The invention relates to a power control device for a power grid and to a method for controlling the operation of a power control device. To allow a consumer unit connected to the power control device to be supplied with energy in an optimized manner in accordance with its requirements, a power control device according to the invention is proposed, said device comprising a power generation unit, in particular a photovoltaic unit, for generating power from renewable resources, an energy storage unit for storing energy, a load connection unit for connecting the power control device to a consumer unit for consuming energy, a grid unit, in particular an inverter unit, for connecting the power control device to a power grid, for drawing energy from the power grid and for feeding energy into the power grid, and a control unit for controlling a flow of energy between the power generation unit, the energy storage unit, the consumer unit and/or the power grid.