The Story of Hydrostor: The Company Building Underground Batteries for the Renewable Future

Sometimes, the biggest innovations start with the smallest irritations. For Curtis VanWallenghem, it began with a nuclear plant that couldn’t adapt to wind power. In a recent episode of Category Visionaries, the Hydrostor CEO shared how this operational headache led to a revolutionary approach to energy storage that could help solve one of renewable energy’s biggest challenges.

A Nuclear Problem Sparks an Innovation

While working at an electrical utility, Curtis faced an unexpected challenge. Their nuclear plant wasn’t designed to adjust its output based on wind conditions. “We had to start turning it up and down depending on how windy it was,” Curtis explains. “The maintenance team came and said, our budgets are going up, the reactor is not meant to operate this way.”

The obvious solution was energy storage – but existing options fell short. Pumped hydro facilities were nearly impossible to permit, and batteries were prohibitively expensive. Then, an analyst showed Curtis a patent that would change everything.

From Patent to Prototype

The patent described a new way of doing compressed air energy storage. As Curtis explains, “What we’ve done is we’ve made an air battery where we dig a hole in a bedrock about 2000ft underground.” This cavern, roughly the size of “a couple cubic football fields,” becomes the heart of their storage system.

The concept was elegantly simple: use excess renewable energy to compress air into the cavern, displacing water to a surface reservoir. When power is needed, release the water, using its weight to force the compressed air through turbines. The result? “An air rock and water battery that lasts 100 years and is really cheap to build compared to batteries.”

The Personal Mission Behind the Technology

But this wasn’t just about solving a technical problem. For Curtis, the motivation ran deeper. Looking at his niece Shay, he realized, “This is our generation’s world war, this climate change… When Shay grows up and the world’s burning, she’s like, ‘what did you do about it?’ And I said, ‘nothing. I just watched it burn and made some money and made myself comfortable.'”

This personal connection to the climate crisis drove Curtis to persist through countless challenges, including several near-death moments for the company.

Surviving the Dark Times

The journey wasn’t easy. When COVID hit, Curtis recalls, “We only had six or seven weeks of cash left. And then COVID hit and every investor just said, I’m not getting involved or I’m not making commitments until we know where it’s happening in the world.”

The solution? “Me and a bunch of others mortgaged homes and put more money in to get the company to survive.” Then came another challenge – their first major contract was in Australia, but the borders were closed. They had to frantically secure a joint venture partner to move forward.

Building for the Future

Today, Hydrostor stands at a turning point. Their three-year vision, as Curtis outlines, is to “get our first big plant running and have a couple more under construction and another ten contracted.” Once these milestones are achieved, “the machine almost will run itself because there’s construction companies out there that do this.”

But the implications go far beyond business success. “Every time we contract a plant,” Curtis explains, “you’re shutting down a giant coal plant or a gas plant and you’re enabling a whole bunch of wind and solar.”

This is the future Hydrostor is building – one where renewable energy can power our grid reliably, regardless of when the wind blows or the sun shines. It’s a future where Curtis can tell his niece Shay that when the world needed solutions, he didn’t just watch it burn – he helped build something that could make a difference.

As Curtis reflects on the journey, he notes, “I am proud and happy we’ve kind of made it to this point, but boy, it was a lot harder than what I was expecting. It took a lot longer.” But then again, maybe that’s what it takes to build something that could help change the world.