Renewable Energy Integration in Power Systems: Optimal Dispatch, Battery Storage, and Operational Performance

Abstract

The increasing penetration of renewable energy sources, particularly solar and wind power, introduces significant operational challenges for modern power systems due to their variability and uncertainty. This study presents and evaluates a modelling and optimization framework to investigate the effects of renewable energy penetration on operating costs, carbon emissions, transmission losses, renewable energy curtailment, thermal generation requirements, and system flexibility. The framework is applied to a modified IEEE 39-bus test system incorporating conventional generating units, solar and wind generation, and a battery energy storage system (BESS). A multi-period optimal power flow model is used to evaluate four renewable energy penetration scenarios (0%, 20%, 35%, and 50%) over a 24-hour period. The optimization aims to minimize daily operating costs and carbon emissions while satisfying power balance, generator operating limits, ramp-rate constraints, transmission-line limits, and battery state-of-charge (SOC) constraints. The results indicate that daily operating costs decrease by 51.05%, from USD 1.898 million to USD 0.929 million, as renewable energy penetration increases from 0% to 50%. Daily carbon dioxide emissions decrease from 19.689 to 5.562 kilotonnes, while peak thermal generation decreases by approximately 38.81%. The 35% penetration scenario achieves the lowest transmission losses, with renewable energy curtailment limited to 2.65%. At 50% penetration, curtailment increases to 14.56%, primarily due to network congestion, minimum-generation constraints, and insufficient system flexibility. Optimized battery operation further reduces renewable energy curtailment, peak thermal generation, and the maximum thermal-generation ramp rate. These findings highlight the importance of coordinated energy storage, flexible generation, and transmission network enhancements in managing the operational challenges associated with high renewable energy penetration.