5 ms·

Electric cars are usually about 4x as efficient as ICE in terms of energy input -> propulsive energy[1], so it's more like $5.50/gallon, but still pretty expens

Electric cars are usually about 4x as efficient as ICE in terms of energy input -> propulsive energy[1], so it's more like $5.50/gallon, but still pretty expensive. [1] http://www.afteroilev.com/Pub/EFF_Tank_to_Wheel.pdf http://www.afteroilev.com/Pub/EFF_Tank_to_Wheel.pdf

clysm 4y ago
While EVs are much more efficient, you don't factor in vehicle efficiency when calculating $/eGallon. $20/eGallon is huge. My cost at home to charge is $4.10/eGallon, regardless of the efficiency of the car using it.
- cameldrv 4y ago
  Sure. However, IMO it's more useful to look at it from this standpoint: Most usage of energy has to go through a thermal->mechanical energy conversion step. Carnot efficiency practically limits this to 20-60% efficiency or so. In general, the smaller the engine, the worse the efficiency. If your energy input is electricity, this conversion has already happened at the power plant. If your energy input is gasoline, it happens in the car. It's sort of like comparing your salary pre-tax vs. post-tax if the tax rate is 70%. There's a big difference. Most of the other energy conversions like electrical->mechanical, mechanical->electrical, electrical->battery or battery->electrical can be done at 90%+ efficiency.
rektide 4y ago
I pity the consumer that ignores how efficient their vehicle is to justify paying 3x as much for energy. I think this is intensely backwards & wrong a way to look at it. In my view, all EV chargers should be mandated to express a $/"gallon" equivalent on them. So consumers know the real actual physical reality truth of the situation. Hiding this, making EV buyers unaware of their own efficiency, is making the market blind. The market should be aware of the truth. Edit: your EV should also make it clear that it has 2-3 gallons of capacity. Because it's awesome & the future & we should all do it. But that doesn't change the fact that the dude in the F250 over there is paying 1/4th as much for the same energy you're getting, and that matters and should be seen.

clysm 4y ago

While EVs are much more efficient, you don't factor in vehicle efficiency when calculating $/eGallon. $20/eGallon is huge. My cost at home to charge is $4.10/eGallon, regardless of the efficiency of the car using it.

cameldrv 4y ago
Sure. However, IMO it's more useful to look at it from this standpoint: Most usage of energy has to go through a thermal->mechanical energy conversion step. Carnot efficiency practically limits this to 20-60% efficiency or so. In general, the smaller the engine, the worse the efficiency. If your energy input is electricity, this conversion has already happened at the power plant. If your energy input is gasoline, it happens in the car. It's sort of like comparing your salary pre-tax vs. post-tax if the tax rate is 70%. There's a big difference. Most of the other energy conversions like electrical->mechanical, mechanical->electrical, electrical->battery or battery->electrical can be done at 90%+ efficiency.

rektide 4y ago

I pity the consumer that ignores how efficient their vehicle is to justify paying 3x as much for energy. I think this is intensely backwards & wrong a way to look at it. In my view, all EV chargers should be mandated to express a $/"gallon" equivalent on them. So consumers know the real actual physical reality truth of the situation. Hiding this, making EV buyers unaware of their own efficiency, is making the market blind. The market should be aware of the truth. Edit: your EV should also make it clear that it has 2-3 gallons of capacity. Because it's awesome & the future & we should all do it. But that doesn't change the fact that the dude in the F250 over there is paying 1/4th as much for the same energy you're getting, and that matters and should be seen.