news / 2011-05-19

Combined power plant achieves efficiency of 60.75%

Irsching sets world record marks with highest efficiency and maximum operating flexibility

The efficiency of the Irsching 4 combined cycle power plant is greater than 60 per cent. ©Siemens


Ten years after the launch of the publicly funded research programme for the new gas turbine generation, the Irsching 4 power plant with H-class turbines has set a new efficiency world record: in May 2011, engineers from the Siemens technology group measured an efficiency of 60.75% during test operation. With an output of 578 megawatts, the power plant therefore easily surpassed the targeted efficiency benchmark “above 60%”.


The predecessor generation had an efficiency of 58.5 per cent. The new gas turbine from Siemens is designed to achieve 400 MW in pure gas turbine operation and 600 MW in combined gas and steam turbine (CCGT) operation. In CCGT operation, a single SGT5-8000H turbine could supply a large city like Berlin, which has 3.5 million inhabitants, whereby the gas consumption per generated kilowatt-hour is around one third less than the average for CCGT power plants. This would therefore also cut the carbon dioxide emissions (CO2) by a third. “These are historic dimensions and a global world record,” said Michael Süß, CEO of Siemens’ Energy division. “Particularly at a time when increasingly more wind turbines and solar power systems are constantly increasing the proportion of fluctuating electricity in the grid, compensatory, quickly responding large-scale power plants are decisive for ensuring the stability of the mains grid. Our pioneering power plant impressively shows that climate protection and cost-effective electricity generation with fossil fuels can go hand in hand,” explained Süß. The new H-class plant can quickly meet demands for additional output or reduce outputs during operation. For example, more than 500 MW can be made available in just half an hour and the output during operation can be varied by 35 MW per minute.



This record performance has been made possible by perfectly harmonising the innovative gas turbine technology with the key components in the overall system, which are optimised for high temperatures and high pressures. Each turbine consists of more than 7,000 individual parts and, in the 50-Hertz version, weighs 4,400 tonnes, which is equivalent to a fully tanked Airbus A380. The inside of the combustion chamber reaches a temperature of up to 1,500 °C and the leading edges of the turbine blades attain a speed of more than 1,700 kilometres per hour, which is more than the speed of sound. In gas turbine technology, the letter “H” stands for the currently highest output and efficiency class.

Not only does Ingolstadt benefit

The heart of the plant is provided by the most powerful turbine in the world, the SGT5-8000H. It is arranged on a shaft together with the SGen5-3000W generator and the SST5-5000 steam turbine. ©Siemens

The head of the combined cycle power plant division at EON, Klaus Hammer, has commented on the success of the site near Ingolstadt: “Highly efficient and flexible gas-fired power plants like Irsching 4 and Irsching 5, which went online in 2010, are making a considerable contribution to balancing out the fluctuating electricity fed into the grid from renewable energies and are therefore making an important contribution to securing the supply in Germany.”


More than 750 Siemens employees, including 250 engineers, were involved in developing the new gas turbine and CCGT power plant. Siemens has invested more than 500 million euros in developing, constructing and operating the prototype system in Irsching, Bavaria. The company itself spent one and a half years putting the gas turbine “through its paces” there. Following a successful test run, the gas turbine system was retrofitted for 600 °C in the middle of 2009 with a Benson heat recovery steam generator patented by Siemens and a Siemens high-temperature steam turbine, and thus developed into the world’s most efficient CCGT plant. Following the test runs, EON has begun commercially operating Irsching 4 in summer 2011 as "Kraftwerk Ulrich Hartmann".

International orders

In addition to the Irsching 4 CCGT plant, Siemens has sold six of the new gas turbines in the 60-Hz version to a utility company in Florida. The first machines for this order will be delivered in 2012. In addition, Siemens has also received an order from South Korea for the construction of another turnkey, single-shaft CCGT plant in which the 60 Hz version of the new gas turbine will be used. The plant is scheduled to go into operation in 2013.


Highly efficient CCGT plants form part of the environmentally friendly technologies with which Siemens attained a turnover of around 28 billion euros in the 2010 financial year. This technology enabled 270 million tonnes of carbon dioxide (CO2) to be saved in the same period; that is equivalent to the total amount of CO2 emitted each year in Hong Kong, London, New York, Tokyo, Delhi and Singapore.


The Siemens Energy division is a global provider for generating, transferring and distributing energy as well as for extracting, converting and transporting oil and gas. In the 2010 financial year, the Energy division achieved a turnover of around 25.5 billion euros and received orders amounting to more than 30.1 billion euros. Operating earnings amounted to more than 3.3 billion euros. As of September 2010, 88,000 employees were working in the Energy division.

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