Long-duration storage occupies an enviable position in the cleantech hype cycle. Its allure has proven more durable than energy blockchain, and its commercialization is further along than super-buzzy green hydrogen.
Depending on who you talk to, long-duration storage technology can knock out coal and gas peaker plants, turn renewables into round-the-clock resources and generally pave the way for a carbon-free grid.
But beyond the high-level predictions, it’s hard to find a consistent definition of what this category actually means and exactly what it’s supposed to do. That’s largely because a market for such things hasn’t really existed.
That’s starting to change. On October 15, a coalition of community-choice aggregators in California released the first major request for proposals targeting long-duration projects. To qualify, plants must be:
50 megawatts or greater:
- Able to discharge electrons at that level for eight hours or more
- In operation by 2026
- Companies interested in this process cover a range of technologies, including pumped hydro, gravity-based, compressed air and flow batteries, as well as current market leader lithium-ion batteries.
GTM previously covered the main technologies vying for this emerging grid role and recently published an explainer on green hydrogen, another long-duration contender. In light of the new effort to actually buy some of this stuff, GTM has compiled a guide to why it matters, what products and companies are competing to supply it, and what hurdles this category faces.