Hybrid power plants continue to be deployed across the U.S., with almost 300 such facilities (all with 1 MW or more of generation capacity) operating at the end of last year.

An August 2022 report from the Lawrence Berkeley National Laboratory in California, based on research funded by the U.S. Dept. of Energy (DOE) and its Office of Energy Efficiency and Renewable Energy, along with the Wind Energy Technologies Office and Solar Energy Technologies Office, showed there were 140 photovoltaic (PV) solar+storage plants in operation. Those plants account for 2.2 GW of energy storage capacity, and 7 GWh of storage energy, far more than any other type of hybrid configuration.

This map shows the location of hybrid power plants across the U.S. Source: Lawrence Berkeley National Laboratory, U.S. Energy Information Administration

Other types of hybrid plants include wind+storage, combinations of wind and solar, as well as wind+solar+storage. The report also notes hybrids pairing fossil fuels with hydropower, with energy storage, and with solar power.

‘Large and Growing Share of Proposed Plants’

The report said hybrid installations “comprise a large and growing share of proposed plants,” with “42% (285 GW) of all solar and 8% (19 GW) of all wind in interconnection queues … proposed as hybrids.” That compares with 34% of solar and 6% of wind installations as recently as 2020.

The Berkeley lab said 298 hybrid plants were online in the U.S. at the end of 2021. The report notes that “PV+Storage plants have more battery capacity and energy than standalone batteries,” with 400 MW more capacity and 3,500 MWh more energy. “In fact, PV+Storage has more storage energy than all other hybrid and standalone categories combined.”

Massachusetts accounts for most of the PV hybrid plants, with 54 such facilities in that state, including 49 that are solar+storage. California is second with 37 total plants, including a dozen with installed solar power generation capacity of more than 100 MW.

California also has nearly half of all fossil+storage hybrids—nine in total—while no other state has more than two.

Adding Storage to Solar

The report noted several battery energy storage systems were retrofitted to existing solar farms last year, mostly in Florida and California.

The researchers said that in a sample of solar+storage plants operating with public power purchase agreements (PPAs), the “PPA prices have declined over time. That said, levelized storage adders for PV+Battery plants on the mainland have recently increased slightly to ~$5,500/MW-month, ~$45/MWh-stored, and ~$15/MWh-PV [depending on the storage ratio].”

Darrell Proctor is a senior associate editor for POWER (@POWERmagazine).