My solar system is attached to the grid. This means that if my system is supplying all my electric usage for the day, whatever I'm not using is going back into the grid. If I don't have enough to power my electrical usage for the day, I get power from the grid, in our case, P.G.&E, the company that is going bankrupt due to being the cause of our forest fires earlier this year. My meter runs backwards all summer (I'm making my own electricity), but in the winter, I have so many pig blankets, tortoise heaters and lights that I use a LOT of electricity, more than my system can supply. Even with the solar power, I still end up paying about $2000 at the end of the year.
So, $2000 for what period of time? Nice you can use solar during the Summer. I have two small panels tied to a bunker of 12v batteries connected to a solar charge controller to a DC to AC converter that we use to power small appliances, even our internet when power is down.
So jealous of those cactus!