Siemens delivers first HL-class gas turbine

Siemens recently delivered the world’s first HL-class gas turbine, an SGT6-9000HL engine, to Duke Energy’s Lincoln Combustion Turbine Station near Denver, N.C., USA.

Workers lifted the 340 tonne turbine onto its foundation in November 2019, and the new unit is expected to start operating in early 2020. To validate the new HL-class technology, it first underwent component and prototype testing at Siemens’ facilities in Germany and the SGT6-9000HL will start a four-year testing process at Duke Energy’s station in 2020.

The unit will operate in simple-cycle mode under real power plant conditions, allowing Siemens to assess and modify its new technologies in real time and potentially achieve the next level of efficiency. Duke Energy customers will receive the unit’s 402 megawatts of energy during the four-year testing period while only paying some fuel costs. When testing is completed in 2024, Duke Energy will begin operating the unit, which will supply enough energy to power more than 300,000 homes in the Carolinas.

With a simple-cycle efficiency of 43%, the unit will be the most efficient of its type in Duke Energy’s fleet and about 34% more efficient than the existing combustion turbines at the Lincoln station. The new unit can also start quickly, giving Duke Energy more flexibility to support its growing portfolio of solar generation, helping the company to continue its plan to close older coal-fired units.

The Siemens HL-class turbine is built on four generations of technologies and five previous models, including the H-class, taking the best DNA from each of the previous models.

The proven engine architecture includes an air-cooled four-stage power turbine, hydraulic clearance optimization for higher efficiency at full load while facilitating immediate restart, a service-friendly steel rotor design employing Hirth serrations, a central single tie rod to lock discs and a can annular combustion system.

The gas turbine ramp-up rate of about 85 megawatts a minute maximizes operational flexibility. With increased inspection intervals of 33,000 equivalent base hours and 1,250 equivalent starts, the unit provides outstanding reliability.