Two-stage Integrated Planning Strategy for Future Power System Expansion with Optimal Energy Mix and High Renewable Penetration

Decarbonizing energy sources by enhancing renewable energy contribution is essential for most countries to achieve sustainability goals. Therefore, it is important to quantify the share of renewables in the future energy mix and evaluate their impact on power system expansion without sacrificing the reliability and performance of the grid. This paper proposes a two-stage planning strategy for grid extension with an optimized energy mix incorporating the assessment of a detailed grid model. The first stage accounts for future energy mix planning and power plant dispatch models covering a timeframe from subhourly to decades. The second stage exploits detailed network models to verify the deployment plans and network performance under diverse intermittency behaviours from renewable resources. The two-stage demarcation significantly reduces the complexity of the integrated energy mix optimization and provides flexibility in fine-tuning the power plant capacities, locations, and other grid upgrade decisions. The proposed strategy and the possible scale-up opportunities are elaborated in detail through a case study problem. The insights extracted from the case study may be of interest to energy policymakers, planners, and investors.