4 ms·

You are forgetting that you still have to create the electricity. So you have to multiply with the thermal efficiency of the electricity generation (if it uses

You are forgetting that you still have to create the electricity. So you have to multiply with the thermal efficiency of the electricity generation (if it uses fossil fuels). The TEs for car motors and gas turbine electricity generation are roughly the same (0.4). So the electric motor has to have an efficiency of 1 (read 0 losses) to not be less efficient overall. So, no, just electrifying is not more efficient. We need a sustainable, renewable energy source like solar.

bryanlarsen 4y ago
Almost all new electricity generation is renewable. Nameplate capacity installation is only about 66% renewable, but the the actual generation of electricity by natgas plants is switching from continuous to intermittent peaking, so that balances out. Regardless your original thesis is also wrong, since a gasoline engine is 20-40% efficient and a combined cycle gas turbine is 50-60%+ efficient. If you measure by carbon emissions, it's even more stark. A gasoline car emits more than twice as much carbon as an electric car running on natgas generated electricity.
deleted 4y ago
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Szpadel 4y ago
not really, keep in mind that electric cars are able to recover energy from breaking, while traditional convert that to waste heat, that should tip average efficiency by dozen of percent points. That's also from where mild hybrids have better efficiency. for heating heat pumps have it's average yearly efficiency about 300-500% (depending on climate) so when we use the same fuel to just make energy at with that 40% you mentioned, we end up with overall efficiency well over 100% so in both cases it's better to burn the same fuel to create electricity than to use it directly
idontwantthis 4y ago
A heat pump powered by natural gas generated electricity is still more efficient than burning the natural gas where the heat is needed.

bryanlarsen 4y ago

Almost all new electricity generation is renewable. Nameplate capacity installation is only about 66% renewable, but the the actual generation of electricity by natgas plants is switching from continuous to intermittent peaking, so that balances out. Regardless your original thesis is also wrong, since a gasoline engine is 20-40% efficient and a combined cycle gas turbine is 50-60%+ efficient. If you measure by carbon emissions, it's even more stark. A gasoline car emits more than twice as much carbon as an electric car running on natgas generated electricity.

deleted 4y ago

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Szpadel 4y ago

not really, keep in mind that electric cars are able to recover energy from breaking, while traditional convert that to waste heat, that should tip average efficiency by dozen of percent points. That's also from where mild hybrids have better efficiency. for heating heat pumps have it's average yearly efficiency about 300-500% (depending on climate) so when we use the same fuel to just make energy at with that 40% you mentioned, we end up with overall efficiency well over 100% so in both cases it's better to burn the same fuel to create electricity than to use it directly

idontwantthis 4y ago

A heat pump powered by natural gas generated electricity is still more efficient than burning the natural gas where the heat is needed.