The upgrade offers up to a 3.5 percent increase of simple cycle gas turbine efficiency and up to an additional 10 megawatt (MW) output, enhancing the power of 43-47.5 MW units up to 53 MW. For combined cycle applications, the enhancement could result in a power increase of more than 20 MW and a 3.5 percent lower heat rate, based on a combined cycle 2xSGT-800 and one steam turbine. The heat rate improvement contributes to both fuel savings and CO2 emission reductions.
Siemens evolutionary upgrades are based on operating experience and OEM optimized design. This upgrade is infusing the components included in the later versions of the SGT-800 (50.5-54 MW). In this case, an improved compressor blade design is included for increased aerodynamic performance. Optimized gas path mass flow and component cooling in the turbine section are also included. The combined upgrades are designed to produce only a moderate increase in combustion chamber firing temperature. The upgrade is preferably installed in conjunction with a scheduled major overhaul. As it uses features from existing and proven SGT-800s with higher ratings, upgrade customers benefit from a proven and reliable technology.
With its robust portfolio of digital service solutions, Siemens is also recommending a move from the more traditional fixed-interval maintenance based on Equivalent Operating Hours (EOH) to tailored maintenance plans in conjunction with this upgrade. A FlexLTP with a tailored maintenance plan gives users access to specific OEM knowledge and advanced optimization technologies that can also support extended time between overhauls.
To date, more than 350 SGT-800 turbines have been sold worldwide. Over the last six years the SGT-800 has been the market-leading gas turbine for combined cycle applications in its power range. The installed SGT-800 fleet has currently reached more than six million operating hours and the fleet average reliability for 2017 was 99.7 percent (GT package). In 2017, the latest upgrade to the new unit SGT-800 was announced offering an output of 57 MW and an electrical efficiency of more than 40 percent in simple cycle application. In a combined cycle configuration, with 2xSGT-800 and one steam turbine, the power output of the new unit is 163 MW at a net efficiency of 58.6 percent. The turbine, which was originally known under the product name GTX100, began development in 1994 and was introduced to the market in 1998.