Sure Dieter, all heat engine cycles are not very efficient. PV and wind are not heat engine cycles. The nuclear boys harp on their low CO2, but they contribute directly to global warming through heat - that's why they build the reactors next to large bodies of water. They dismiss and trivialize their radionuclide emissions while quietly researching their accumulating effects. Like I said, nuclear is not a long term solution. By the way, solar panel energy efficiency
is very low.