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At 40% coal provided electricity, electric cars are already way less poluting than combustion engines. Actually even just being powered by an efficient diesel g

by _ph_ 7y ago

At 40% coal provided electricity, electric cars are already way less poluting than combustion engines. Actually even just being powered by an efficient diesel generator would put them on a roughly equal level. So only 40% coal is already a benefit. But of course, we should get rid of our coal plants as quickly as possible. That is the one rather low hanging fruit in reducing the carbon footprint. And I think the 2038 number won't stand, the ramp-down will be far quicker now that climate change has finally gotten more awareness. So, while not reaching the optimal numbers right now, any electric car bought today will still drive when the coal usage for the grid will be greatly reduced if not completely stopped. Any combustion engined car bought today isn't only worse in emissions already, it won't change, while the electric car gets "cleaner". Also, one should not underestimate the positive effect have on the rollout of reneweables as they can be charged at different times of the day, depending in the supply of reneweable energy.

_ph_ 7y ago
For all the downvoters: powered by the average German grid, a Tesla emits about 75g CO2/100km. Please show me any combustion engined vehicle that comes even close to those numbers. Of course the "emissions" of the electric cars can only get better from there.
- reitzensteinm 7y ago
  When you add load to a grid that's in the process of decarbonizing, you need to look at the marginal impact. Taking the average energy mix is bad math, because you're delaying the shutdown of the dirtiest sources. This can get more complicated if you have excess renewable energy generation at times, where the use is essentially free. Not to mention demand dispatch to smooth intermittent renewables. I'm a big EV fan, but it's important to get the math right, because overstating the impact does disservice to other options. Especially in Germany. When I lived in Berlin for two years, not in the loop, I just used public transport. Most of my friends rode to work.
  - _ph_ 7y ago
    The mix is the right math. After all, you cannot say, which electric device uses which power source. Or suddenly it might be your TV running on pure coal energy - this does not make much sense. The best approximation is, that you apply the average energy mix. Which might be even too pessimistic, as not only a lot of people do power their electric cars with their own solar energy but also it is easy to charge your electric cars especially in those times where the grid is on a relatively low carbon content and even surplus energy needs to be exported. Of course, there are plenty of better alternatives to cars in many places, especially city centers. But as long as there is a genuine need for cars, they better be electric than combustion engined.
    - reitzensteinm 7y ago
      The question that needs to be answered is, what is the marginal impact of taking an ICE off the road and replacing it with a BEV? Using the current mix of renewables is a form of double counting. No more renewable energy is being fed in to the grid, however more is coming from dirty sources. Reductio ad absurdum, what happens if all of Germany's cars were BEV overnight? I've seen estimates that the load on the grid would be increased by 20%. Surely you'd agree that using the current mix of renewables would no longer make sense calculating their environmental impact. So why does that change at the margins? The answer is that it doesn't. The math is the same. With the exceptions we've both pointed out.
      - socialdemocrat 7y ago
        At the margins Germany is primarily adding solar and wind. And this solar and wind benefits from having BEVs which can suck up excess production when needed.
  - socialdemocrat 7y ago
    If you look at marginal impact then BEVs have no emissions, because generating capacity is primarily growing in the renewable energy segment. In fact there is an even bigger benefits to BEVs: New BEVs are being made to allow sending current the opposite direction. Hence the BEV fleet can be used as a large battery for storing renewable in times of overproduction and selling it back when it is needed. In other words adopting renewable energy REQUIRES BEVs.
southerndrift 7y ago
Why would a diesel generator put them on equal levels? Even if you assume that an electric engine has 100% efficiency, you lose energy because * per amount of energy, batteries are heavier than gasoline tanks so accelerating needs more energy * charging batteries is not 100% efficient Is that all balanced by the generator operating at optimal conditions?
- _ph_ 7y ago
  A good diesel generator should have the peak efficiency of a diesel engine of about 40%. A diesel car can hit the same peak, but only at a certain speed/power output. So the average efficiency is about 20%. So there is a quite a marging for charging losses. The weight of an electric car usually is a minor component in the consumption, most is the aerodynamic drag. On top of that, electric cars can get about 60% of their kinetic energy back by using their motor as a generator.
- varjag 7y ago
  You burn a litre of oil fractions per litre of petrol/diesel output at the refinery. Something noone is eager to count in their efficiency comparison. Also, all electric vehicles use regenerative braking, recapturing the kinetic energy that is lost with ICEs.

