Yes, if your system is connected into the electricity grid, and assuming your house is already connected to the grid. Your installer will connect your system for you, if permitted – see below. The way to sell your electricity back to the grid is via the Smart Export Guarantee Scheme (SEG) which you can arrange with your electricity supplier or another one. Electricity suppliers decide the price they will pay you for your electricity. As of April 2022 best rates are around 5p per kWh. You can find SEG rates for different electricity suppliers here.