That is not great compared with the 20% and more achieved by a silicon-based solar cell, the 40% managed by a solar-thermal turbine, or even the 18-20% of one of the new generation of cheap and cheerful thin-film solar cells.

ECONOMIST: Solar power

It is the thermal energy of the gas, after all, that the turbine converts into electricity, so the colder the gas, the lower the yield.

ECONOMIST: Geothermal energy: Blowing hot and cold | The

As solar panel prices have plunged, developers like Solar Millennium have abandoned solar thermal technology, which uses huge mirror arrays to heat water to create steam that drives an electricity-generating turbine.

FORBES: U.S. Solar Market Jumps 69% in Q2 But Likely To Cool Off