Home installations just cut it off. In both of these cases.
I did my own battery backed installation. When I'm underproducing I can shed load (I turn off my AC - almost always that's enough, and it's automated by relay). When I'm overproducing (ex - my battery is full and my load is still not enough to consume input) I just don't let the panels generate more current than I can consume.
Managing grid scale power is different concern, and not particularly relevant to small household generation. Especially not relevant in the 800W category for "balcony solar" (which is much smaller than what I'm working with).
Solar is fucking coming, whether you continue to shove head into the ground or not.
It's just way more affordable. Getting easily more affordable as batteries continue to improve.
I honestly doubt I'll still be connected to a local utility grid for electric 10 years from now, and I live in a region of the US that has considerably cheaper grid power than most areas.
My current EV has a 38kW battery.
When it's too worn out for car use (SoH around 60-70%), it's still perfectly enough to run _everything_ in my house for multiple days - except for the electric sauna, and I'm smart enough to turn it on if there are production issues :D
There's a reason why EV's will never be as cheap as the cheapest ICE shitbox. Just the bare metals in the battery are worth thousands when recycled, even more if the battery is still viable.
The value of the metals will depend a lot on the battery chemistry. LFP batteries don't need nickel or cobalt and sodium-ion batteries can also replace the expensive copper foil on the anode with cheaper aluminium foil.
I'm somewhat sceptical that used batteries will ever be worth much other than as scrap given the cost and complexity in testing, installing, and managing a mixed set of used batteries in larger installations.
With new batteries halving in price every 4 years or so the value of the raw materials in old NMC batteries alone should make it economical to sell for scrap and buy new batteries for stationary use cases after 10 years or so!
If you ever are looking to implement that EV battery as house backup, this repo might be useful: https://github.com/dalathegreat/Battery-Emulator
I did mine with it and old leaf 24kwh battery (~60k km). After all the safety margins I get ~15 kwh out of the battery.
Sorry, the consequences are too dire for me to delegate household battery control to a vibe-coded project.
I'm curious what your home insurance provider has to say about your installation.