this post was submitted on 02 Mar 2024
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[–] [email protected] 44 points 8 months ago* (last edited 8 months ago) (5 children)

I often hear people saying "But where does the electricity for the EV come from? Driving an EV is not better than driving a diesel."

They have to realize that the thiny ICE in your car is optimised for weight, and has an efficiency of 30-35%. So about ⅔ of the fossil fuel is turned into heat and blown out of the exhaust. Compare that to the turbine in a coal or gas plant, which can archive up to 90% efficiency.

And don't forget that an EV is an investment, which will likely still be on the road in 20 years time. The electricity mix at the moment is still rather fossil fuel heavy, but this will change completely within the next 10 years.

Edit: not 90% but 40% efficiency. See comments below

[–] [email protected] 19 points 8 months ago (2 children)

Compare that to the turbine in a coal or gas plant, which can archive up to 90% efficiency.

Nope, you might have seen 90+% efficiency when talking about steam power plants, but that's the efficiency of the generator(converting the mechanical energy of the the rotating turbogenerator to electricity). You have to multiply with the efficiency of the turbine(converting the energy of the heated gases into the mechanical energy) and there the efficiency is much lower, ~40% for a coal fired and maybe <60% for a gas combined cycle.

[–] [email protected] 18 points 8 months ago

Yeah. Power plants are nowhere near 90% efficient.

It's worth emphasizing, though, that they're still way, way more efficient than car engines are.

Also, regenerative breaking saves a lot of energy. Basically, instead of using the motor to increase the cars speed, you use it as a generator to recharge the battery.

[–] [email protected] 6 points 8 months ago

Huh, that makes a lot of sense actually. Thanks for correcting!

[–] [email protected] 14 points 8 months ago

Not to mention that a grid doesn't have to be a coal or gas plant. Lots of houses have solar charging now, for example.

[–] [email protected] 6 points 8 months ago (1 children)

Last time I looked (a few years ago), a 100% coal powered EV had similar emissions to a 60mpg car.

I doubt anywhere will still be coal powered in a decade, with how fast plants are closing. But that EV will still be there on its 3rd owner.

[–] [email protected] 7 points 8 months ago* (last edited 8 months ago) (1 children)

Different countries and states obviously have different electricity source mixes.

Here in the UK, coal accounts for around 1% of electricity. Natural gas is about 35%, biomass about 5%, and the rest is various clean renewables (wind, solar, hydro) or nuclear.

So although charging an EV is by no means fossil-fuel-free, it's considerably less fossil-fuel than an ICE car.

[–] [email protected] 3 points 8 months ago

So although charging an EV is by no means fossil-fuel-free, it’s considerably less fossil-fuel than an ICE car.

That was my point. Even in the worst case it's comparable to 60mpg.... No ICE gets 60mpg. And in a decade it'll be even better.

[–] [email protected] -5 points 8 months ago (1 children)

We need a professional copy editor on this comment.

[–] [email protected] 2 points 8 months ago (1 children)
[–] [email protected] 1 points 8 months ago* (last edited 8 months ago)

The Thiny ICE? Also, your archiving is 90% efficient?