This paper presents an optimal energy management strategy for a grid tied photovoltaic-wind-fuel cell hybrid power supply system. The hybrid systems meets the load demand consisting of an electrical load and a heat pump water heater supplying thermal load. The objective is to minimize energy cost and maximize fuel cell output, taking into account the time-of-use electricity tariff. The optimal control problem is solved using a mixed integer linear program with the supply switch to the heat pump water heater and the power from the grid, power to/from inverter, power to electrolyzer and from fuel cell the control variables. The hot water temperature inside the water storage tank and the hydrogen in the storage tank are the state variables. The performance of the proposed control strategy is tested by simulating different operating scenarios: with and without renewable energy feed-in, and the results confirm the effectiveness of the proposed control strategy, as it increases the supply reliability of the system.
Keywords