When energy prices went crazy in the UK a while back I heard of some people getting under a year payback times. My energy usage is much lower than theirs so it would take me quite a bit longer though. A lot of the costs are fairly static.

At this point a battery alone might be a better investment. Cheaper install and using off peak rates to charge could drop my per unit costs from 24 to 8. But I think even that would take years to pay for myself. It's also annoying because the grid should already be fucking doing this! Why should I have to do it myself in a setup that is going to be far less efficient in costs than doing it at grid scales with bulk buying of batteries?

The tech exists today, I can buy it.