatch of combined-cycle units has changed today. The units remaining are making their contribution toward compensating for any shortage in the feed-in of renewable electricity and acting as rapid standby reserve.
Gas pipe array
The supply of the Gersteinwerk plant is via a high-pressure gas pipeline of its own from the central distributor station Werne to the power plant. This connecting line ends in a gas pipe array located in the immediate vicinity of the power plant. This some 9-km-long subterranean pipe with a diameter of approx. 1.40m can take up some 1 million cubic metres of natural gas. This is equivalent to the quantity that a natural-gas unit needs for 10 hours full load operations. With this gas supply, fuel procurements on the international gas market become more flexible, since price fluctuations cannot have unchecked effects. Hence, the pipe array acts as buffer in