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EVs can be better even if they're powered by coal: https://www.forbes.com/sites/mikescott/2020/03/30/yes-electric-cars-are-cleaner-even-when-the-power-comes-fr

by api 6y ago

EVs can be better even if they're powered by coal: https://www.forbes.com/sites/mikescott/2020/03/30/yes-electric-cars-are-cleaner-even-when-the-power-comes-from-coal/?sh=4d8069412320 https://www.forbes.com/sites/mikescott/2020/03/30/yes-electr... There are numerous reasons for this. One is that oil drilling, shipping, and refining is dirty and uses a ton of energy. Another is that large heat engines are often many times more efficient than small ones. A huge 100+ megawatt steam turbine at a coal plant is going to have 2-3X the thermal efficiency of a small ICE in a car, especially if it's a newer or recently upgraded supercritical steam system. I recall reading that CO2/mile for a coal powered EV is typically similar to driving a high efficiency hybrid gasoline car like a Prius, but I can't find the reference right now.

qwytw 6y ago
"I recall reading that CO2/mile for a coal powered EV is typically similar to driving a high efficiency hybrid gasoline car like a Prius, but I can't find the reference right now." No, that's not even close to being correct, the most efficient Prius model you can currently buy supposedly only emits 75g per km. Tesla Model 3 consumes 14.9 kWh per 100 km, coal plants in the US on average emit ~1kg of CO2 per kWh. The energy loss between the power plant and consumer seems to be between 8 and 15%. So using 8% it's 160g of CO2 per km. I'm not sure if the data reported by Tesla accounts for charger efficiency (which is at maximum 92% and might be as low as 70-80% if you're charging at home) if not that would at least another 8% making it 173g per km or more. Even a very efficient petrol car like for example WV Golf Rr 1.5 TSI is quite a bit lower than that at 116g per km. https://www.eia.gov/tools/faqs/faq.php?id=74&t=11 https://www.eia.gov/tools/faqs/faq.php?id=74&t=11 Switching to Natural gas would decrease CO2 per kWH more than twice, from 1kg to 0.41 kg per kWh would make Model 3 about even with the Prius (71 vs 75 g per km).
- api 6y ago
  Does this count all the energy required to drill, ship, and refine oil? I’ve read that refineries use a ton of power usually in the form of gas, electricity, or burning part of the oil. Coal is mined too but it doesn’t require much processing.

by api 6y ago

qwytw 6y ago

"I recall reading that CO2/mile for a coal powered EV is typically similar to driving a high efficiency hybrid gasoline car like a Prius, but I can't find the reference right now." No, that's not even close to being correct, the most efficient Prius model you can currently buy supposedly only emits 75g per km. Tesla Model 3 consumes 14.9 kWh per 100 km, coal plants in the US on average emit ~1kg of CO2 per kWh. The energy loss between the power plant and consumer seems to be between 8 and 15%. So using 8% it's 160g of CO2 per km. I'm not sure if the data reported by Tesla accounts for charger efficiency (which is at maximum 92% and might be as low as 70-80% if you're charging at home) if not that would at least another 8% making it 173g per km or more. Even a very efficient petrol car like for example WV Golf Rr 1.5 TSI is quite a bit lower than that at 116g per km. https://www.eia.gov/tools/faqs/faq.php?id=74&t=11 https://www.eia.gov/tools/faqs/faq.php?id=74&t=11 Switching to Natural gas would decrease CO2 per kWH more than twice, from 1kg to 0.41 kg per kWh would make Model 3 about even with the Prius (71 vs 75 g per km).

api 6y ago
Does this count all the energy required to drill, ship, and refine oil? I’ve read that refineries use a ton of power usually in the form of gas, electricity, or burning part of the oil. Coal is mined too but it doesn’t require much processing.