Pictures of the Future Spring 2007
Technology for the Environment – Renewable Energy Systems
Earth, Fire, Wind and Water
Siemens has a long tradition of developing sources of power for the future. Back in 1978, the company supplied the generators for the world’s biggest hydroelectric power plant, in Itaipú (between Brazil and Paraguay). Today, Siemens is a leader in many types of renewable energy systems. In the field of wind power, the first turbine in 1979 had an output of 22 kW; today the biggest Siemens turbines produce 3.6 MW) of power and have efficiency ratings of up to 45 %. About 6,300 Siemens wind power units with a total output of 5,500 MW are currently in operation worldwide. In the U.S. alone, the Power Generation (PG) Group has received orders to date for wind power projects with a total output of 1,400 MW, including 70 turbines generating 161 MW of power in Texas and several wind farms with a total output of 600 MW in Florida. The situation is similar in the UK, where Siemens will install 140 wind turbines near Glasgow by 2009. The turbines will produce 322 MW of power for up to 200,000 households. Siemens is also the world market leader for offshore wind farms. PG’s current 110-MW Lillgrund project in the Öresund strait will soon be Sweden’s biggest offshore wind farm. Meanwhile, the oceans themselves are slated to play an increasingly crucial role in the renewable energy sector. The Voith Siemens Hydro joint venture, for example, not only develops powerful turbines and generators for hydroelectric plants, but also plans to harness the power of ocean waves. The world’s first test facility in this field is already supplying power to 200 households in Scotland (see "Wave Power Plants").
Still in its infancy in Germany, geothermal power generation taps into the nearly inexhaustible reserves of heat from the earth. Here, hot water from rock formations several kilometers underground is pumped into a vaporizer, where a special device converts it into steam that is used to drive a turbine and a generator, producing electricity free of CO2 (see Interview with Willy Gehrer in Pictures of the Future, Spring 2004, and "Facts and Forecasts" in Pictures of the Future, Spring 2006). Siemens is now building the world’s most modern power plant of this type near Munich. The facility will have an output of 3.4 MW, and in the summer of 2007 it will begin providing up to 6,000 households with electricity and 20,000 households with heat.
Biomass power plants are CO2-neutral. They burn organic products like wood and waste, and release only the amount of CO2 that plants absorbed while growing. A particularly impressive high-performance biomass heating plant in Vienna produces 24 MW of electrical energy for 50,000 households and 37 MW of district heat for 12,000 households. Siemens’ portfolio of renewable energy sources also, of course, includes solar power. The company stopped developing solar cells in 2001 when it sold Siemens Solar to Shell, but it does supply solar technology. For instance, it is providing steam turbines for Nevada Solar One, a solar-thermal plant whose collectors cover an area of 1 km². The collectors focus sunlight and reflect the concentrated energy onto steel pipes filled with heat-transfer oil, which is then used to heat water in a heat exchanger. The resulting steam drives a 64-MW Siemens turbine. When it goes on line this summer, the facility will supply about 40,000 households with electricity.
Sebastian Webel