By Christian Roselund

A new briefing by Lawrence Berkeley National Laboratory (LBNL) has documented the increasing popularity of hybrid solar and energy storage plants, finding that most of the grid-scale (1 megawatt and larger) batteries that have been installed in the United States to date are paired with solar PV. The briefing found 7 gigawatt-hours of hybrid plants versus 3.5 gigawatt-hours of standalone batteries, including several large solar projects that have been retrofitted with batteries.

LBNL found that wind plants are far less frequently paired with energy storage and that wind plus storage plants were more often used for grid services. By contrast, solar plus storage projects are increasingly charging during periods of low power prices and discharging during periods of high prices. This is particularly true in California and other regions where high penetrations of solar drive down mid-day power prices. The largest number of solar plus storage projects were found in Massachusetts, where 49 of 54 PV plants 1 megawatt and larger were solar plus storage. However, by far the largest capacity of solar plus storage was in California, as the individual systems were much larger.

LBNL also found that while solar plus storage power contract prices have been on a downward trend over the last seven years, the price per megawatt-hour of the battery portion of contracts has been increasing since 2020. Prices for solar plus storage contracts remain much higher in Hawaii than in the rest of the country. LBNL’s review of interconnection data at the grid operator level suggests that the trend of combining energy storage and solar will continue as more projects come online. The report found that 42% of the capacity of solar projects currently proposed is in projects paired with energy storage. This varies widely by region, from a low of 6% in New York to a high of 95% in California.

Source: Hybrid Power Plants: Status of Operating and Proposed Plants, 2022 Edition (LBNL)