Siemens Energy’s SGT5-9000HL gas turbine, located at SSE’s Keadby-2 power station in the UK, is now the Guinness World Records title holder for the most efficient combined cycle power plant. The efficiency record of 64.2% was verified in May 2024,together with a second record as the most powerful combined cycle plant of almost 850 MW. In addition, with fast gas turbine ramping of 85 MW/minute, Keadby-2 provides important flexibility to complement non-dispatchable renewable generation. Construction of Keadby-2 began in August 2018 and it was officially handed over in March 2023. It has been calculated to contribute over £1b to the UK economy over its lifetime.

At the heart of the gas turbine is the advanced can-annular combustion system (ACE). This is a dry-low emissions system based on lean-premix technology which has been modified from earlier designs. This includes improved fuel mixing by increasing the number of premix burners per combustion can from 8 to 25, together with a reduction in residence time by shortening the burner transition pieces. This has allowed the gas turbine to achieve 25 ppmv NOx, which can be reduced further to 2 ppmv through the use of SCR, achievable down to 30% load.

The ACE combustion system can already handle 50% hydrogen fuel blends and Siemens claim that 100% hydrogen capability will be available by 2030.

As someone who worked on projects in the EU Framework-5 programme where 60% combined cycle efficiency was the ambitious target, to have now exceeded 64% only 20 years later is quite remarkable!