We propose the use of batteries of electric vehicles parked at a facility for temporary storing electric energy used by a grid-connected microgrid. We develop an optimization model which includes the uncertain storage capacity of the electric vehicles to manage the energy. We perform an extensive analysis to assess the economic effects of integrating the parking facility into the microgrid. We use Bender’s decomposition to solve the model. We run our simulations on the 14-bus distribution test system.