Putting solar panels on the roof doesn't change emissions from driving an electric car

Powered by wind and sun, or not?

Earlier, I wrote about what happens when we put renewables on the grid and how complex it is.

Now we get to the question of whether putting solar panels on your roof makes your driving emissions free, or whether having a green generation company does the job. The answer may not please some people, because the panels don't significantly alter the emissions of your driving, while the power company does -- but it shouldn't matter because they are equally good things to do.

Part two can be found at Putting Solar On Your Roof Doesn't Make Your Electric Car Driving Green, But This Might


If it were true that "every mile I drive in my electric car causes a corresponding amount of renewable energy to be generated," then it would also be true that "every amount of renewable energy I add to the grid causes a corresponding amount of renewable energy to not be generated."

Just as there are no "solar electrons," there are also no "solar dollars." What does "My money goes only to solar and wind plants" even mean? Your money goes into a bank account where it gets mixed with a bunch of other people's money, right? A solar and wind plant is going to generate a certain amount of energy and get paid a certain price for it, and I don't see how how much you drive affects those amounts at all.

Essentially, "every mile I drive in my electric car causes a corresponding amount of renewable energy to be generated" (and "every amount of renewable energy I add to the grid causes a corresponding amount of renewable energy to not be generated") if the entire grid consisted solely of renewable energy.

Adding solar energy to the grid during times when renewable energy does not meet all energy demands makes the world greener. Earmarking your dollars for payment to renewable energy sources....well, I'm still curious what that means. What happens if the dollars earmarked for payment to renewable energy sources is more than (or less than) the payment renewable energy generators are entitled to? If it's less, presumably the remainder of the payment comes from payers who haven't earmarked their payments. If it's more...I don't know...it probably isn't more, unless the whole thing is a lie. (What would you want to happen in that case? I guess rolling blackouts would be a possibility.)

(Maybe if the demand for renewable energy exceeds the supply, the excess could be carried over into a future period when the supply exceeds the demand? Maybe that would induce supply. Maybe not, though, as that future supply might have happened naturally anyway.)

On that note, I guess if the demand for renewable energy exceeded supply, and a homeowner wanted to make the best impact for their solar panel installation, they would sell their solar power they generate solely to people who do not insist on only buying green energy, right?

A new piece of research has just come out of the University of Canterbury Engineering department that shows if New Zealand replaced 40% of the ICE vehicle fleet with EVs by 2040, this would only result in a 1.7% reduction in emissions considering a whole-of-life approach to EVs. If we upgrade the grid, then this changes to 6.7%. New Zealand already has about 78% renewable energy, so what we can learn from this is that overall, EVs are unlikely to offer the emissions reductions that everyone thinks they will provide us.

That's just a powerpoint -- would like to see the actual math if they have it. Surprised to not see better results for NZ. Note that "Get more people to use the bus instead" is wishful thinking. You can't wish people onto the bus. The bus has to offer competitive convenience to the car for that to happen.

A fine article, but I would suggest that if a person installs solar panels because they bought an electric vehicle, then in some sense their EV is powered by their panels. They might decide panels will reduce their electric bill after the EV purchase. If so, then the amount of "green" electricity generated by their panels can be directly correlated with their decision to buy an EV. Eventually, they might have purchased panels anyway, but the acceleration in time of that purchase should be credited to the EV.

Well, people do think that, and they do indeed base purchases on that mistake, but it is still a mistake.

It depends entirely on the vehicles usage and parking arrangements. Panels on the roof would help 'trickle charge' the vehicle and keep power in it for protracted times on non use - such as parking at an airport for a couple of weeks of if used as an occasional vehicle. It can help to offset loss of charge, and in some instances it could have meaningful impact on power usage (for example a car used sporadically rather than constantly). I don't get why they don't all have them incorporated.

The point is that the panel is useful in only limited instances. It is much greener and much cheaper to put the panel somewhere else it can be useful all the time, like on a house roof. For most people, that long airport parking example is increasingly rare (for any really long parking stay, use of Uber is cheaper and better.)

It would be possible to rent a solar cover for a car parked for a long time if there were an easy place to plug it in.

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