Energy management strategies for base stations powered by the smart grid

In this paper we study the problem of energy management in cellular base stations powered by smart grids and renewable energy. The utility company, through the smart grid, offers hourly-varying electricity prices made known a day ahead to the base station. We formulate an optimization problem in which the cost function is defined as the billing cost of the energy consumed each day. We seek to minimize the cost function while meeting the energy demand of the base station. We assume that the base station is equipped with a finite-capacity battery and a renewable source of energy such as a solar panel. The battery incurs charging and discharging losses which are accounted in the problem formulation. We find the optimal energy management policy using linear programming techniques. Furthermore, we study how the optimal cost is affected by several system parameters such as: initial state of the battery, its capacity, maximum charging/discharging rates, losses, smoothness of the price profile and correlation between the price and the consumption profiles. Our results show that significant cost savings can be achieved by properly scheduling the battery.