So I have a 20KW solar array. Love it. But it has one big problem for me that is surprisingly hard/expensive to solve: If the grid power goes off, so does the solar array.
That’s because the solar array feeds into the grid with me taking what I need first. But if the grid isn’t up, the solar array has to shut down because it is no longer connected to the “circuit”. Besides that, you wouldn’t want to run your house where the power could go on and off randomly based on clouds moving in the sky.
The solution is to have a battery sink for the solar array. The solar panels feed the batteries and if the power goes off, the house uses the batteries until they run out with the solar array feeding the batteries as best they can. However, it turns out that those batteries can be expensive. Very. Very expensive. As in tens of thousands of dollars expensive.
My house has a backup generator already in the event that power goes out. But in a true Zombie apocalypse scenario, my solar array would be worthless.