3 ms·

I cannot comment on the US numbers, but the German numbers are as following: - total electricity production is around 600 TWh/year - switching all cars to elect

by _ph_ 8y ago

I cannot comment on the US numbers, but the German numbers are as following: - total electricity production is around 600 TWh/year - switching all cars to electricity would require about 120 TWh/year (44M cars x 14000km/year * 20kWh/100km) That would be a 20% increase in electricity production required, but from that one can deduct quite a bit for fuel refining and distribution, better buffering of peak electricity production etc. If you take the energy content of fuel, an electric car is roughly 4x as efficient as a combustion engine. While combustion engines may reach peak efficiencies of 40%, the average over the whole driving cycle is less than 20%, as the peak efficiency is only reached in a narrow band of power productions - usually at highway speeds. That is the reason hybrid cars save fuel, the electric component reduces the inefficiencies of certain parts of the driving cycle.

reitzensteinm 8y ago
I'm not surprised the German numbers are better. But even there, with Germany's remarkable progress, a Tesla bought today will be scrapped before Germany reaches 120% of today's electrical production in renewables. Fair enough; I should have used 25% instead of 50%. In my head I was multiplying by the energy efficiency of electrical production but that of course is not relevant to this calculation. The irony of correcting a bad argument with a bad argument while complaining about the same is not lost on me. I believe my point stands.
- _ph_ 8y ago
  In Germany, far more reneweable power is added to the grid as the consumption could increase. With about 44 million cars on the road, every year 3 million new cars are sold, so it would take 15 years to add that extra 10-15% of electricity consumption to the grid. Whether the grid reaches 100% reneweable during the lifetime of an electric car bought today or not might not be clear, but the point being was, it is guaranteed to contain way more reneweables as of today and with that the base of the calculations was wrong.
  - reitzensteinm 8y ago
    If you're adding marginal consumption to the grid that does not exist today, you can't account for it as being in part powered by renewables. You are producing no more renewable energy than previously, and fossil fuel consumption will increase by exactly the amount you're adding to the grid. I'm not arguing that EVs aren't a good idea. I'm just in favor of being clear about the choice that's being made; a switch to 100% EVs would result in significantly increased electricity consumption powered by fossil fuels until renewables catch up, but lower overall carbon emissions since you're burning the fossil fuels more efficiently.
    - _ph_ 8y ago
      No. At best we could add 6% more electric cars per year - if only electric cars would be sold. That is the renewal rate for cars in Germany. This means, the energy consumption would increase by 1.5% per year. The addition of reneweable energy to the grid per year far exceeds the amount of energy that could be used by electric cars even at 100% market share. Which they are unfortunately far from. So the mix gets cleaner even after accounting all new reneweable energy for the electricity demands of electric cars.
      - reitzensteinm 8y ago
        It is simply not relevant that renewable energy is being added to the grid faster than EVs are increasing energy consumption. If you add energy consumption to the grid, you are powering it with your dirtiest power, which you'd otherwise be shutting off. EVs are still superior when powering them entirely with fossil fuels. I'm not trying to argue against them. But it's important to be truthful about where the energy is coming from.
        _ph_ 8y ago
        The argumentation with the marginal mix sounds nice, but is wrong. You cannot assign a certain power source to a certain electrical device unless they are directly connected. Your lightbulb isn't running on 100% coal, just because you switch it on. Yes, if there is a difference between the demand and the amount of reneweable energy produced, that has to come from carbon sources. So increasing the demand might increase that. On the other side, in Germany we are already at the point where we have excess energy production. Mostly because coal and nuclear plants cannot be throttled quickly. So quite often we have to take reneweable energy off the grid to keep it stable. Equally, we have negative electricity prices on the spot market. Here you would even have to calculate a negative CO2 content in the energy mix for electric cars which could absorbe that wasted reneweable energy. In the end, electric cars are rather accellerating than slowing down the switch to more renweables in the mix and as said, the addition of reneweable sources far exceeds the addition of electric cars - at the moment even by orders of magnitude.
sliken 8y ago
Keep in mind that 600TWh/year is likely a capacity of at least double that. But the peak rate is only under worst case scenarios like a sustained heat waves. Unfortunately that high peak capacity is very expensive and goes unused for the majority of the year. Electric cars consume quite a bit of power, but the longer range cars like the Audi, Jaguar, Tesla, top of the line leaf, and bolt all have a 200 mile or so range. So under normal use (somewhere around 12,000 miles a year) they don't need charged every day. So generally cars can charge off peak, but in times of dire need I can see only allowing cars to charge when there's a surplus of power... strangely enough these surpluses are becoming common because of solar. Sometimes utilities even have to pay to get rid of the power.

