A comparative study between lithium-ion battery and Pb-acid battery-supercapacitor hybrid energy storage system for frequency control and Energy management of islanded microgrids

Abstract

Among various storage technologies used for the energy storage systems, the supercapacitors, the Pb-acid Batteries (PABs) and the lithium Batteries (LBs) are widely used for microgrid applications. The supercapacitors with highpower density are suitable for fast power regulations; conversely, the PABs have high-energy density, which makes them suitable for long-term energy management. Since the PABs and the supercapacitor can complement each other deficiencies, their combination as a hybrid energy storage system is used. However, the LB has both high-energy and high-power densities. Therefore, an LB ESS (LBESS) can similarly function like a Pb-acid batterysupercapacitor hybrid ESS (PSHESS). However, their topologies, life cycles and costs are different. This paper tends to determine which one is technically and economically more suitable for applications in islanded microgrids.For this purpose, a frequency control and energy management scheme is proposed. It maintains the balance between demand and supply, and also keeps the microgrid frequency within safe operational limits using the least needed sizes for the energy storage systems. Using the simulation results, the sizes and costs of the energy storage systems are determined. For a decade of operation, the PSHESS imposes almost 49.2% more cost than the LBESS which makes the LBESS more cost-effective.