Siemens launches performance enhancement offering for SGT-800

Siemens is offering a new SGT-800 performance upgrade, applicable to existing SGT-800 machines with the 43-47.5-MW ratings. The new upgrade offers up to a 3.5% increase in simple cycle gas turbine efficiency and up to an additional 10 MW of output when applied to the 43 MW engines. In combined cycle applications, the upgrade could result in an additional plant output of 20 MW and a 3.5% lower heat rate, based on 2 x SGT-800 and one steam turbine. The timing is interesting as GE has recently announced it is offering SGT-800 upgrades as part of its new Cross-Fleet initiative, see MPS, July 2018, pp12-16, 'Next steps for GE services: Cross-Fleet and AGP expansion'.

Siemens says its “evolutionary” upgrades are based on operating experience and “OEM optimised design...infusing the components included in the later versions of the SGT-800” (50.5-54 MW).

The upgrade includes an improved compressor blade design, achieving increased aerodynamic performance. Optimised gas path mass flow and component cooling in the turbine section are also included, says Siemens, but “the combined upgrades are designed to produce only a moderate increase in combustion chamber firing temperature.”

Siemens suggests that the upgrade is best installed in conjunction with a scheduled major overhaul.

Based on its digital service offerings, Siemens is also recommending, in conjunction with this upgrade, a move from traditional fixed-interval maintenance based on equivalent operating hours (EOH) to tailored maintenance plans. “A FlexLTP with a tailored maintenance plan gives users access to specific OEM knowledge and advanced optimisation technologies that can also support extended time between overhauls”, says Siemens.

To date, Siemens reports, more than 350 SGT-800 turbines have been sold worldwide and the fleet has amassed more than six million operating hours, with a fleet average reliability in 2017 of 99.7%.

In 2017, the latest upgrade to the SGT-800 was announced, taking the rated output to 57 MW with an electrical efficiency of more than 40% in simple cycle. In combined cycle, with two of the uprated SGT- 800 units and one steam turbine, the total power output is 163 MW and net efficiency is 58.6%. The turbine, originally known under the product name GTX100, began development in 1994 and was introduced to the market in 1998.

• Panama order. Meanwhile, Siemens has reported its first SGT-800 order from Panama. This is for six SGT-800 gas turbines, which, in conjunction with an SST-600 steam turbine, will provide 440 MW of flexible combined cycle power.

Siemens’ customer is Shanghai Electric Group, which is responsible for building the overall plant. The end customer is the independent power producer Martano, Inc. Commissioning for the power block is scheduled for autumn 2020.

As well as the gas turbines, which will be provided in “single lift” packages (see picture, left), and the steam turbine, Siemens’ scope also includes an SGen6-100A-2P steam turbine generator, six vertical once through HRSGs (VOTSG), as well as a Simatic PCS7 control system for the gas turbines and a SPPA-T3000 control system for the steam turbine.

The plant site is near the sea port of Colón on the Caribbean coast and the fuel will be LNG. Thanks to high efficiency in partial load operation and a high degree of operating flexibility, the new combined cycle power plant will be an ideal complement to fluctuating renewables, thus supporting the Panama government’s plans to expand wind and solar and to increase the share of renewables in the country’s energy mix to 70%.