by _ph_ 7y ago

_ph_ 7y ago

For all the downvoters: powered by the average German grid, a Tesla emits about 75g CO2/100km. Please show me any combustion engined vehicle that comes even close to those numbers. Of course the "emissions" of the electric cars can only get better from there.

reitzensteinm 7y ago
When you add load to a grid that's in the process of decarbonizing, you need to look at the marginal impact. Taking the average energy mix is bad math, because you're delaying the shutdown of the dirtiest sources. This can get more complicated if you have excess renewable energy generation at times, where the use is essentially free. Not to mention demand dispatch to smooth intermittent renewables. I'm a big EV fan, but it's important to get the math right, because overstating the impact does disservice to other options. Especially in Germany. When I lived in Berlin for two years, not in the loop, I just used public transport. Most of my friends rode to work.
- _ph_ 7y ago
  The mix is the right math. After all, you cannot say, which electric device uses which power source. Or suddenly it might be your TV running on pure coal energy - this does not make much sense. The best approximation is, that you apply the average energy mix. Which might be even too pessimistic, as not only a lot of people do power their electric cars with their own solar energy but also it is easy to charge your electric cars especially in those times where the grid is on a relatively low carbon content and even surplus energy needs to be exported. Of course, there are plenty of better alternatives to cars in many places, especially city centers. But as long as there is a genuine need for cars, they better be electric than combustion engined.
  - reitzensteinm 7y ago
    The question that needs to be answered is, what is the marginal impact of taking an ICE off the road and replacing it with a BEV? Using the current mix of renewables is a form of double counting. No more renewable energy is being fed in to the grid, however more is coming from dirty sources. Reductio ad absurdum, what happens if all of Germany's cars were BEV overnight? I've seen estimates that the load on the grid would be increased by 20%. Surely you'd agree that using the current mix of renewables would no longer make sense calculating their environmental impact. So why does that change at the margins? The answer is that it doesn't. The math is the same. With the exceptions we've both pointed out.
    - socialdemocrat 7y ago
      At the margins Germany is primarily adding solar and wind. And this solar and wind benefits from having BEVs which can suck up excess production when needed.
- socialdemocrat 7y ago
  If you look at marginal impact then BEVs have no emissions, because generating capacity is primarily growing in the renewable energy segment. In fact there is an even bigger benefits to BEVs: New BEVs are being made to allow sending current the opposite direction. Hence the BEV fleet can be used as a large battery for storing renewable in times of overproduction and selling it back when it is needed. In other words adopting renewable energy REQUIRES BEVs.

southerndrift 7y ago

Why would a diesel generator put them on equal levels? Even if you assume that an electric engine has 100% efficiency, you lose energy because * per amount of energy, batteries are heavier than gasoline tanks so accelerating needs more energy * charging batteries is not 100% efficient Is that all balanced by the generator operating at optimal conditions?

_ph_ 7y ago
A good diesel generator should have the peak efficiency of a diesel engine of about 40%. A diesel car can hit the same peak, but only at a certain speed/power output. So the average efficiency is about 20%. So there is a quite a marging for charging losses. The weight of an electric car usually is a minor component in the consumption, most is the aerodynamic drag. On top of that, electric cars can get about 60% of their kinetic energy back by using their motor as a generator.
varjag 7y ago
You burn a litre of oil fractions per litre of petrol/diesel output at the refinery. Something noone is eager to count in their efficiency comparison. Also, all electric vehicles use regenerative braking, recapturing the kinetic energy that is lost with ICEs.