Department of Electrical Engineering, Shahid Bahonar University of Kerman
This paper studies power management in a grid-tied hybrid energy system consisting of photovoltaic array, wind turbine, fuel cell, electrolyzer, hydrogen storage tank and a combinational heating system to supply the thermal and electrical demand of a building. Moreover, the hybrid system is capable of exchanging power with local grid. Thus, variable daily buying and selling tariffs are also taken into account so as to cover a wide range of operational conditions. The thermal demand is supplied by both electric heating system and the fuel cell exhaust heat. The paper formulates the matter in the form of a nonlinear constrained optimization problem and then evaluates several well-known heuristic optimization techniques. The performance of each of these algorithms is discussed in detail and the elite algorithm is introduced. Furthermore, the effect of the initial charge of the hydrogen storage tank on total operation cost and also charge remained are fully discussed. In order to fulfill this intention, a novel criterion is presented to determine the optimal initial charge. Finally, the price fluctuations of tank-stored hydrogen are examined. The validation of the results will be implemented based on simulations.