it duplicates the price, but still cheaper than the grid. and you have backup when the grid goes down. giving excess to the grid using virtual battery (tax free) and then consuming it later is still better deal than mining. for the saved amount, buy BTC. do you actually do this BTW?

Regarding if solar+batteries give cheaper energy than the grid, it's vastly depends! Where and when in the world you are. It's not always that case. You are assuming too much things, sorry. Regarding virtual batteries: that's why I said: "all while maintaining independence of the possible grid surpluses subsidies." 🤷

"Sending power to the grid and then consume it later" is sometimes tricky. Depends on the contract - devil could be in "small letter's paragraphs". Many times you sell power for low price (it's a sunshine, spot price is low) and buy it expensive afterwards (it's a winter). Just small note, that the cost savings are not always as expected ones.

Regarding solar panels price right now:

Evolution of solar panels price:

if you don't have batteries, you are covering only small part of 24h of your consumption. still reliant on grid. also, panels take a lot of space, so overproduction takes space, costs money and ROI is smaller. panels are cheap, but you need often permission to build more and of course inverter (you can't connect infinite amount of panels to an inverter) and then you don't even mine enough to buy energy for night for that money. if you had batteries, it would be better. 😀

You are thinking on solutions in order to minimise a solar installation and make it more useful (through batteries) based on some existing energy consumption and needs. I'm proposing a way to consume (already existing) wasted solar energy through home #bitcoin mining. They are opposite views. 🤷