A Utah startup offers a novel energy storage system based on the rotation of a heavy steel wheel

This story is part of the Salt Lake Tribune’s ongoing commitment to finding solutions to Utah’s biggest challenges through the work of the Innovation Lab.

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The principle is simple enough. Spin a heavy wheel and momentum keeps it spinning.

But is this really a practical way to store electricity?

For a Utah startup, the answer is a resounding yes. A former EMT entrepreneur started an energy storage company based on this simple principle.

It’s called “flywheel energy storage,” and Nate Walkingshaw has tapped into it during the pandemic when he was looking for solutions to cut the cost of pumping well water to a family tree farm on the edge of Dimple Dell Park in Sandy.

He had installed a water turbine that generated electricity from running water. “However, I have found that although I can generate electricity, I cannot store it. So I started researching batteries and eventually ended up with flywheel energy storage.”

Three years later, he’s running a company, Torus, that plans to sell 150 flywheel power systems in Utah this year, and has ambitious expansion plans for years to come.

“Flywheel energy storage offers a very practical and efficient alternative to chemical batteries with longer life, better temperature resistance, no storage leakage, better recyclability and faster discharge and charge rates,” said Walkingshaw.

Torus sells package systems to homeowners that include solar panels that can provide electricity to drive a steel wheel while also powering a home during the day. When the sun goes down or a storm cuts out the power, the spinning wheel can generate electricity for hours.

The first flywheel units – measuring approximately 1.2m high, 1.2m in diameter and weighing approximately 900kg – will be built at the company’s research and development facilities in Springville. Expansion plans include the construction of a larger production facility. They also plan to build larger sizes for commercial and utility applications.

Torus is one of the few flywheel storage companies to emerge in recent years, and they say flywheels can compete with the cost of battery storage over a 25-year lifespan. Walkingshaw recognizes the pioneering role of California-based Amber Kinetics.

“Yes, we believe we are cost competitive,” Walkingshaw said. “Our prices range from $38,000 to $55,000 including solar installation. We focus on affordability and aim to offset 60-80% of our customers’ electricity costs and carbon emissions.”

The wheel stands like an air conditioning compressor in a sealed container outside the building. A vacuum pump sucks out the air surrounding the wheel to reduce friction and uses magnets to levitate the wheel so the bearings only support about 150 pounds of the 1,700-pound wheel. When covered, it makes about the same noise as an air conditioner.

These improvements are enough to keep the wheel going for days. Walkingshaw says they can currently get power for 56 hours after installation and they are working to extend that.

One of the main reasons he chose lithium battery flywheels is that batteries are affected by temperature. “The batteries would ‘wear out’ or become unusable due to the cold temperatures,” he said.

Walkingshaw knew this from his EMT days, when battery-powered wheelchairs gave out in the cold.

As a paramedic, Walkingshaw developed his first commercial success: a lightweight, portable medical sled for evacuating patients up stairs. Dubbed the “Paraslyde,” the invention was later sold to Stryker Medical. He later founded a product development company called Brightface, followed by product development stints at Tanner Labs and Pluralsight, where he was Chief Experience Officer.

He also co-wrote a book on product development, Product Leadership: How Top Product Managers Launch Awesome Products and Build Successful Teams, with several co-authors.

The product is now more than a spinning wheel and the solar panels that power it. It is also about integrating these to minimize dependency on the electricity grid. The system can even use weather forecast information to predict and maximize future usage, said Rohini Ramegowda, a Torus firmware engineer.

To highlight the integration, Torus includes an app that reports in real time where the home’s power is coming from – from the solar panels, the flywheel or the grid.

“We’ve found our app to be very effective at showing people the impact their own homes can have,” said Walkingshaw. “That’s probably the most emotional thing we talk about at our company, the stories that come back to our team and say, ‘This has completely changed the lives of my family and my children.'”

“It’s all about the user experience,” said Torus customer Daniel Eichner. “You can monitor how much carbon you’re producing and when you’re using it.”

The system makes him more conscientious about using clean electricity when it’s available. He used to do his laundry and charge his electric car at night when it was plugged in. Now he does these things during the day when the solar panels are producing.

Eichner said the flywheel was in his garage and he could hear it humming when he was in the garage. “I can’t hear anything from the house.”

Another benefit of flywheels is their ability to rapidly deploy stored energy. That makes it an attractive application for fast-charging electric vehicles. “When you need to quickly charge a vehicle from DC to DC, flywheels are an excellent choice,” Walkingshaw said.

A customer might be the Utah Department of Transportation. Lyle McMillan, director of strategic investments at UDOT, is working on expanding the state’s network of electric vehicle charging stations.

“Utah is blessed with high and low temperatures. Batteries don’t perform well at these extremes,” said McMillan, who said he’s had discussions with Torus representatives about powering remote charging stations without grid access.

Torus is a privately held company employing 65 people and Walkingshaw aims to be profitable by next year.

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