As California moves aggressively toward its clean energy goals, the state's grid operators are considering the additional tools and compensation mechanisms they need to better integrate long-duration energy storage resources into the grid.
About 3,100MW of energy storage is currently deployed on the California grid, compared with just 1,500MW last year, the energy storage arm of the California Independent System Operator said at a seminar hosted by the California Energy Commission (CEC).
Almost all of these energy storage systems are lithium-ion battery energy storage systems. But while lithium-ion battery storage systems, typically 4 hours in duration, have been shown to only be used for short-term use, the state is also looking for longer-duration options that can provide a duration of eight hours or more.
The need to explore and pursue alternatives to lithium-ion battery energy storage systems is particularly acute as the U.S. faces broader supply chain constraints and other states and territories pursue their own clean energy goals and demand for batteries is growing.
In mid-2021, the California Public Utilities Commission required the state's power providers to source 11.5GW of clean energy, including 1GW of long-duration energy storage, to come online by 2026. As well as the state's proposed 2022-23 budget allocation of $380 million to advance the commercialization of non-lithium-ion battery energy storage systems and long-duration energy storage technology, which is administered by the California Energy Commission (CEC).
"This requirement is not technology-specific - many different technologies can meet this requirement as long as the energy storage system is continuously discharged for more than 8 hours," the president of the California Public Utilities Commission (CPUC) said at the seminar.
In the long term, the challenges facing the California power system will shift from higher summer loads to unfavorable winter weather conditions.
The current day-ahead market for California Independent System Operators (CAISOs) is primarily focused on energy storage systems with a duration of less than 24 hours. When it comes to integrating longer-duration energy storage systems that last longer, grid operators are considering the additional tools needed to ensure these resources remain charged for extended periods of time, possibly days.
Additionally, the California Independent System Operator (CAISO) is considering how to compensate long-duration energy storage resources. Long-duration energy storage technology developers have been approaching grid operators, concerned about current market demand, and don't know how to recoup their costs, except simply by paying for resource adequacy, Murtaugh said.
The policy director of the California Energy Storage Coalition said it’s important that California starts to act now to be able to bring long-duration energy storage resources to work when needed. "If we also want to achieve the long-term goals of 2035 and 2045, we have to really position the long-duration energy storage systems so that they are also ready for large-scale deployment and ready for scale-up," he said. "
