There are two types of systems, the one connected to the NETWORK and the independent one called Off Grid or autonomous. If you live far from the distribution network, you must make a system with batteries, this is the Off Grid. If, on the other hand, you already have electricity from a distributor, put your solar panels, you do not need batteries, this is the so-called “Connected to the Network”. Their energy generated in times that is not consumed, deposits them to the external power grid. Your meter turns upside down and counts energy as a credit in your favor, taking it at night or in rainy weather for example, at a much lower cost, this is called the access or net rate.