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In 1866, Werner von Siemens discovered the dynamo-electric principle and thus enabled electricity to be put to practical use. The dynamo can convert mechanical energy into electrical energy in an economical way. Its invention laid the foundation for today's world of electrical engineering.
In 1922, Mark Benson was granted a patent for a boiler designed to convert water into steam at high pressure. Siemens acquired the patent and developed a reliable high-pressure steam generator. The first commercial Benson boiler went into operation in 1927 in the thermal power plant at Gartenfeld in Berlin.
In 1925, the Irish Free State awarded Siemens the contract for the electrification of the entire country. The core of the supply system was the hydroelectric power plant on the river Shannon with three 30 MVA generators (commissioned in 1929). Extension of the plant was completed in 1933 (another 25 MVA).
The continually increasing voltages transmitted over power lines also made tougher demands on switching technology. Because classic oil-filled switches were liable to explode, Siemens developed an expansion circuit-breaker using water as the quenching medium. The first circuit breaker of this type was supplied to the Hamburg public utility in 1930.
Power reaches the consumer via distribution and transmission systems. The SF6 circuit breaker was introduced in 1964 in order to switch the increasingly high voltages which were being transmitted. It operated with sulfur hexafluoride (SF6) as the quenching agent.
Block A of the power plant at Biblis near Worms went into operation on a trial basis in 1974. At the time, it was the largest nuclear power plant in the world. Its output of about 1200 MW was sufficient to supply all the power then required by a city with over two million inhabitants, including industrial users.
With the use of thyristors, a breakthrough was achieved in high-voltage DC transmission (HVDC). This technology was used for the first time in 1975 to transmit power along the 1400 km route between the hydroelectric power plant at Cabora Bassa (today: Cahora Bassa) in Mozambique and South Africa.
Oil and gas-fuelled power plants based on the highly economical and environmentally friendly combined-cycle technology - which combines gas and steam turbines - are in successful operation around the world. Siemens built the combined cycle power plant at Rye House in England in 1994, which won the company the Project of the Year Award.
Fuel cells are highly efficient without giving off any emissions. They generate energy from hydrogen and oxygen by an electrochemical process. In 1994, Siemens set a world record by producing high-temperature fuel cells with an output of 1.8 kW - three times the power density previously achieved.
In March 2001, the Mainz-Wiesbaden combined cycle power plant (CCPP) goes online in Germany. The new plant has an efficiency of over 58 percent – a world record. Through the simultaneous decoupling of process steam and district heating, the CCPP also achieves a very high fuel utilization rate of some 80 percent, enabling the 400-megawatt facility to make a very substantial contribution to the reduction of CO2 emissions in Germany.
At the beginning of 2010, Siemens delivers the world's largest and most efficient 800-kilovolt converter transformer. The record-setting transformer's destination is the high-voltage direct-current (HVDC) link under construction between Xiangjiaba and Shanghai in China. With a length of over 2,000 kilometers and a transmission capacity of 6,400 megawatts, the HVDC link is the longest and most powerful in the world. For the converter station in Fulong, which is near the Xiangjiaba hydropower plant, Siemens is supplying ten converter transformers, of which five have an 800-kilovolt rating.
In 2009, Siemens completes trials at Germany's Irsching 4 power plant of the SGT5-8000H, the world's most efficient gas turbine, successfully and on time. After more than 1,500 hours in operation – of which 1,200 are at full load – and an assessment of all the measurement data, the turbine's original rated output of 340 megawatts (MW) is raised to 375 MWs in single cycle operation. In combined cycle operation, the turbine's output rises by 40 MWs to more than 570 MWs. These additional 40 MWs are sufficient to supply electricity to about 220,000 more people.
In the fall of 2012, field testing of the world's largest rotor begins at the six-megawatt offshore wind turbine in Østerild, Denmark. The rotor is equipped with the world's longest rotor blades, each of which is 75 meters in length. The turbine can generate 25 million kilowatt hours of clean electricity in offshore locations – enough to meet the energy needs of 6,000 households. Situated in a windy area near the coast, Østerild offers excellent conditions for onshore testing.