Assessment of Firm Capacity in Hybrid Systems: A Dubai Case Study on ESS Sizing

Aiming for carbon-free power systems for future grids has challenges in providing the necessary firm capacity from a power engineering perspective. During capacity planning studies, the variability of renewables can lead to periods of zero firmness, necessitating nonrenewable generation technologies to be added to the candidate list to ensure firmness. However, hybrid systems can provide limited firmness and lower the need for nonrenewable resources. This paper investigates the temporal firmness of the various sizes of energy storage systems combined with a 1MWp photovoltaic system. Using real-time data from a site in Dubai, the framework simulates system performance hourly and monthly over an entire year. The analysis reveals that hybrid system firmness is affected by seasonal variations in PV output and is highly sensitive to the storage capacity. The study further demonstrates how different storage capacities affect the system’s ability to maintain firm capacity.