This story is part of The Salt Lake Tribune’s ongoing commitment to identify solutions to Utah’s biggest challenges through the work of the Innovation Lab.
The principle is simple enough. Spin a heavy wheel, and momentum will keep it spinning.
But is that really a practical way to store power?
For one Utah startup, the answer is a resounding yes. A former EMT turned entrepreneur has launched an energy storage company based on that simple principle.
It’s called “flywheel energy storage,” and Nate Walkingshaw locked into it during the pandemic while looking for solutions to reduce the cost of pumping well water to a family tree farm at the edge of Dimple Dell Park in Sandy.
He had installed a hydroturbine that generated power from flowing water. “However, I discovered that while I could generate power, I couldn’t store it. So, I began researching batteries and ended up exploring flywheel energy storage.”
Three years later, he is running a company, Torus, that hopes to sell 150 flywheel energy systems in Utah this year, and he has aggressive expansion plans in subsequent years.
“Flywheel energy storage offers a very practical and efficient alternative to chemical batteries, with a longer lifespan, better temperature resilience, no memory loss, better recyclability, and higher discharge and charge rates,” Walkingshaw said.
Torus sells packaged systems to homeowners that include solar panels that can deliver power to spin up a steel wheel while also powering a house during the day. When the sun sets or a storm knocks out power, the spinning wheel can generate hours of power.
The first flywheel units — which are about four-feet tall, four-feet in diameter and weigh about 2,000 pounds -- are being built at the company’s R&D facilities in Springville. Expansion plans include building a larger manufacturing facility. They also plan on building larger sizes for commercial and utility-scale applications.
Torus is one of a handful of flywheel storage companies that have emerged in recent years, and they say flywheels can compete with battery storage costs over a 25-year lifetime. Walkingshaw credits California-based Amber Kinetics with leading the way.
“Yes, we believe we are cost-competitive,” Walkingshaw said. “Our pricing ranges between $38,000 and $55,000, which includes solar installation. We focus on affordability and aim to offset 60 to 80% of customers’ power costs and CO2 emissions.”
The wheel sits in a sealed container outside the building like an air conditioner compressor. A vacuum pump sucks out the air surrounding the wheel to reduce friction, and it uses magnets to levitate the wheel so the bearings only hold about 150 pounds of the 1,700-pound wheel. When covered, it makes about the same amount of noise as an air conditioner.
Those improvements are enough to keep the wheel spinning for days. Right now Walkingshaw says they still can pull power 56 hours after it was put in, and they’re working on extending that.
One of the main reasons he turned to flywheels from lithium batteries is that batteries are affected by temperature. “The batteries would “brick” or become unusable due to the cold temperatures,” he said.
That was familiar to Walkingshaw from his EMT days, when battery-powered wheelchairs would die in the cold.
It was as an EMT that Walkingshaw engineered his first commercial success: a lightweight, portable medical sled for evacuating patients down staircases. Called the “paraslyde,” the invention was later sold to Stryker Medical. He later started a product development company called Brightface, which was followed by product-development stints at Tanner Labs and Pluralsight, where he was Chief Experience Officer.
He also wrote a book about product development with a couple of co-authors called “Product Leadership: How Top Product Managers Launch Awesome Products and Build Successful Teams.”
The product now is more than a spinning wheel and the solar panels to drive it. It’s also the integration of those to minimize reliance on the grid. The system can even use weather forecasting information to predict future use and maximize for it, said Rohini Ramegowda, a Torus firmware engineer.
To emphasize the integration, Torus includes an app that gives real-time reporting of where the house’s power is coming from – the solar panels, the flywheel or the grid.
“We’ve found our app to be very successful in helping people see the impact their own home can make,” Walkingshaw said. “That’s probably the most emotional thing that we talk about at our company, the stories that come back to our team saying, ‘This has completely changed my family and my kids’ life.’”
“It’s all about user experience,” said Torus customer Daniel Eichner. “You can monitor how much carbon you’re producing and when you’re using it.”
The system has made him more conscientious about using clean power when it’s available. He used to wash clothes and charge his electric car at night when it pulls from the grid. Now he’s doing those things during the day when the solar panels are producing.
Eichner said the flywheel is in his garage, and he can hear it humming when he’s in the garage. “I hear nothing from the house.”
Another advantage of flywheels is the ability to deliver stored power quickly. That makes it an attractive application for fast-charging electric vehicles. “If you need to quickly DC-to-DC fast charge a vehicle, flywheels are an excellent choice,” Walkingshaw said.
One customer could be the Utah Department of Transportation. Lyle McMillan, UDOT’s strategic investments director, is working on building out the state’s network of electric vehicle charging stations.
“Utah is blessed with high and low temps. Batteries don’t perform well at those extremes,” said McMillan, who said he has had conversations with Torus representatives about powering remote charging stations with no grid access.
Torus is a privately held corporation with 65 employees, and Walkingshaw is aiming to be profitable by next year.
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