A single Tesla powerwall has 13.5kwh of usable energy. An average Tesla car has between 70-100kwh of usable energy. The average American home uses about 30kwh/day (https://www.eia.gov/tools/faqs/faq.php?id=97&t=3). There are about 141 million houses in the US. There are 275 million personal and commercial vehicles in the US. So there would be plenty of capacity once you replace a significant chunk of those vehicles with EV.
Cloudy weeks don't occur over large areas - if you look at solar or wind production over an entire county or state, for example, it varies very little (that's also the advantage of using both sun and wind - when one is bad the other is typically good). So the solution to intermittency is mass adoption.
I live in a 1000 square foot two bedroom condo. When it gets below 20° f, which does a lot during the winter, I have to use the auxiliary heat on my heat pump unit.
That's 7.5 kW.
So just to stay warm during the night, when solar stops working, I would need 3-5 Power Walls?
Get a better heat pump that doesn't need aux heat? I know Mitsu "hyper heat" minisplits advertise high efficiency to -10F.
Powerwalls are overpriced for their capacity. Grid storage operators pay ~$150/kwh for batteries, then I'd guess about the same for charging/inverter electronics. I also see EV West sells 3.5kwh Samsung batteries to average consumers for $700 (I'm sure they're charging a large markup as well).
Lol. Was just offering suggestions you may have not known about. Off-grid isn't practical for many people who aren't willing make sacrifices just for the sake of it. Some people like the challenge and lifestyle. Renewable power plants are more efficient than residential. I think used Leafs can be pretty cheap, and even new EVs, solar panels (grid-tied), and more efficient appliances can save you money in the long run. Not sure if it makes sense to sell EV charge back to the grid (I guess it does if the price is right).
I've heard of some people on certain electricity plans overheat or overcool their house when electricity is cheap to save money (acting kinda like storage for when electricity is more expensive).
Nice to meet you MrFagtron
An EV would be a much better investment than powerwalls but it’s hard to be specific on a case by case basis. Hope that helps MrFagtron.
In regards to V2G. Tesla is not even supporting bi-directional charging at this point and it is just now starting to become a bit more common in newer models. It would be interesting to see more detailed example about this. You would also need to include the usage of industry and commercial which as far as I know together account for more than residential usage. How about availability in terms of SOC and being plugged in or not. I think this is a bit more difficult to solve than you are alluding to but I'm happy to be proved wrong.
This is a far easier problem and solution than building a nuclear reactor. And it’s utilizing something (EVs) that we need anyway so improved utilization of resources.