While "on grid" photovoltaic panel installations are connected to the grid to cover all your electrical needs, the peer-to-peer power supply is independent of the general grid. The photovoltaic panels will supply electricity to a specific substation. This solution is used for energy-intensive substations such as swimming pools or heat pumps.
For example, you can opt for solar energy only for some of your equipment that you do not wish to feed into the public grid.