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Comment by zmmmmm | Hacker News Reader

> I think the article still doesn't address the mismatch between solar energy production and consumption, which needs to be filled by storage mechanisms

There's going to be a beautiful synergy here between electric vehicles and solar. Because an EV battery is already easily enough to power most houses through 14-16 hours of darkness, so if it can be a sink for solar during the day it can then be a source during the night. The future will have a combo of residential battery storage and V2H/V2G which has an attractive property that it scales naturally with population (every new person that moves to a location brings their EV battery with them).

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We usually drive to work. That means that when the sun’s shining, the car isn’t home.

Conversely, if we didn’t drive to work, we probably wouldn’t have a car.

On the other hand, we have a big solar array at work so if we had on-site parking (we don’t) we could drive our power home.

It’s probably impractical in reality though, the tax treatment would be chaos and we use the power we generate at work during the day on-site.

Nobody said that you have to use your home or work solar. If you fill up part of your car using some fast charger network (which would still be solar powered), it would still work.

Moreover, even if we take the top 25% percent of commute distances (which is >40km per day), that still leaves you with 10 days until you have to recharge. If you recharge every weekend, you still have plenty of battery capacity for your needs outside of sun hours (you likely will need only 1-2 kWh per day anyway).

I can't see how this could be true. Many people will need to drive the ev to work during the day, and if you discharge it at night then when are you really charging?

It may be true for some who WFH often or in some cases, but not enough EVs will be able to discharge overnight for a v2g battery revolution.

Yes, it does rely on charging infra rolling out - either at work or with fast DC charging. But that is happening too. Well, in markets where EV adoption is encouraged - for the US, I guess we'll see.

Ideally in that case you’d charge the car from the grid during the workday, when the grid is powered by solar and power spot prices are low.

BYO house solar is optional when there is grid solar (and home solar exports).

There are several scenarios where it would contribute:

1. You have access to a charger at work 2. You’re retired 3. You take public transportation or bike to work (fairly common scenario in Europe) 4. Work-from-home (got more common after covid, I know many people who do it at least once a week now, and that’s generally enough to charge what you need to drive for a week) 5. You charge only during the day on weekends (should be enough to cover the week for most people, even if you feed say 20% of it back to the grid through the week) 6. Rental fleet operators (booking data can inform charge/discharge policy) 7. Residential batteries, where you charge the EV at night with what you got during the day, every day, but set up a policy where you allow both the home battery and the EV battery to discharge if the electricity is expensive enough. I could see myself making decisions about WFH or biking to work based on electricity pricing.

You're not left with a flat battery at the end of the night. Many vehicles are combined in intelligent systems which work together to ensure that the vehicles have the energy they need (which is easy to set in all the systems I've seen) but provide enough grid support to make this work.

Remember that even my little town car (Renault Zoe) has a 52kWh battery.... which would run my house for five days. So the energy stored in these systems can be considerable.

The people doing these things have thought a lot about it. Take a look at this video - it's a bit 'puff piece' but shows what one way of doing it looks like:

https://www.youtube.com/watch?v=fKItLGPdN0k

I think peak energy usage is in the morning and afternoon / early night when people are at home.

Would be stella if people could charge during noon. I don't know how feasible that is.

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