Article
Performance Evaluation of Hybrid Renewable Energy Storage Systems
: Renewable energy sources such as solar photovoltaics and wind are inherently intermittent, and energy storage is essential to match their fluctuating output to the load. No single storage device combines high energy, high power, long life, and low cost, which motivates hybrid energy storage systems that combine complementary devices. This paper evaluates the performance of a hybrid renewable energy storage system supplying a stand-alone microgrid from solar PV and wind, in which a lithium-ion battery is combined with a supercapacitor and coordinated by a frequency-based energy-management strategy. A model of the generation, storage, and control is developed, and the system is assessed through simulation using round-trip efficiency, battery state of charge, dynamic power sharing, loss of power supply probability (LPSP), renewable fraction, and levelised cost of energy (LCOE) as performance metrics. The results show that adding a supercapacitor smooths the battery state of charge, removes high-power transients from the battery, and improves the round-trip efficiency from about 88% to 92% while lowering the LCOE to about 0.29 $/kWh. A storage capacity of 125–150 kWh is found sufficient to meet a 1% reliability target, and an optional hydrogen pathway further improves reliability at the expense of efficiency and cost. The battery–supercapacitor hybrid is identified as the most favourable configuration for typical renewable microgrid operation.
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