Supercritical steam generator

The water temperature drops below the critical point as it does work in a high pressure turbine and enters the generator's condenser, resulting in slightly less fuel use.

At supercritical pressure the higher temperature steam is converted more efficiently to mechanical energy in the turbine (as given by Carnot's theorem).

[1] In 1922, Mark Benson was granted a patent for a boiler designed to convert water into steam at high pressure.

In 1929, a test boiler that had been built in 1927 began operating in the thermal power plant at Gartenfeld in Berlin for the first time in subcritical mode with a fully open throttle valve.

[4] Two innovations have been projected to improve once-through steam generators[citation needed]: On 3 June 2014, the Australian government's research organization CSIRO announced that they had generated 'supercritical steam' at a pressure of 23.5 MPa (3,410 psi) and 570 °C (1,060 °F) in what it claims is a world record for solar thermal energy.

[5] These definitions regarding steam generation were found in a report on coal production in China investigated by the Center for American Progress.

[9][10] Industry leading (as of 2019) Mitsubishi Hitachi Power Systems charts its gas turbine combined cycle power generation efficiency (lower heating value) at well under 55% for gas turbine inlet temp of 1,250 °C (2,282 °F), roughly 56% for 1,400 °C (2,552 °F), about 58% for 1,500 °C (2,732 °F), and 64% for 1,600 °C (2,912 °F), all of which far exceed (due to Carnot efficiency) thresholds for AUSC or Ultra-supercritical technology, which are still limited by the steam temperature.