by _ph_ 8y ago

reitzensteinm 8y ago

I'm not surprised the German numbers are better. But even there, with Germany's remarkable progress, a Tesla bought today will be scrapped before Germany reaches 120% of today's electrical production in renewables. Fair enough; I should have used 25% instead of 50%. In my head I was multiplying by the energy efficiency of electrical production but that of course is not relevant to this calculation. The irony of correcting a bad argument with a bad argument while complaining about the same is not lost on me. I believe my point stands.

_ph_ 8y ago
In Germany, far more reneweable power is added to the grid as the consumption could increase. With about 44 million cars on the road, every year 3 million new cars are sold, so it would take 15 years to add that extra 10-15% of electricity consumption to the grid. Whether the grid reaches 100% reneweable during the lifetime of an electric car bought today or not might not be clear, but the point being was, it is guaranteed to contain way more reneweables as of today and with that the base of the calculations was wrong.
- reitzensteinm 8y ago
  If you're adding marginal consumption to the grid that does not exist today, you can't account for it as being in part powered by renewables. You are producing no more renewable energy than previously, and fossil fuel consumption will increase by exactly the amount you're adding to the grid. I'm not arguing that EVs aren't a good idea. I'm just in favor of being clear about the choice that's being made; a switch to 100% EVs would result in significantly increased electricity consumption powered by fossil fuels until renewables catch up, but lower overall carbon emissions since you're burning the fossil fuels more efficiently.
  - _ph_ 8y ago
    No. At best we could add 6% more electric cars per year - if only electric cars would be sold. That is the renewal rate for cars in Germany. This means, the energy consumption would increase by 1.5% per year. The addition of reneweable energy to the grid per year far exceeds the amount of energy that could be used by electric cars even at 100% market share. Which they are unfortunately far from. So the mix gets cleaner even after accounting all new reneweable energy for the electricity demands of electric cars.
    - reitzensteinm 8y ago
      It is simply not relevant that renewable energy is being added to the grid faster than EVs are increasing energy consumption. If you add energy consumption to the grid, you are powering it with your dirtiest power, which you'd otherwise be shutting off. EVs are still superior when powering them entirely with fossil fuels. I'm not trying to argue against them. But it's important to be truthful about where the energy is coming from.
      - _ph_ 8y ago
        The argumentation with the marginal mix sounds nice, but is wrong. You cannot assign a certain power source to a certain electrical device unless they are directly connected. Your lightbulb isn't running on 100% coal, just because you switch it on. Yes, if there is a difference between the demand and the amount of reneweable energy produced, that has to come from carbon sources. So increasing the demand might increase that. On the other side, in Germany we are already at the point where we have excess energy production. Mostly because coal and nuclear plants cannot be throttled quickly. So quite often we have to take reneweable energy off the grid to keep it stable. Equally, we have negative electricity prices on the spot market. Here you would even have to calculate a negative CO2 content in the energy mix for electric cars which could absorbe that wasted reneweable energy. In the end, electric cars are rather accellerating than slowing down the switch to more renweables in the mix and as said, the addition of reneweable sources far exceeds the addition of electric cars - at the moment even by orders of magnitude.

sliken 8y ago

Keep in mind that 600TWh/year is likely a capacity of at least double that. But the peak rate is only under worst case scenarios like a sustained heat waves. Unfortunately that high peak capacity is very expensive and goes unused for the majority of the year. Electric cars consume quite a bit of power, but the longer range cars like the Audi, Jaguar, Tesla, top of the line leaf, and bolt all have a 200 mile or so range. So under normal use (somewhere around 12,000 miles a year) they don't need charged every day. So generally cars can charge off peak, but in times of dire need I can see only allowing cars to charge when there's a surplus of power... strangely enough these surpluses are becoming common because of solar. Sometimes utilities even have to pay to get rid of the power.