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Comment by derekp7 | Hacker News Reader

So how would this work? During the daytime, you have your car with you at work, away from your solar panels at home. When your car is at home, it is night, so it is not charging then. During a power outage, are you really going to drain your source of transportation to power your house? Especially if you don't know when the power is coming back on to refresh your car batteries? I know I wouldn't -- I'd just fire up a gas generator when the power goes out for an extended time, and use that to also recharge the electric car.

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During the daytime, your solar panels are dumping power onto the live grid. The same grid your car at work is plugged into. And all your neighbors'. And every other car in the garage or parking lot.

During an outage, unless it's a weather-critical incident or a disaster, the convenience of not needing to go and power a generator (and thus mess with needing to refuel it, and depleting your supplies which will be more useful in a real disaster) would likely be better. If it makes sense to power up a generator, then do that. It would also be charging your car.

We have this situation already in Austria.

Solar panels dump power onto the grid and you get paid by industry electricity price. But at night solar panels don't produce and one has to pay "consumer" electricity price that is 7 times higher!

So a battery system that covers nights and that has a durability of at least 10 years and with a price tag that allow for a amortisation within 8 years would be the way to go.

>During a power outage, are you really going to drain your source of transportation to power your house?

It's important to look at the numbers here.

An 85 kWH battery can drive 300 miles, or power the typical household for 3 days. Why wouldn't you power your house for a day if only meant 100 miles less range? How long are you expecting the power to be out? You may have a gas generator, but not everybody does. And if your car could act as a UPS until the generator kicked back in, why not?

You don't just have one battery, you can have multiple. So for example first day you charge battery 1, next day you use battery 1 and charge battery 2, next day you use battery 2 and charge battery 1, etc...

It's not about "the" outage (a rare event), its about all of the batteries working together to make that event even rarer and make the grid more robust during normal operation.

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