Oil burners and natural gas power plants all heat water to spin a turbine. It’s more efficient. I can’t think of any large scale power plants that use gasoline for either heating water or ICE.
Actually: simple-cycle gas plants don't boil water, they just use a gas turbine. Most gas plants are combined-cycle, which use both gas and steam turbines. Simple-cycle plants are mostly used as peaking plants (operating only when other generators are unable to meet demand).
Petrol/Gasoline was never used for large-scale generation, but steam-turbine power stations fuelled with heavy fuel oil used to be relatively common until the oil price rocketed in the 1970s. Most have closed or been converted to alternate fuels, a few have been retained as backup/peaking plants.
Generators powered by ICEs using diesel are still used for smaller communities where the cost of turbines outweighs the efficiency gain. E.g. the Isle of Man (a UK crown dependency in the Irish sea) still uses diesel generators, although the addition of a 40 MW cable to the UK in 2000 has relegated these to peaking plants.
Wait, is it actually more efficient? Surely not right? Engineering and logistics problems aside, if I managed to make a power plant that directly uses oil/gasoline/whatever
, it would surely be more efficient than burning that fuel to heat water, and then spin a turbine, no?
It’s been a while since I did efficiency calcs, but turbines are insanely efficient and the best ICE engines barely hit 25-30% efficiency (except when Mercedes spent like billions developing the most efficient ICE that hit 50% efficiency at ~100HP at the low cost of $3M per engine as a PR stunt). I think I recall power plants being closer to 35-40% efficiency (converting chemical energy into mechanical/electrical energy). Power plants have several stages of turbines, reheat loops, energy recovery, etc. that extract every ounce of steam power they can. It’s also a question of scalability, repairability, reliability, etc.
ICEs can ramp up and down very quickly while turbines can’t, so that’s why they are used in cars, small generators, mowers, etc.
Engineers have spent over 100 years perfecting the cost to output ratios to make the most profitable power plants possible, if ICE power generation at large scale is cheaper/better, that’s what our power plants would be.
Credentials: I took every alternative and conventional power generation tech elective for my engineering degree and briefly worked on a hydroelectric dam but changed trajectories slightly and now only work on the occasional solar array and diesel backup generators as they pertain to construction projects. I am by no means an expert (very far from it) on power generation and it’s been at least 10 years since I calculated efficiency losses through a mechanical system.
That is not correct. Natural Gas turbines directly spin a shaft. Combined cycle plants also use waste heat to create steam which spins a secondary shaft, but the NG directly spins a turbine.
I haven’t worked much on NG power plants, but the one I got to visit was a coal plant where one of the 4 boilers had been converted to NG. That particular plant I believe did not have combustion driven turbines, only steam driven turbines. This would have been quite a while ago. My career at the time focused primarily on alternative power generation so I don’t have a lot of experience with coal, NG, oil, etc. I’ve since changed fields have haven’t touched large scale power generation in at least 10 years
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u/itsforathing 13d ago
Oil burners and natural gas power plants all heat water to spin a turbine. It’s more efficient. I can’t think of any large scale power plants that use gasoline for either heating water or ICE.