CAISO approves hybrid storage policies as California preps to add 1.5 GW by 2022
CAISO expects that storage paired with wind and solar will be a key component of the strategy to replace retiring natural gas and coal-fired generation across the West. For instance, the grid operator anticipates that the retirement of a fleet of once-through-cooled natural gas plants could lead to capacity shortfalls over the next few years — an issue that storage developers, who have filed a significant number of interconnection requests, are looking to address.
California utilities and community choice aggregators have also been investing in storage resources — PG&E, for instance, asked for regulatory approval of five lithium-ion battery projects totalling 423 MW/1,692 MWh earlier this year, while SCE in May announced that it is procuring a 770 MW/3,080 MWh package of battery resources.
Ensuring that hybrid storage resources are valued appropriately and that the grid operator has the visibility to be able to use these resources properly will be a key step towards getting to the point where they can fill the gap left by retiring natural gas resources, said Adenike Adeyeye, Western states energy manager and senior analyst with the Union of Concerned Scientists.
“Storage is really effective when it’s paired with a renewable resource like wind or solar, but then that creates that kind of mixing, where you’re trying to create rules for a resource that hasn’t really existed before,” Adeyeye explained.
Last week’s proposal is the second policy that CAISO has approved regarding different technologies located behind the same interconnection — in July, it adopted a “co-located” resource model that allowed each resource to have an individual ID and dispatch separately into the ISO market. Under the hybrid policy approved last week, the different resources will have a single ID, allowing them to be managed by the resource operator rather than the ISO.