Proven Tech and Local Labor Are Leading a Long Duration Energy Storage Buildout

The technologies that have begun to define our era are also set to cause a spike in the world’s demand for energy. The growth of smart technology in our homes and businesses will require a huge amount of electricity, and the data centers that power the AI ambitions of modern technology are notorious for their hunger for energy. It is clear that the world’s power grid must grow and modernize to accommodate what’s coming. However, as Hydrostor President Jon Norman points out, this modernization needed to happen no matter what.

“The conventional grid is reaching the end of life,” he says. “The last investment cycles on the grid were really 30-40 years ago. What’s interesting about what’s happening now is that there was always going to be a need to modernize around this time period — regardless of the decarbonization agenda.”

It’s true that the ongoing growth of renewable resources like solar and wind are key to modernizing the grid, not only because they provide clean energy and energy security, but also because, as Norman notes, they are now among the least-expensive ways to add new electricity onto the network. Alongside them, the modern grid needs more ways to store energy, which would allow us to save sun power for the nighttime, for example, or stash away energy to avoid blackouts. But while lithium-ion batteries and pumped hydro systems have begun to fill some of that short-term storage need, Hydrostor’s technology provides the opportunity to do something more: to store a large quantity of megawatts for many hours or days at a time, an ability that would modernize the power grid in a variety of ways, supporting the energy demands of tomorrow and easing grid congestion to make way for continued economic growth.

Hydrostor’s advanced compressed-air energy storage (A-CAES) technology uses the elemental forces of water, air, and gravity to store grid energy for long durations with minimal losses. Picture a purpose-built underground cavern filled with water, and an empty reservoir situated aboveground. Hydrostor facilities use grid electricity to compress air, which it sends below ground, capturing the heat created during the process. The pressurized air then pushes the water from the underground cavern into the aboveground pond (a closed-loop reservoir). In this state, the big underground battery is “charged.” When the stored energy is needed, water is released from the reservoir and flows into the cavern, pushing the compressed air back out to the surface. There, after being recombined with heat, it moves through turbines to create electricity.

One Hydrostor A-CAES facility can store 500 megawatts of energy and deploy it whenever necessary. In this way, it can act as a traditional energy-generating plant. “Say there’s a power plant retiring,” Norman says. “We can surgically locate in a grid where the new project provides that same benefit and the same type of synchronous inertia that traditional power plants provide” — that is, the grid’s ability to constantly match electricity demand in real time. “It’s just using off-peak electricity almost in a way that provides that capacity on the grid.”

Hydrostor’s facilities can also take the place of transmission line expansion. At one proposed project site in Australia, Hydrostor’s system provides the backbone of a mini grid by storing solar and wind generation and providing it as a backup solution for the town when the single transmission line that reaches to the remote region goes down. (The last time that this happened, the region was without power for days.)

This Australian use case demonstrates how longer-term storage will be a critical piece of modernization. Lithium-ion batteries, like those inside our EVs and smartphones, have already begun to buttress the grid with extra storage capacity. But they are most useful for storing energy for short periods up to 4 hours, and they suffer from long-term performance degradation the same way a phone’s battery life fades over time. Pumped hydro systems are a useful tool but can be located only in specialized locations and can be difficult to successfully permit.

Hydrostor’s flexibility is its strength. Rather than inventing exotic new technologies, the system uses an established supply chain. For example, the turbines, compressors, and other equipment are already proven in the oil and gas industry, while the excavation of caverns is borrowed from techniques already used for underground hydrocarbon storage. Because of the relatively simple requirements, a Hydrostor A-CAES facility can be cited in many different locations; Norman estimates that between a third and a half of a given power jurisdiction would typically work. And Hydrostor is dense and efficient with space: A 500-MW facility occupies only 100 acres, compared with the more than 800 acres needed for an average 1,000-MW nuclear power facility in the United States.

Although it occupies relatively little above-ground space, a Hydrostor facility is a major infrastructure project — which means that it doubles as a robust engine of job growth for the area, one that builds upon the skill sets already present in the local community. “We have hundreds of people working on-site at any one time during a four- to five-year construction period,” Norman says. “And the skill sets that are required to operate the plant are the same skill sets as operators that run fossil plants. It’s not like you’re retraining people to clean solar panels. This is literally the same job dropped onto the site: high-paid, very skilled jobs, and a direct translation of what they have done before.”

The Willow Rock project underway in Kern County, California, for example, will employ more than 6,500 people throughout the course of construction. Once complete, the facility will provide 40 full-time jobs during its 50-plus year operational lifetime. While a 500-megawatt A-CAES project costs roughly $1.5 billion, more than a third of the capital expenditure for the project goes to the cost of building the underground cavern with on-site mining labor. Together with the onsite labor needed to integrate the aboveground equipment with the underground development and build the necessary transmission infrastructure, this means that a significant percentage of the money for Hydrostor projects goes to paychecks for American workers.

Even in a time of clear partisan divisions over what kinds of energy will power the economy, Norman points out, there is widespread agreement that energy storage is crucial to powering the grid modernization that America so urgently needs. Sun-drenched areas of the American Southwest like Arizona and New Mexico, as well as wind energy powerhouse areas like Wyoming and Colorado, are beginning to ask for more long-term storage capabilities to help them manage times when solar or wind energy go through inevitable dips.

Utilities, Norman says, have begun to recognize that they need energy storage of 8 to 10 hours, and preferably longer, to make sure they can replace their solar and wind capacity when those intermittent resources are producing less energy than average. “If you have a storage resource that can provide that amount, then you’re going to be able to fill that gap,” he says. “And that’s what is really significantly driving those needs.”

And if we are to move away from keeping aging assets online to meet our energy needs — which costs ratepayers millions of extra dollars — then it is essential for utilities to embrace modern, longer-term storage solutions like Hydrostor’s plants.

The grid, after all, needs to meet demand with supply every second, but has never before been able to reliably store large amounts of electricity. Under the old way of doing things, the best we could do was to instantaneously tap into the energy that’s stored within fossil fuels. “Think about natural gas or coal,” Norman says. “It’s kind of like stored energy. You just burn it and then, boom, you have your electricity product. If those things are retiring, you really need longer-term storage on the grid.”