The role of conventional power plants in a grid fed mainly by PV and storage, and the largest shadow capacity requirement

Recently we reported that PV penetration of up to approximately 90% of the annual demand of the Israeli electricity grid could be achieved using properly sized storage and an appropriate operation strategy. Such a grid clearly requires some conventional generating capacity to be available in order to serve as backup at times when the PV-storage combination alone fails to meet the demand. In the present continuation of that study, we evaluate the largest conventional capacity that would have been required during the one year of data employed for our simulations. For that year, 2006, the required backup capacity for a grid with flexibility ff=0.8 and ff=1 would have been 7.5. GW and 6.6. GW, respectively. This is significantly less than the 10.5. GW of generating capacity that the Israel Electric Corporation operated that year. Our finding emphasizes the fact that a full economic optimization of storage must be based primarily on the engineering-aspects of storage design and use.