Optimal battery size for a green base station in a smart grid with a renewable energy source

Abstract

Green base stations, powered by renewable energy sources, have mainly been restricted to remote areas. In urban areas, recent technological advancements have strengthened the bidirectional power flow in microgrids (Smart Grids), giving the possibility of green LTE base stations acting as energy traders. To facilitate this trading, batteries are needed to deal with the inherent stochasticity of renewable energy sources. In this paper we provide a new technique for dimensioning batteries for a base station. We show how the solution depends on different boundary conditions set by the microgrid such as energy balancing cost, transaction fee and power price. The technique is based on a Markov decision process and considers uncertainty in traffic, renewable power production and power price in the microgrid. We also show how to quantify the energy balancing cost for the base station, supplementing current research on energy balancing in microgrids. The results show that for certain microgrid conditions, the value of modelling price uncertainty is insignificant. Also, the results show that it is never optimal to invest in more than the minimum required battery size given certain transaction fee and power price regimes.