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Aren’t most power grids still powered mostly by fossil fuels. You have to pay for the fuel one way or another - i.e. if it’s not gasoline, it’s coal or natural

Aren’t most power grids still powered mostly by fossil fuels. You have to pay for the fuel one way or another - i.e. if it’s not gasoline, it’s coal or natural gas; unless you charge only at peak solar/wind power generation and there is excess power generated, your charging will increase fossil fuel usage.

ajuc 5y ago
ICE have <30% efficiency. Usually about 20%. Turbines in powerplants have about 50% efficiency. Best ones up to 60%. Even if you get all your energy from fossil fuels it's better to burn them in powerplants than in small inefficient ICEs in cars that most of the time aren't even working in optimal conditions and start/stop constantly.
- worrycue 5y ago
  I suppose my point is you are still burning fossil fuels - admittedly less of it - in most cases (for now) so you pay into the shipping of that stuff around too.
  - ajuc 5y ago
    Well, yes, but you need half the tankers, half the pipelines, half the refineries, etc.
- beerandt 5y ago
  Once you account for transmission, distribution, charging, and battery inefficiencies, electrics fall to the same range or below ice vehicles. Especially using fast charging technology. And ironically, using grid renewables decreases relative efficiency, since they require more deployed infrastructure (collection, transmission, etc) per kilowatt-hour generated, since intermittency has to be factored in, as well as the embedded cost of whatever supplies power when the sun isn't shining and wind isn't blowing, whether that be hydro, batteries, natural gas peakers, or nuclear.
  - rektide 5y ago
    EIA estimates 5% grid loss. Charge cycles should be >85% efficient i'd hope (battery losses & charger losses) but probably not in all vehicles. Discharge I'd expect even better. Your guestimate sounds way way off to me. I'd also expect significant improvement over time. We're just getting good at GaN fets & SiC fets, which usually have a couple % boost to efficiencies versus classic semiconductor chemistries. Newer lower internal resistance batteries provide more power on demand and heat up less, again boosting efficiency. Where-as with cars we've had a number of historical events pushing us towards efficiency, huge incentives to make trucking or other major industries more efficienct, and yet we've seen dwindling returns on optimization investment: we're already very good at gas. Short of jumping to turbines or other radical leaps. You also havent accounted for energy costs to store, transport/distribute gas, in spite of holding that against electric vehicles. I expect that's probably >15% efficiency loss there too for gas. We could go deeper & assess the energy inputs required to produce these units of power, a gallon of refined low sulfur highway gas versus the kWh produced by solar, nuclear, natural gas, or, heaven forbid coal at the power plant. Again i feel like gas is rapidly losing efficiency marks versus the competiton. Off the cuff I'd expect >3x energy efficiency net.
RobAley 5y ago
Indeed, but even centralised coal fired electric generation produces less carbon per mile travelled than petrol/diesel engines. We're not there yet, but proper grid management and diverse renewable sources mean that an increasing number of countries are heading towards large parts of base load being renewable. In all scenarios (apart from not travelling at all) electric cars are a carbon win, and it looks like it will only increase.
stefan_ 5y ago
You can burn the gasoline in a central power station for electricity, feed that into the grid, charge your electric car and still go further than the same amount of gasoline in a petrol car. Without all the adverse health issues that exhaust in close vicinity to people causes.

ajuc 5y ago

ICE have <30% efficiency. Usually about 20%. Turbines in powerplants have about 50% efficiency. Best ones up to 60%. Even if you get all your energy from fossil fuels it's better to burn them in powerplants than in small inefficient ICEs in cars that most of the time aren't even working in optimal conditions and start/stop constantly.

worrycue 5y ago
I suppose my point is you are still burning fossil fuels - admittedly less of it - in most cases (for now) so you pay into the shipping of that stuff around too.
- ajuc 5y ago
  Well, yes, but you need half the tankers, half the pipelines, half the refineries, etc.
beerandt 5y ago
Once you account for transmission, distribution, charging, and battery inefficiencies, electrics fall to the same range or below ice vehicles. Especially using fast charging technology. And ironically, using grid renewables decreases relative efficiency, since they require more deployed infrastructure (collection, transmission, etc) per kilowatt-hour generated, since intermittency has to be factored in, as well as the embedded cost of whatever supplies power when the sun isn't shining and wind isn't blowing, whether that be hydro, batteries, natural gas peakers, or nuclear.
- rektide 5y ago
  EIA estimates 5% grid loss. Charge cycles should be >85% efficient i'd hope (battery losses & charger losses) but probably not in all vehicles. Discharge I'd expect even better. Your guestimate sounds way way off to me. I'd also expect significant improvement over time. We're just getting good at GaN fets & SiC fets, which usually have a couple % boost to efficiencies versus classic semiconductor chemistries. Newer lower internal resistance batteries provide more power on demand and heat up less, again boosting efficiency. Where-as with cars we've had a number of historical events pushing us towards efficiency, huge incentives to make trucking or other major industries more efficienct, and yet we've seen dwindling returns on optimization investment: we're already very good at gas. Short of jumping to turbines or other radical leaps. You also havent accounted for energy costs to store, transport/distribute gas, in spite of holding that against electric vehicles. I expect that's probably >15% efficiency loss there too for gas. We could go deeper & assess the energy inputs required to produce these units of power, a gallon of refined low sulfur highway gas versus the kWh produced by solar, nuclear, natural gas, or, heaven forbid coal at the power plant. Again i feel like gas is rapidly losing efficiency marks versus the competiton. Off the cuff I'd expect >3x energy efficiency net.

RobAley 5y ago

Indeed, but even centralised coal fired electric generation produces less carbon per mile travelled than petrol/diesel engines. We're not there yet, but proper grid management and diverse renewable sources mean that an increasing number of countries are heading towards large parts of base load being renewable. In all scenarios (apart from not travelling at all) electric cars are a carbon win, and it looks like it will only increase.

stefan_ 5y ago

You can burn the gasoline in a central power station for electricity, feed that into the grid, charge your electric car and still go further than the same amount of gasoline in a petrol car. Without all the adverse health issues that exhaust in close vicinity to people causes.