Hydrostor plans two large compressed air storage facilities, one in Australia and one in California

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Toronto-based Hydrostor has a plan to build two massive long-term energy storage facilities, one near Sydney, Australia, near the site of a former mine, and another in Kern County, California, near Edwards Air Force Base. The one in Australia will be able to discharge 200 MW of electricity for up to eight hours and is expected to come online in 2027. The California facility will be able to supply 500 MW of power for eight hours and will be completed before 2030. 4,000 MWh of storage is a big number, the kind that makes people sit up and take notice, but the process is simplicity itself according to Curtis VanWalleghem, CEO and co-founder of Hydrostor.

“It's a very simple system that only uses a hole in the rock [plus] air and water,” he says Indoor climate news. “And then the equipment all comes from the oil and gas industry, so you don't need any new production or anything.” The technology actually uses some of the same techniques as pumped hydro storage. Hydrostor uses a super-sized air compressor (which would ideally run on renewable electricity) to draw in air from the environment, compress it and move it through a pipe into a cavern more than 300 meters underground. The process of compressing the air produces heat, and the system extracts that heat from the air and stores it above ground for reuse.

As the air moves underground, it moves water from the cave through a shaft to a reservoir. When it's time to release energy, the system releases water into the cave, forcing the air to the surface. The air then mixes with the stored heat that the factory has stored and this hot, dense air is passed through a turbine to make electricity.

There are no details on how the heat is stored in the ICN article. Up website, Hydrostor says: “Heat is extracted from the air and stored in its own thermal storage tank so that it can be used later in the process. Storing the heat increases efficiency and eliminates the need to use fossil fuels during discharge.” As far as we know, heat can be stored in unicorn fur. But for you skeptics out there (CleanTechnica readers tend to want more information rather than less), the company has been successfully operating a 1.75 MW proof of concept system capable of providing electricity for six hours in Canada for several years.

Hydrostor is not the only player in the long-term energy storage market, so the viability of the technology will be closely linked to how cost-effective it is compared to its competitors. The California plant is expected to cost about $1.5 billion, which would make it competitive with pumped hydro and other long-term energy storage technologies.

The Ministry of Energy says long-term storage is an essential part of a fully carbon-free electricity grid. In 2021, it set a goal to reduce the costs of the technologies needed to achieve that goal by 90 percent within ten years. VanWalleghem believes there is room to reduce costs as the company gains experience with these first few plants. The storage systems have an expected lifespan of about 50 years, which is an important data point when compared to battery systems, which have a much shorter lifespan, he says.

Yiyi Zhou, an analyst for BloombergNEF, said Hydrostor is one of about 100 companies focused, at least in part, on developing long-term energy storage. Our readers may be familiar with it ESS And Energy dome. Hydrostor stands out, she said, because the technology is “relatively mature” and the company has also been one of the most successful in the field in raising money from investors.

Hydrostor faces challenges

The proposed project in California has undergone a number of significant changes since it was first proposed. Hydrostor originally had two proposals in the state, but dropped one due to challenges in the permitting process, including some issues with building on a site overseen by the California Coastal Commission. The remaining project in Kern County also made design and site changes in response to feedback from the local community and regulators. The California Energy Commission paused its review of the Hydrostor proposal last fall to give the company time to provide more details on the updated plan. The review process started again in March and could be completed by this time next year.

The California government and the California Energy Commission have made it clear that they want to build long-term energy storage. The state has estimated that four gigawatts of energy storage capacity will be needed in the long term to meet its goal of 100 percent clean electricity by 2045. Hydrostor and government officials want to see this project get started. If that happens, it could be a showpiece to advocate for the construction of many others. “We're just looking forward to the growth of getting these projects built and then doing more, five to 10 projects at a time,” VanWalleghem said.

The takeaway

Energy storage is crucial for the transition from thermal power plants powered by coal or methane. Of course, if coal and methane didn't cause massive climate damage, no one would care. We could just run those turbines forever, or until the fuel runs out. But unfortunately the Earth is warming, leading to droughts in some areas, floods in others, and higher daytime temperatures than humans can tolerate.

The only logical response is the transition to renewable energy, which in California mainly means solar energy. But the solar energy stops working when the sun sets. Current battery energy storage systems can keep the lights on for about four hours, but after that, utilities must fall back on thermal generation, which means nuclear, coal or methane gas facilities. The more electricity that can be captured during the day and then stored for use up to eight hours later, the closer we will be to a low-emissions electricity grid.

The fact that Hydrostor relies on techniques perfected by the oil and gas industry means that a large amount of knowledge is available to quickly realize this form of energy storage. It also means that a large number of workers have already been trained in how to use the machinery needed to create a Hydrostor facility, debunking the lament that renewable energy is a threat to American jobs.

Hydrostor seems to have a good idea about how long-term energy storage can be achieved. We will monitor the company's progress in both Australia and California and keep our readers informed.