The secret behind the latest generation of high-efficiency turbines is in the firing temperature. H-Class turbines have much higher firing temperatures than the temperatures used in F-Class or E-Class turbines.
The physics involved are complex, but a reasonable simplification is that efficiency shows a direct correlation to firing temperature. In some cases, high firing temperatures cannot be withstood by the materials used to make the turbines.
Manufacturers therefore have had to resort to special cooling techniques: air cooling in the most advanced models, ceramic coatings on the most vulnerable components, and careful management of combustion zones and where the flame sits.
The effort is worth it. Higher efficiency brings many benefits: lower fuel costs, lower capital expenditure, lower maintenance costs, and—crucially, in an age of escalating climate concerns—lower carbon dioxide emissions per unit of electricity generated.
More than ever, with the introduction of these high-efficiency turbines, gas-fired power stations are complementing renewables, rather than competing with them.