California’s interconnection queue included 29 GW of proposed solar-plus-storage plants as of year-end 2019, while Western utilities’ queues had another 33 GW, as shown with yellow bars below (CAISO and West non-ISO).
Yet planned gas units totaled only 0.2 GW in California’s queue and 4 GW in Western utilities’ queues.
While the majority of plants proposed in the interconnection queues “are not subsequently built,” says the report, a Western trend favoring solar-plus-storage over gas units seems clear.
Solar plus 4-hour storage has been found to have a 99.8% capacity value in California, easily matching gas.
The Midwest shows signs of a similar trend, as the region’s interconnection queues (ERCOT, MISO and SPP above) had 21 GW of proposed solar-plus-storage plants at year-end 2019, well above the 13 GW of proposed gas units.
Gas is still favored in the East, as Eastern queues had 59 GW of proposed gas units at year-end 2019 (shown in blue below, counting Southeast non-ISO, PJM, NYISO, and ISO-NE), and only 13 GW of proposed solar-plus-storage plants.
Overall, 28% of solar projects in the interconnection queues include storage.