[icc97]

Electric cars are the real world example of loose coupling. Once your car is electric the source of the electricity can change (from Coal -> Gas -> Solar) and you don't have to change your car even slightly.

So it doesn't matter about any of the arguments about whether an electric car is more efficient or not when the electricity comes from coal.

What matters is that having electric cars enables us to move to a future of solar and wind and not notice the difference.

Plus having electric cars that don't pollute in cities where there are lots of people and generating the electricity with coal fired powerstations outside of cities where there are less people has immediate benefits.

[sergiosgc]

> Plus having electric cars that don't pollute in cities where there are lots of people and generating the electricity with coal fired powerstations outside of cities where there are less people has immediate benefits.

While this is true, much as the rest of your comment, this sentence has made me think that pushing pollution away from the eyes of people is a really negative effect of electric cars. If pollution is not in my backyard, I'll certainly be less aware of it, and hence I'll certainly pressure less for reduction.

[icc97]

I kind of hope not. As bgarbiak points out [0], there's other things that we start talking about once the pollution of fossil fuels is out the way.

Also once people have electric cars the incentive to have solar panels on your roof becomes bigger. Then once enough electricity is generated through that the coal power stations just get turned off because they're not needed.

Plus there will still be the issue of CO2 generation, just that drivers won't be responsible any so like ex-smokers (who in my experience seem to be more anti-smoking than most) they'll probably be even more offended by the polluting power stations.

[0]: https://news.ycombinator.com/item?id=14966321

[bgarbiak]

I'm as big fan of EVs as the next guy, and would love to see cities with clean air and no noise. But, there are few things that we forget about when we talk about zero-emmision cars.

EVs pollute less, but they pollute too, and in cities as well. They emit dust (including the most harmful particles: PM10 and PM2.5) from break discs and tires. Difference between CO2 in power plants and in city centers matters, but not that much. Once it's in the atmosphere the damage is done. As for NOx, the biggest offender in the dieselgate, Mazda's engines should not emit these.

Add a fact that in the current grid setup most of the energy is coming from coal, and that it's very unlikely it is going to change in a near future (mainly due to political reasons). Also, the waste from batteries is really ugly.

Given all that factors a 30% less polluting combustion engine is almost too good to be true. From a macro perspective the gain for environment is on par, if not better, than from electric cars.

My biggest problem is to believe in the numbers Mazda provides. Have to wait and see.

[icc97]

My main point was the loose coupling and getting off the hook from fossil fuels.

I shouldn't have made the point about city pollution as it just diluted the main point.

Nevertheless, the brake discs won't be any worse in electric cars, so it is an absolute reduction in pollution in cities. I've also only heard such things getting raise ever since we started talking about electric cars. When everyone is worring about NOx we forget about all the other polluting steps.

Coal power stations are the worst case scenario for electric cars and even with this things are on a par. But back on my main point with electric cars we can switch to Gas fired power stations and then to our own solar powered roof. With a Mazda ICE you're stuck on petrol.

Plus petrol in the long term can only get more expensive and solar can only get cheaper. Petrol is eventually going to run out and before that happens it's going to get very expensive. Solar panels and batteries will only get more efficient and cheaper to produce.

Battery recycling is definitely an issue and Elon Musk has quoted at the gigafactory opening that they can take all Tesla batteries back an recycle them fairly efficiently as their robots can strip the batteries apart as they have the schemas. Whether other car manufacturers follow suit is open to question.

As far as political reasons go, if everyone is driving electric cars I'm sure there will be much more political pressure to remove the polluting power stations because now CO2 is primarily the fault of the power stations rather than people driving around in their cars.

[bovine3dom]

> From a macro perspective the gain for environment is on par, if not better, than from electric cars.

Citation needed. It seems obvious to me that a huge power plant is going to be less polluting per kWh than a tiny little engine in a car. Otherwise, we'd use tiny little car engines to power everything - which only happens at the moment in places where they cannot get electricity by other means (building sites etc).

[bgarbiak]

You would be right if we could transfer the energy from power plant to cars efficiently. We can't. Batteries are the bottleneck. See: https://www.autovistagroup.com/news-and-insights/swedish-stu...

However, I have to agree that my previous comment _wrongly_ implied that burning coal at the plants to power the electric cars is the main issue we have to deal with.

[_wmd]

Don't forget that electrical grid transmission losses cause massive efficiency problems before centrally generated power ever reaches that car charging point -- on the order of 30% or more, and conversion from AC to DC at the charging port may account for another 10-30%. (Made up numbers, but they're in well within range IIRC)

I don't think it follows that just because we have historically centralized power generation, this was obviously due to efficiency. For example, centralization of management, investment, pollution control, logistical (fuel delivery), safety (nuclear) and reliability concerns seem far more obvious to me, although I don't doubt there could be an efficiency benefit to large-scale generation, I've just never heard of it.

[kw71]

> conversion from AC to DC at the charging port may account for another 10-30%

Simple rectification has not so much loss, I think you are thinking about low voltage DC power supplies, and I think that chargers for large, high voltage battery piles are likely to be happy with rectified (maybe doubled) mains supply.

The low voltage supply is first rectifying the input, then using an inverter to generate high frequency AC, then rectifying and filtering this to give a DC output.

[londons_explore]

Large AC -> DC conversion has to do this too.

The simple "diode" rectification is no longer acceptable due to harmonics put on the AC side causing grid stability problems and emitted radio interference.

[JshWright]

> Add a fact that in the current grid setup most of the energy is coming from coal

Coal represents less than a third of North American power generation, and less than a quarter of generation in Europe. In Brazil (another major car owning country) coal only represents ~1% of their generation sources.

Really the only place your statement is true is mainland Asia, and even there the market share of coal is falling (and the number of cars there is dwarfed by the number in NA/Europe/Brazil).

[reacweb]

EV should consume less brake discs because small braking recharges the battery.

[icc97]

How does that work? I always assumed that they were still using the disc brakes but harnessing that somehow to recharge the battery

[secmax]

That is/could be true for hybrid cars too.