First order for Siemens’ 60-Hz, H-class gas turbine
H-class industrial gas turbines—the largest and newest of these machines in production—are currently in the spotlight. They promise remarkable 60+% thermal efficiency for combined-cycle gas turbine (CCGT) power plants by incorporating advanced electromechanical and thermal design and use of the latest materials.
Siemens Energy is completing a monumental, 10-year development program of its H-class gas turbine system. The commercialization process first focused on development of an internally air-cooled 50-Hz turbine (SGT5-8000H), but market needs for a 60-Hz version were also part of the product plan early on.
Design of the 60-Hz turbine system (SGT6-8000H) was scaled from the 50-Hz turbine, using input from the extensive test and validation program conducted on the latter machine at a working gas power plant—Irsching 4, near Ingolstadt, Germany (see main article). The testing program included more than 1,500 hours of turbine operation in simple-cycle mode, 1,200 of which occurred at full-load, and over 200 starts. “Harmonized design features of the turbines allow validation experience to be transferred from 50- to 60-Hz products,” said Phillip Ratliff, director of next-generation gas turbines at Siemens.
The 60-Hz turbine is rated at 274 MW output at ISO conditions (simple-cycle operation) compared to 375 MW output for the 50-Hz machine. In combined-cycle operation, these turbines are rated at 410 MW and 530 MW, respectively, while achieving over 60% efficiency, according to the company. Among attributes of these gas turbines, Ratliff cited fast start-up and cycling capability to support intermediate- to continuous-duty operation; and ability to run on gas and fuel oil, with engine emissions at 25 ppm NOx and 10 ppm CO.
Control Engineering has visited Siemens’ H-turbine test and validation site at Irsching 4. Discussions with Willibald Fischer, Siemens’ program manager for H-turbines, included the development of the 60-Hz turbine. Fischer explained that 60-Hz machines enjoy certain inherent advantages over their 50-Hz cousins, for example, smaller physical size because of higher synchronous speed. This translates to cost savings in materials and manufacturing. “It also makes possible rail transport, which simplifies delivery,” said Fischer. “A 60-Hz turbine also saves on the number of combustor cans needed—12 versus 16 compared to a 50-Hz machine.”
First sales order
Announced in mid-June 2010, Siemens Energy Inc. has received an order from Florida Power & Light Co. (FPL) for six 60-Hz, H-class gas turbine-generator packages. The SGT6-8000H gas turbines will be used to modernize FPL’s Riviera Beach and Cape Canaveral Next Generation Clean Energy Centers in Florida. They will help double the output of these power plants, while reducing CO2 emissions by 50%, according to Siemens.
Three SGT6-8000H turbines will go to each power plant, replacing outdated gas- and oil-fired units. Modernization work has begun at the Cape Canaveral plant and is expected to start in late 2010 at the Riviera plant, with return to service for these plants expected in 2013 and 2014, respectively.
Frank J. Bartos, PE, is a Control Engineering contributing content specialist. Reach him at firstname.lastname@example.org.
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