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Hybrid Plants, Particularly Solar Paired With Storage, are Seeing Strong Growth

There has been a surge in interest in hybrid power plants, particularly solar photovoltaic plants paired with battery storage, according to Lawrence Berkeley National Laboratory.

At the end of 2022, there were 374 hybrid plants larger than 1 megawatt in operation in the U.S., a 25 percent increase compared with the end of 2021, according to a Berkeley Lab briefing.

In aggregate, those plants comprised 41 gigawatts of generating capacity – a 15 percent increase from the previous year – and 5.4 GW/15.2 gigawatt hours of energy storage, representing 69 percent and 88 percent increases from year-end 2021, respectively.

The surge is being driven by improving battery technology and the growth of variable renewable generation, the Berkeley researchers said.

Photovoltaic-plus-storage was the dominant form of hybrid plant operating at the end of 2022 in terms of number of plants, 213; storage capacity, 4 GW/12.5 GWh; storage to generator capacity ratio, 49 percent; and storage duration, 3.1 hours, according to the briefing.

As a result of the growth of PV-plus-storage plants, there was roughly as much storage capacity operating within PV-plus-storage hybrid plants at the end of 2022 as in standalone storage plants, the Berkeley researchers noted, adding that in terms of energy, PV-plus-storage plants edged out standalone storage by about 2 GWh.

The researchers noted, however, that there are also nearly 20 other hybrid plant configurations, including several fossil hybrid categories, as well as wind-plus-storage, wind-plus-PV, wind-plus-PV-plus-storage, and geothermal-plus-PV.

The momentum of PV-plus-storage plants was also evident in that last year 59 of the 62 hybrids added combined PV with storage, the briefing said.

In addition, interconnection queue data shows “continued strong developer interest in hybridization,” the researchers said in the briefing. At the close of 2022, there were 51 percent more hybrid plants, representing 59 percent more generating capacity, in interconnection queues across the United States than there were at the end of 2021.

Solar power also dominates proposed plants, the briefing noted. At the close of 2022, there were 457 GW of solar capacity proposed as a hybrid, representing about 48 percent of all solar capacity in the queues, most typically pairing PV with battery storage.

There were also 24 GW of wind capacity proposed as a hybrid, mostly paired with storage, representing about 8 percent of all wind capacity in the queues. And more than half of all storage in the queues is estimated to be part of a hybrid plant.

The growth of PV-plus-storage plants is particularly notable in some regions, the researchers said, citing the California Independent System Operator region where 97 percent of all solar capacity and 45 percent of all wind capacity in the queues is proposed as a hybrid plant.

Berkeley Lab’s briefing is updated annually and tracks existing hybrid or co-located plants across the United States by synthesizing data from power purchase agreements and generation interconnection queues. The briefing collects data on hybrid plants with 1 MW or more of capacity. Smaller projects, often behind-the-meter, are increasingly common, the researchers said, but are not included in the briefing data.