Battery storage is profitable if you can sell for more than you buy. It just needs to be connected to the grid and not necessarily connected to a particular generator.
Although battery storage may still be located close to generation. One benefit of this is that you get more benefit from your grid connection. Without batteries you can just export for a part of the day. With batteries you can export when it is sunny/windy, export when it is dark/not windy, and even import energy when wholesale prices are cheap. The expensive grid connection is better utilised.
Although battery storage may still be located close to generation. One benefit of this is that you get more benefit from your grid connection. Without batteries you can just export for a part of the day. With batteries you can export when it is sunny/windy, export when it is dark/not windy, and even import energy when wholesale prices are cheap. The expensive grid connection is better utilised.