Solar panel mining farm

Hello community , I am mining BTC for 4 month now with 2 Antminers . I am looking forward for investing into solar panel farm . In the last video I saw that you are doing a solar panel farm and your electricity will be free ! How did you accomplish that , like you will have batteries or you will just sell the electricity that you generate trough the day and with this money you will pay the mining’s electricity :?

Its free, as in he will be generating his own electricity. but some localities also have a system to buy excess power created.
also most solar setups have a battery to hold power when the sunlight isnt hitting the panels, assuming your creating more than you use.