The Application of Super Capacitors to relieve Battery-storage systems in Autonomous Renewable Energy Systems

The utilization of wind and sun as renewable sources causes uncontrollable fluctuations in power generation. Furthermore, the ratio between peak power and average power is high for systems with a limited number of households. In small autonomous renewable energy systems (ARES), energy storage is needed; however, the use of Lead-acid batteries as energy buffers is problematic, since it is not possible to cover fast power fluctuations without dramatically reducing the batteries´ lifetime. In this paper Super Capacitors are applied to relieve fast changes in the battery storage system. Batteries are used to meet the energy requirements and Super Capacitors are used to meet the instantaneous power demand. At the end of this paper, a sizing method is proposed for the Super Capacitor system.