4 ms·

> It's more efficient to power your car with oil directly than to burn the oil for electricity and then power your car with that. Please run numbers and you ma

by llukas 7y ago

> It's more efficient to power your car with oil directly than to burn the oil for electricity and then power your car with that. Please run numbers and you may be surprised.

ascar 7y ago
I was actually surprised by most sources I found online. But all top hits on Google start off at the charger and ignore any efficiency losses for generating the electricity in the first place. Some even acknowledge that fact in text, but still avoid calculations. If we go from 46.4 MJ/kg energy in 1 liter of gasoline and apply the usual density of about 0.75kg/l, that's 34.8MJ/kg. At 3.6 MJ per kwH that's ~9.7kwH/l. A modern car uses about 6l gasoline per 100km, so 60kwH per 100km. A Tesla Model S uses about 20kwH per 100km. So a modern ICE car is about 1/3 as efficient as a Tesla Model S. But if we go from my argument, that we currently still burn oil to provide more electricity and adding more energy consumers to the network only delays the reduction of burning fossil fuels for electricity, we need to take into account the efficiency of fossil power plants. An oil power plant runs at about 45% efficiency. Lets ignore transport and charging losses, as transporting gasoline isn't exactly free either. That takes the Tesla up to 45 kwH/100km. So that's actually still a 25% efficiency gain towards the ICE car, which I didn't expect. To get the full picture however, we would have to add the 65.000kwH of energy used to build a 100kwH battery pack (upscaled based on [1]). A (estimated) 10kg steel gasoline tank takes maybe 200kwH of energy to manufacture (based on 50GJ/1000kg of steel and some adds for other stuff that needs to be done). Even if I'm off by an order of magnitude on the steel tank, that's still an energy difference worth north of 100.000km (i.e. more than most cars travel in their lifetime or another at least 50% effiency loss for the EV). I still wonder if the 25% efficiency gain outweights the cost of the battery production and the cost of adding a large scale charging network to support the broad adoption of electricle vehicles. Or, to rephrase my original argument, if we are better off taking the additional ~50% efficiency loss in converting energy to fuels and focus on expanding our carbon neutral energy production, shutting of fossil power plants and investing more in fusion energy so that might become a reality and we can create an abundance of energy to work with. [1] https://www.researchgate.net/publication/316884465_Manufacturing_energy_analysis_of_lithium_ion_battery_pack_for_electric_vehicles https://www.researchgate.net/publication/316884465_Manufactu...
- llukas 7y ago
  Tesla Model 3 is roughly 15kwh per 100km. See this [1] for discussion of gasoline production - even more unexpected and complicated to tally. We are already getting EV emitting less CO2 each year, see here [2]. With wind/solar (+batteries) getting even more wins over coal due to price drops, this process will only accelerate — no need to wait for fusion. [1] https://greentransportation.info/energy-transportation/gasoline-costs-6kwh.html https://greentransportation.info/energy-transportation/gasol... [2] https://blog.ucsusa.org/dave-reichmuth/new-data-show-electric-vehicles-continue-to-get-cleaner https://blog.ucsusa.org/dave-reichmuth/new-data-show-electri...
- adrianN 7y ago
  The good part is that electric cars automatically "produce" less CO2 as we replace fossil fuels on the grid. Most cars are around for more than ten years, but to reach climate goals we need to cut fossil fuel use quickly quickly. At least 50% reduction in all fossil fuels till 2030. Electricity is much easier to replace than, e.g., heating so hopefully the electric grid will lead the change.

by llukas 7y ago

> It's more efficient to power your car with oil directly than to burn the oil for electricity and then power your car with that. Please run numbers and you may be surprised.

ascar 7y ago

I was actually surprised by most sources I found online. But all top hits on Google start off at the charger and ignore any efficiency losses for generating the electricity in the first place. Some even acknowledge that fact in text, but still avoid calculations. If we go from 46.4 MJ/kg energy in 1 liter of gasoline and apply the usual density of about 0.75kg/l, that's 34.8MJ/kg. At 3.6 MJ per kwH that's ~9.7kwH/l. A modern car uses about 6l gasoline per 100km, so 60kwH per 100km. A Tesla Model S uses about 20kwH per 100km. So a modern ICE car is about 1/3 as efficient as a Tesla Model S. But if we go from my argument, that we currently still burn oil to provide more electricity and adding more energy consumers to the network only delays the reduction of burning fossil fuels for electricity, we need to take into account the efficiency of fossil power plants. An oil power plant runs at about 45% efficiency. Lets ignore transport and charging losses, as transporting gasoline isn't exactly free either. That takes the Tesla up to 45 kwH/100km. So that's actually still a 25% efficiency gain towards the ICE car, which I didn't expect. To get the full picture however, we would have to add the 65.000kwH of energy used to build a 100kwH battery pack (upscaled based on [1]). A (estimated) 10kg steel gasoline tank takes maybe 200kwH of energy to manufacture (based on 50GJ/1000kg of steel and some adds for other stuff that needs to be done). Even if I'm off by an order of magnitude on the steel tank, that's still an energy difference worth north of 100.000km (i.e. more than most cars travel in their lifetime or another at least 50% effiency loss for the EV). I still wonder if the 25% efficiency gain outweights the cost of the battery production and the cost of adding a large scale charging network to support the broad adoption of electricle vehicles. Or, to rephrase my original argument, if we are better off taking the additional ~50% efficiency loss in converting energy to fuels and focus on expanding our carbon neutral energy production, shutting of fossil power plants and investing more in fusion energy so that might become a reality and we can create an abundance of energy to work with. [1] https://www.researchgate.net/publication/316884465_Manufacturing_energy_analysis_of_lithium_ion_battery_pack_for_electric_vehicles https://www.researchgate.net/publication/316884465_Manufactu...

llukas 7y ago
Tesla Model 3 is roughly 15kwh per 100km. See this [1] for discussion of gasoline production - even more unexpected and complicated to tally. We are already getting EV emitting less CO2 each year, see here [2]. With wind/solar (+batteries) getting even more wins over coal due to price drops, this process will only accelerate — no need to wait for fusion. [1] https://greentransportation.info/energy-transportation/gasoline-costs-6kwh.html https://greentransportation.info/energy-transportation/gasol... [2] https://blog.ucsusa.org/dave-reichmuth/new-data-show-electric-vehicles-continue-to-get-cleaner https://blog.ucsusa.org/dave-reichmuth/new-data-show-electri...
adrianN 7y ago
The good part is that electric cars automatically "produce" less CO2 as we replace fossil fuels on the grid. Most cars are around for more than ten years, but to reach climate goals we need to cut fossil fuel use quickly quickly. At least 50% reduction in all fossil fuels till 2030. Electricity is much easier to replace than, e.g., heating so hopefully the electric grid will lead the change.