Optimization of PV Plus Storage Peaker Plants

PV + Storage (PVS) peaker plants are increasingly considered to be viable alternatives to natural gas peakers. In order to be cost competitive, the size of the PV field and the storage capacity have to be chosen to maximize the IRR based on the PPA rate structure, which determines the value attached to the storage.

The analysis is based on an illustrative PVS plant located in the U.S. Southwest that is optimized for a PPA pricing structure from a utility solicitation.

The optimal size of the PV field in a PVS peaker is different from that of a PV-only plant, and is considered first. The optimal battery capacity to maximize IRR could be considerably less than the duration of the most preferred period of the heat map, and is considered including degradation rates. The architecture of the PVS plant is the next level of optimization. The capital cost and round-trip efficiency of a centralized architecture with AC coupling of the PV field and storage is compared with those of a distributed architecture based on DC-coupled blocks of PV and storage. 

The presentation will also include a comparison of the LCOE of the optimally sized illustrative PVS plant with a typical natural gas peaker.