Siemens is installing the world’s highest output gas turbines at E.ON Energie’s Irsching site in Bavaria, Germany. The company is building two combined cycle power plants known as Irsching 4 and Irsching 5 on a turnkey-basis.
Irsching 4 is a 545MW unit planned for 2011. Irsching 5 was commissioned in May 2010 after two years of construction. It is an 847MW CCGT with efficiency above 60%. The new SGT5-8000H is the world’s largest and most powerful turbine. The order was approximately worth 450m. The natural gas plant will supply power to a population equal to the size of Hamburg.
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The order was approximately €450m and the natural gas plant will supply a population the size of Hamburg.
Siemens built the plant on the site of an existing power station in Irsching near Ingolstadt. Units 1 and 2 (151MW and 312MW respectively) are in cold reserve, while Unit 3 supplies 415MW.
Development
Since 2000, E.ON has withdrawn more than a dozen small and obsolete generating units and replaced them with more efficient coal-fired and gas-fired units. More than half the company’s 2007-2009 investments will go towards building or modernizing existing power plants. The new Irsching 5 unit is being built in collaboration with the regional utilities N-ERGIE (Nuremberg) and Mainova (Frankfurt am Main).
The project was ordered by Gemeinschaftskraftwerk Irsching , which is jointly owned by power supply company E.ON Kraftwerke (50.2%), N-ERGIE (25.2%), Mainova (15.6%) and HEAG Südhessische Energie AG (HSE) (9%). The order includes a long-term maintenance contract.
Siemens is supplying the gas and steam turbines, generators, heat recovery steam generator and electrical and control systems.
The 440t gas turbine was transported from Berlin in May 2007, first on an inland waterway barge, then on a low-loader. It is 13m long and 5m high with 7000 individual parts. Its blades can withstand temperatures of almost 1,500°C.
The Irsching plant is a prototype for the new turbine. Around 250 Siemens technicians and engineers worked on the project, while another 500 employees were involved in production.
Siemens invested a total of around 550m in machine development and construction, financing and validation. The power plant created about 20 new jobs at the Irsching site.
Siemens gas and steam turbines
The high efficiency turbine is based on a combined Siemens and Westinghouse gas design and will compete against GE’s H System and Alstom’s GT24/26 high-efficiency models. The SGT5-8000H will initially deliver 340MW at 50Hz. It is designed for 250 annual starts and can reach full capacity in 30-40 minutes.
The high efficiency turbine is based on a combined Siemens and Westinghouse gas design and will compete against GE’s H System and Alstom’s GT24/26 high-efficiency models. The SGT5-8000H will initially deliver 340MW at 50Hz.
Simple cycle efficiency will be 39% and combined cycle efficiency over 60%. The turbine will be air-cooled and will use a new compressor with advanced blade design and excellent sealing for low-cooling air leakage.
Fast start-up and cycling will supply intermediate loads and turndown has been improved to increase efficiency and reduce emissions at part load.
The turbine has an axial 13-stage compressor with high mass flow, CDA (Controlled Diffusion Airfoil) front stages and HPA (High Pressure Air) rear stages. It has variable guide vanes and cantilevered stator vanes. There is a single tie-bolt rotor with compressor and turbine disks and HCO (Hydraulic Clearance Optimisation).
The high efficiency comes from a number of factors including advanced sealing to cut air leakage and advanced compressor blades. The high pressure (170 bar) and high temperature (600°C) combined cycle process uses a Benson boiler. Using air rather than steam cooling brings fast start-up times, with lower complexity in engine and plant leading to more flexible operation.
