Energy Storage and Solar for New Peaking Capacity in North Carolina

Abstract

Solar power paired with battery energy storage is increasingly presented as an alternative to traditional natural gas combustion turbine technology for providing power during times of very high demand. This analysis uses hourly simulation of the Duke Energy Carolinas (DEC) electric system to compare the performance and cost of solar plus storage and new simple cycle gas turbine (SCGT) technology. The results show solar plus four-hour battery storage and SGCT perform similarly in addressing the peaking capacity needs of the system. Solar plus four-hour battery storage results in system-wide production cost savings compared to SGCT, but this savings is limited by the SGCT's greater displacement of older, more expensive peaking units and is outweighed in the short-term by higher fixed costs. However, If renewable technology improvements and cost reductions follow historical trends it is possible that new SCGT plants in the DEC system will not maintain high capacity factors and could be economically displaced well before the end of their lifetimes. Utility planners should weigh these risks carefully before committing to a peaking technology choice.