VanWalleghem said there is room to reduce costs as the company gains experience in these first plants. The storage systems have a projected lifespan of about 50 years, which is important when compared to battery systems, which have much shorter lives, he said.
Yiyi Zhou, an analyst at BloombergNEF, said Hydrostor is one of about 100 companies that are focused, at least in part, on developing long-duration energy storage.
Hydrostor stands out, he said, because its technology is “relatively mature” and the company has also been one of the most successful in the sector in raising money from investors.
BloombergNEF reported a global total of 1.4 gigawatts and 8.2 gigawatt-hours of long-duration energy storage as of last September, excluding pumped hydropower. The average duration, which can be calculated by dividing gigawatt-hours by gigawatts, was 5.9 hours.
For perspective, the two Hydrostor projects being developed have a combined capacity of 0.9 gigawatts, more than half of the global total currently online.
For this year and next, the long-duration storage technologies that are likely to see the fastest adoption are compressed air storage and flow batteries, according to BloombergNEF. (I wrote an explanation about flow batteries in 2022.)
I find it difficult to cover this part of the clean energy economy because of the large gap between what has been developed and what is in some planning stage. There are many opportunities for projects to fail and die along the way.
With this in mind, I will be watching to see if Hydrostor can begin construction as planned in Australia and if it can get through the regulatory approval process for the plant in California.
The California project has gone through big changes. At one point, Hydrostor had two proposals in the state, but abandoned one due to challenges in the permitting process, including some issues with construction on a site overseen by the California Coastal Commission. The remaining project, Willow Rock, also underwent design and location changes in response to feedback from the local community and regulators.
The California Energy Commission paused its review of Willow Rock last fall to give Hydrostor time to provide details on its updated plan. The review process began again in March and could be completed this time next year.
One of the factors to consider is that the California state government and the California Energy Commission have made it clear that they want to build long-duration energy storage. The state has estimated it will need 4 gigawatts of long-term energy storage capacity to meet the goal of 100 percent clean electricity by 2045.
Hydrostor and state officials want this project to get underway. If that happens, it could provide a masterpiece that justifies the construction of many others.
“We’re looking forward to growth, just building these projects and then starting to do more, five or 10 projects at a time,” VanWalleghem said.