Generation Expansion Planning Model Towards Decarbonization: Assessing the Dunkelflaute

Generation expansion planning is crucial for achieving net-zero emissions, involving decommissioning fossil-fuel units and replacing them with renewable energy and storage systems. Determining the optimal resource mix to maintain network reliability and cost-effectiveness is complex, particularly during periods of low renewable output due to weather variability. This paper explores the required capacity of renewable and storage resources for an isolated grid in long-term planning, focusing on integrating intermittent and limited resources to meet network constraints. The study also examines the impact of Dunkelflaute events on capacity planning and demonstrates how a balanced mix of variable renewable energy can mitigate network challenges. Using a modified IEEE-RTS system and realworld renewable data, the effectiveness of the proposed method is validated through extensive simulations. The results highlight the strategic importance of investing in renewable energy resources and storage to reduce costs and emphasize the role of storage in minimizing load shedding during periods of low wind and solar availability.