EV-integrated and grid-connected hybrid renewable energy system: a two-stage optimization strategy

Driven by net-zero strategic goals, the renewable energy and electric vehicle sectors have experienced unprecedented growth. To address the variability of renewable energy, integrating electric vehicles with renewable energy sources has emerged as a key strategy, this hybrid approach not only improves energy efficiency but also enhances supply-demand balance and stabilizes energy supply, thereby advancing sustainable development. This paper proposes a two-stage optimization model for designing and managing such systems: the first stage concentrates on determining the size and capacity allocation of system components, while the second stage handles the operational management of battery and electric vehicle charging demands. To mitigate the uncertainties of renewable energy, a rolling optimization strategy is applied, enabling real-time and forecast-based operational decisions. Compared to system designing with rule-based operational management, the two-stage optimization method significantly improves the economic and operational stability, reducing the levelized cost of energy and operational expenses by up to 9.51 % and 5.49 %, respectively. Seasonal analysis shows higher battery utilization in summer and winter, suggesting potential cost savings through seasonal leasing of additional storage capacity. The proposed sizing and management approach offer ease of implementation and excellent scalability for grid-connected hybrid renewable energy system incorporating electric vehicles.