Geothermal Electricity Booming in Germany

Less than 0.4 percent of Germany's total primary energy supply came from geothermal sources in 2004. But after a renewable energy law that introduced a tariff scheme of EU €0.15 [US $0.23] per kilowatt-hour (kWh) for electricity produced from geothermal sources came into effect that year, a construction boom was sparked and the new power plants are now starting to come online.

"Geothermal sources could supply Germany's electricity needs 600 times over," Werner Bussmann, CEO of the German Geothermal Association [Geothermische Vereinigung], told RenewableEnergyWorld.com.

He said special, cost effective technology allowed energy to be extracted from geothermal reservoirs containing low- to moderate-temperature water that are so typical of Germany.

Innovative technology is important because Germany, unlike countries such as Iceland, Italy or Indonesia, does not have volcanic activity or the associated dry steam reservoirs that can be used to produce electricity directly.

"Geothermal electricity has the advantage of being available 24 hours a day, 8000 hours a year, and this makes it a great source of baseload power," Bussmann said.

He predicted that Germany could be generating several thousands of megawatts (MW) of electricity from geothermal sources in a couple of decades. There are already four small geothermal power plants successfully operating in Germany, albeit supplying only a tiny amount of electricity.

More plants — some as big as 8-10 MW — are due to go into operation in 2009-2010 in Sauerlach, Dürrnhaar, Riedstadt, Speyer, Gross Schoenebeck and Mauerstetten. And looking 3 to 5 years ahead, there could be more than a hundred plants. About 150 geothermal power plant projects are in the pipeline representing an investment of 4 billion euros, according to the German government.

Just how soon these geothermal power plants will be built, however, depends on whether there is enough drilling equipment available to dig deep enough to hit the hotter water needed for electricity generation. At the moment, a shortage of drilling equipment is pushing up the cost for constructing a geothermal power plant, Bussmann said.

Costs of EU €30 to 40 million [US $47 to 63 million] for a 3.5 MW plant with a life-cycle of 30 years or longer are typical in Germany, he said. The price of drilling equipment accounts for 60 percent of the total cost, and this has doubled in the last 3 to 4 years.

In response, Germany's manufacturing sector is now gearing up to produce more drills, so removing a major obstacle to the future expansion of geothermal electricity. Also, the cost of building geothermal plants could fall in the next few years as more efficient technology is developed, Bussmann predicted. He said the geothermal industry could achieve a price per kWh that makes it competitive with gas and oil in 20 years time depending on how quickly the price of oil and gas increases.

The best geothermal generation opportunities in Germany are located in southern Bavaria — where water of temperatures of 140°C or hotter can be found 5,000 meters below the ground — and in the Upper Rhine region as well as in northern Germany.

The first pioneer geothermal plant to start operating in Germany is situated in Neustadt-Glewe in the north-eastern part of the country. The 230-kW combined electricity and heat power plant started up in 2003 and extracts water with a temperature of 97 °C from a well 2250 meters under the ground. It supplies 1,300 households with heat and a further 500 households with electricity.

Other plants now operating are the 3.5-MW plant at Unterhaching close to Munich, in Bavaria, which supplies 20,000 households with electricity and heat as well as Unterhaching, which is the first geothermal plant in Germany to use the "Kalina" technology that allows energy to be extracted from water of low to moderate temperatures. At that plant water is extracted at a temperature of 122 °C from a well 3,500 meters deep at a rate of 150 liters a second. Another 2.5-MW plant in Landau taps water of 150°C that is located 3,000 meters beneath the ground. Finally, an EU €17 million [US $26.7 million] 550-kW plant is due to go into operation in Bruchsal this autumn. The power plant will extract water at temperatures of 128°C from a well 2500 meters deep to generate electricity for 1000 households.

Though geothermal electricity is in its infancy in Germany, geothermal heat has been around for a long time, and its use is also expanding rapidly. In 2007, there were an estimated 130,000 geothermal heat pumps operating in residential and commercial buildings. About 25,000 to 30,000 new pumps are being added each year.

Bussmann said it costs about EU €18,000 [US $28,000] to build a geothermal heat pump for a family-sized house with a surface area of about 150 square meters in northern Germany where geological conditions make drilling easier.

Jane Burgermeiser is a writer based in Austria.