I don’t think it makes sense to compare those efficiencies, as one is for converting heat to electricity, while the other is for converting sunlight. If you use sunlight to heat water and then use that for a steam turbine, the efficiency is similar to a photovoltaic panel.
The efficiency numbers are still useful, but only when they refer to the same starting point for the conversion (e.g. only comparing things that turn heat into electricity).
You are right it doesnt really makes sense to compare them that way, it was just what the initial comment was doing.
Nuclear fission is in itself only like 30% efficient.
There are of course tons of metrics to compare these things, I personally like space-time efficiency or CO2/MWh.
Yeah, it’s comparing apples to crabs. It’s only looking at the very final stage and ignoring the efficiencies of the fuel, etc.
If you wanted to make the comparison more fair (and also show how bad it is), a coal power plant maybe has an efficiency of 35%. You can calculate that by dividing the thermal energy in by the electric energy out. You feed in enough coal to generate 8MW of heat, which generates 2.8MW of electricity, so 2.8/8 = 0.35. By contrast, a photovoltaic power plant generates say 2kW of electricity with 0 fuel, so it has an efficiency of ∞%.
I don’t think it makes sense to compare those efficiencies, as one is for converting heat to electricity, while the other is for converting sunlight. If you use sunlight to heat water and then use that for a steam turbine, the efficiency is similar to a photovoltaic panel. The efficiency numbers are still useful, but only when they refer to the same starting point for the conversion (e.g. only comparing things that turn heat into electricity).
You are right it doesnt really makes sense to compare them that way, it was just what the initial comment was doing. Nuclear fission is in itself only like 30% efficient. There are of course tons of metrics to compare these things, I personally like space-time efficiency or CO2/MWh.
Yeah, it’s comparing apples to crabs. It’s only looking at the very final stage and ignoring the efficiencies of the fuel, etc.
If you wanted to make the comparison more fair (and also show how bad it is), a coal power plant maybe has an efficiency of 35%. You can calculate that by dividing the thermal energy in by the electric energy out. You feed in enough coal to generate 8MW of heat, which generates 2.8MW of electricity, so 2.8/8 = 0.35. By contrast, a photovoltaic power plant generates say 2kW of electricity with 0 fuel, so it has an efficiency of ∞%.