Abstract
Hundreds of gigawatts of renewable technologies, such as wind and solar, need to be installed to reach a zero-carbon electricity system that meets current and future energy needs. Locations of new installations are typically chosen based on wind and solar availability to maximize facilities' capacity factors. Here, we show that this is not always true in least-cost models, and optimal siting depends also on the flexibility of the electricity system. To show this, we use a macro-scale energy model to evaluate capacities and dispatch in least-cost electricity systems with distributed wind and solar generation supported by battery storage. If battery storage were free and widely available, chosen locations for wind and solar installations would inevitably be in regions with the highest wind and solar capacity factors. However, as the battery storage cost increases and thus storage capacity decreases, chosen locations have lower capacity factors and the electricity system is more reliant on wind generation. In the case of a system without energy storage, only wind generation would in fact meet certain periods of electricity demand. This study suggests that current optimal wind and solar siting may no longer be the least-cost solution as the storage cost decreases.