Cooperation of Offshore Wind Farm with Battery Storage in Multiple Electricity Markets

Wind power generation plays a critical role in meeting the energy demand in Denmark. Due to increasing penetration of renewable energy, and in particular wind power, the frequency deviation has become a national problem that needs to be solved urgently to continue the positive development of renewables. In this paper, a co-optimization method of an offshore wind farm with the battery energy storage system (BESS) is proposed which enable the wind farm to participate in both days ahead (DA) electricity market and primary frequency control reserve market. The optimization problem involves the hourly bidding energy, charging and discharging status which creates a mixed integer nonlinear programming (MINLP) problem. The bilinear term is linearized using big M method in this work and thus the facilitate the conversion from a MINLP to a MILP problem. The results show that the wind farm owner can obtain more profits if they want to provide ancillary service using the proposed bidding strategy. It is expected that such proposition could ensure market and political support for continuous wind power installations in Denmark.