Abstract

Pacific Gas and Electric Company’s (PG&E) advanced underground, compressed air energy storage (CAES) demonstration project is intended to validate the design, performance, and reliability of a CAES plant rated at approximately 300MW with up to 10 hours of storage. The CAES demonstration project is scoped to test the suitability of a porous rock formation as the storage reservoir in California, and demonstrate the technological improvements in the design of such plants. Porous rock formations are much more plentiful than the salt domes now used by the two operational plants in Alabama and Germany. If this geology is proven viable, this technology has the potential to be replicated throughout California and elsewhere in the United States. The project is also differentiated by its potential use of a new CAES plant design that is much more efficient than first generation Alabama and German designs. This project is comprised of three phases. Phase I includes site selection, reservoir testing, preliminary plant design, permit preparation and a competitive solicitation for plant construction and ownership. Phase I has an estimated 4.5 year duration. Phase II, which includes obtaining approval to proceed with the construction and commissioning of a full CAES plant, has an estimated 6 year duration, and Phase III includes operations & monitoring and has a 2 year duration.