Despite the sharp U-turn in federal energy policy last year, renewable energy continues to rise in the US, particularly in the area of solar power. That helps explain why competition for space in the energy storage industry continues to heat up. Among other recent developments comes word of new activity in the ancient field of flywheels. Yes, flywheels. Initially deployed by potters as far back as 6,000 BC, flywheels are fixtures in aerospace and automotive applications among others, and now they have emerged to support the wind and solar industries. The Long Duration Energy Storage Race Heats Up Flywheels are marking out space in the somewhat rarified world of long duration energy storage. Going by a benchmark set by the US Department of Energy, that means a capacity of at least 10 hours, though ideally long duration technology can stretch into multiple days and longer. To date, pumped hydropower has provided the largest source of utility-scale, long duration energy storage in the US by far, claiming about 95% of the market. With support — somewhat weirdly — from US President Donald Trump’s “American Energy Dominance” policy, pumped storage will almost certainly continue to dominate on a capacity basis. Availability, though, is another question entirely. Pumped storage is an expensive, infrastructure-dependent venture limited by the requisite resources, namely water and elevation. New developments in the field will eventually extend the availability of pumped storage (here’s an example, and here’s another one). However, for the time being the limitations apply, leaving plenty of room for alternative technologies to fill the gap. Within that space, there is also room for flywheels. Lithium-ion battery technology has been improving, but not to the extent that it can compete in the long duration market. Other non-battery, long duration alternatives have been emerging, particularly in the thermal field where excess electricity can be deployed to heat specialized bricks or modules. Compressed air storage is another technology to gain currency in recent years. So far, though, scale-up has been slow, leaving an opening for other new systems including flywheels (see more flywheel background here). The Qnetic Advantage The latest news in the flywheel space comes from the startup Qnetic. The company, which has headquarters in the US and China, is currently aiming at the market for up to 12 hours of energy storage. The plan is to manufacture the company’s forthcoming Pulsar system in the US, though the company is currently building a testing facility in China, which it is billing as “the world’s largest dedicated flywheel test cell.” “The purpose-built test facility, located at Qnetic’s Technology Center in Shanghai, represents a million-dollar-plus investment that will serve as the company’s primary site for validating the performance, safety, and reliability of its next-generation flywheel systems,” Qnetic explains. So far, all is going according to plan. Earlier this month, Qnetic reported that excavation and foundation work at the site is well under way, while work is progressing on a 200 kilowatt-hour Pulsar prototype. Qnetic expects Pulsar to deliver long duration energy storage at a lifecycle cost lower than lithium-ion technology, while also shaving fire risk down to a minimum and reducing, if not eliminating, supply chain risks related to critical materials. “Unlike batteries, which store energy chemically, flywheels store energy kinetically by spinning a rotor at extremely high speed inside a vacuum enclosure,” Qnetic explains. “When electricity is needed, the rotating mass drives a generator to return energy to the grid. Because the process involves no electrochemical reactions, flywheel systems can deliver decades of high-performance operation while offering rapid response,” the company elaborates. Follow The Money As for what, exactly, can be expected of the new energy storage system, the company states that a Qnetic project “offers the potential to generate 2X the revenue of an equivalent lithium system, every single day.” That remains to be seen, but Qnetic also notes that its pre-market regimen includes validation by the independent, global-facing, California-based organization EPRI (Electric Power Research Institute). In a technology brief posted last October, EPRI described how Qnetic expects to distinguish itself from other competitors in the flywheel field (break added for readability): “Qnetic Corporation is developing a flywheel energy storage technology that uses a spinning rotor to store kinetic energy. Qnetic’s system uses a 15-foot (4.5m) tall high-speed rotor made from carbon fiber to improve the energy density of the system compared to a lower-speed, heavier rotor. “This rotor is held in a vacuum and is magnetically levitated by repulsive permanent magnets to eliminate wear and mechanical friction losses, which is a key weakness of current flywheel technologies.” “Qnetic is planning to first go to market with a 500kWh unit, followed by a unit that stores 1,000kWh of energy to be discharged over 4–12 hours with an 85% round-trip efficiency,” EPRI adds. That rundown apparently rang some bells within the investor community. In March of this year, Qnetic announced that it raised $7.1 million in a 12-month period, including a $5 million funding round this year and a $2.1 million equity crowdfunding campaign last year. The funds are earmarked for Qnetic’s forthcoming California factory, beginning with low-volume production of its Q500 energy storage system. Qnetic also too note of its validation agreement with EPRI, and the company referenced another validation agreement, with the US Department of Energy lab formerly known as the National Renewable Energy Laboratory. The NREL connection is of interest considering that the lab produced a report in 2021 exploring some of the assumptions, limitations, and opportunities in the area of hybrid storage systems, including mechanical technologies. More recently, the Energy Department’s Pacific Northwest National Laboratory zeroed in on the potential for lithium-ion batteries to enhance revenue from hydropower systems, with positive results for short-duration batteries of just two hours. Of interest in that regard, the US flywheel startup Torus is already working on a flywheel-battery combo. PNNL’s award-winning flywheel program could also come into play, so keep an eye out for flywheel-enhanced hydropower to make an appearance somewhere down the line. Photo: New flywheel energy storage systems can be located largely underground, offering aesthetic benefits alongside the potential for lower costs, longer duration, and less reliance on overseas supply chains (courtesy of Qnetic).
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