Flywheel Instead of Lithium: The U.S. Is Testing a Giant Energy Storage Technology

In the United States, an important testing phase is underway for an innovative electricity storage system that could potentially become an alternative to traditional lithium-ion batteries. Qnetic, a company based in New York, has developed a unique flywheel called Pulsar, capable of storing enormous amounts of energy. The technology is now undergoing independent evaluation as part of the deRISKED program of the Electric Power Research Institute (EPRI), funded by the Sacramento Municipal Utility District (SMUD). This assessment will include a thorough analysis of the system’s performance, safety, reliability, and readiness for large-scale commercial deployment.

Mechanical Energy Storage: How Pulsar Works

Unlike batteries that rely on chemical reactions to store energy, the Pulsar system works on a completely different principle. It stores electricity in the form of rotational kinetic energy. At the heart of the system is a high-speed composite rotor housed in a sealed vacuum enclosure. When electricity enters the system, it is used to spin the rotor up to extremely high speeds. The faster the rotor spins, the more energy it stores. When electricity is needed, the reverse process converts this stored mechanical energy back into electrical energy.

The developers explain that the charging process involves an electric motor-generator that spins up the flywheel. The stored energy is directly tied to rotational kinetic energy. The higher the rotor speed, the more energy it can hold. Discharging works in the opposite direction: the rotor gradually slows down, and its mechanical energy is converted back into electrical energy through the same motor-generator and fed into the grid.

Innovative Solutions to Minimize Losses

A key achievement by Qnetic engineers has been developing ways to minimize energy losses during the flywheel’s long-term rotation. To do this, the rotor operates in a vacuum, which virtually eliminates air resistance. In addition, the rotor shaft is supported by magnetic bearings. These bearings, developed by Qnetic, are active and can control the shaft position with minimal clearance, avoiding mechanical contact. This solution significantly reduces friction, component wear, and, as a result, energy losses. Qnetic says Pulsar is designed for decades of uninterrupted operation while maintaining high performance. The system can withstand an essentially unlimited number of charge-discharge cycles, offers instant response, and provides predictable economics throughout its service life, which is a major advantage over conventional battery systems.

Independent Evaluation to Build Consumer Trust

At present, all claimed characteristics of the Pulsar system will be carefully verified within EPRI’s standardized evaluation process. This does not rely solely on data provided by the developer, but involves a comprehensive study. Pulsar is aimed at markets where there is a need for long-duration energy storage and frequent charge-discharge cycles. Qnetic is developing Pulsar for a range of grid applications, including renewable energy integration, grid balancing, microgrids, powering industrial facilities, and energy-intensive data centers.

The deRISKED program, which stands for “Readiness Informed by Shared Knowhow, Evaluation, and Data,” was specifically created to systematically assess pre-commercial energy storage technologies. Its methodology combines laboratory testing, field demonstrations, and in-depth analysis of the resulting data.

Qnetic CEO Michael Pratt emphasized the importance of objective evidence for utilities when choosing new energy storage technologies. “Independent validation has become just as important as the technical innovation itself,” he said. “By participating in the EPRI deRISKED program and providing substantial data from the prototype and pilot system, we are giving utilities the transparency they need to evaluate our technology on its technical merits, while also helping them better understand where flywheel energy storage delivers the greatest value,” Pratt added.

The main goal of this evaluation is to provide utilities with reliable technical information that will be considered separately from the manufacturer’s marketing claims. This will allow them to make an informed decision about the possible adoption of energy storage systems. The results will be shared with all utilities participating in the deRISKED program, contributing to a broader understanding of the potential of this advanced technology.

Market Context and Future Prospects

The search for efficient and long-lasting energy storage solutions is one of the key challenges facing today’s energy sector. The growing share of renewable energy sources such as solar and wind requires reliable systems for balancing the grid and ensuring stable electricity supply. Despite their widespread use, lithium-ion batteries have certain limitations related to lifespan, cost, safety, and the environmental impact of raw material extraction.

Flywheel energy storage technologies, while not entirely new, continue to improve. Qnetic’s Pulsar system demonstrates significant progress in this field, offering the potential for long-term, cyclical energy storage. Successful completion of the independent EPRI evaluation could open the door to broader adoption of this technology across various sectors, from power grids to industrial plants and data centers, helping build a more resilient and reliable energy infrastructure for the future.