The modern electricity grid is composed by an increasing percentage of renewable energy installations. Given the intrinsic unpredictable nature of these sources of power generation, it is essential to integrate battery energy storage systems (BESS) so as to ensure stability of power grids. This work proposes a techno-economic analysis of the integration of a BESS into a wind power plant, useful for performing grid-level wholesale energy arbitrage. The purpose of the analysis is to optimize the size of the battery so as to ensure the greatest possible profit from its use. To do this, a mixed integer linear programming (MILP) optimization algorithm is used.