Unbeknownst to many, flywheel-battery combinations offer a hidden edge in grid stability, making them a hidden gem in the power grid's arsenal.
In a groundbreaking development, a hybrid system at Waterford School in Sandy, Utah, is harnessing the power of 45 on-site geothermal wells, coupled with a flywheel and battery array, to smooth electrical load fluctuations and provide backup power. This innovative approach to energy storage is proving to be a game-changer in the face of growing demand from AI data centers and electric vehicle (EV) fast-charging stations, which are overwhelming traditional planning models.
The Benefits of Hybrid Flywheel-Battery Systems
Hybrid flywheel-battery storage systems offer significant benefits for grid stability and distributed energy resources by combining the strengths of both technologies. Flywheels provide fast, clean ride-through power and effectively absorb sharp demand spikes or rapid fluctuations due to their mechanical durability and rapid response. Batteries complement this by sustaining power output for longer durations, supporting load shifting and outages that exceed the flywheel’s short discharge period.
Grid Stability and Frequency Regulation
Flywheels contribute inertia support and quick frequency regulation thanks to their kinetic energy storage, helping counteract grid instabilities and voltage/frequency oscillations that can cause outages.
Handling Demand Spikes in High-Stress Environments
In high-stress environments such as AI data centers and EV fast-charging stations—both with high peak loads and sensitive power quality requirements—flywheels smooth sharp demand spikes, while batteries provide sustained energy delivery to multiple loads.
Extended Life and Reduced Cost of Battery Systems
By handling high-cycling stress with flywheels, battery degradation is reduced, extending battery life from typical 8–10 years to 15–20 years, lowering the total cost of ownership despite a higher initial investment.
Avoiding Costly Grid Upgrades
Hybrid systems provide localized, intelligent energy storage from the grid edge, reducing the need for infrastructure expansion and allowing existing grid assets to operate closer to capacity safely.
Flexible Hybrid Solutions Integrating with Other Grid Stability Technologies
Combined with synchronous condensers and inverter-based controls, hybrid systems can provide inertia, reactive power support, short-circuit power, and ancillary grid services with intelligent management, as demonstrated by experimental plants in the UK and Ireland.
Suitability for Distributed Energy Resources
Hybrid systems support distributed energy generation by offering fast response and high efficiency in power conversion, enabling smooth integration with renewables and enhancing power quality and reliability at the local level.
Real-World Applications
The hybrid flywheel-battery system at Waterford School serves as a model for distributed infrastructure that delivers speed, resilience, and real value to utilities and commercial operators. Commercial hybrid projects are operating, and domestic manufacturing is scaling, making this technology a viable solution for a more stable and efficient grid.
As the U.S. grid faces a staggering $1.1 trillion in capital needs over the next decade, hybrid systems can help avoid costly grid upgrades, making them a crucial component in the transition to a cleaner, more distributed power system. The proliferation of energy storage in everything from utility-scale batteries to electric vehicles is driving this transition, and hybrid systems are at the forefront of this revolution.
Domestic Manufacturing and Recyclability
New American-made LFP cells are engineered for demanding grid applications, built domestically, and designed for recyclability. These cells are unmatched for fast response and power quality, while batteries excel at energy storage but are poorly suited for high-frequency power management. Together, batteries and flywheels create a storage platform that gets stronger under stress, not weaker.
Over 20 years, hybrid systems deliver a lower total cost of ownership with no degradation, no replacements, and minimal maintenance. With domestic manufacturing becoming competitive and new American-made LFP cells delivering 3-6C performance that rivals the world's best, the future of hybrid flywheel-battery storage systems looks bright.
In conclusion, the grid America needs will depend on systems that combine mechanical durability, chemical efficiency, and intelligent control from the edge of the grid to the core. Hybrid systems solve challenges that single-technology approaches can't, as batteries alone degrade under high-cycling stress and flywheels alone don't provide enough stored energy. Utilities' traditional reliance on large power plants is shifting to a model that includes distributed energy resources such as rooftop solar, battery storage, and electric vehicles. The hybrid flywheel-battery system at Waterford School is a shining example of this new paradigm, providing speed, resilience, and real value to utilities and commercial operators.
- The integration of renewable-energy sources with hybrid flywheel-battery systems is essential for a more stable and efficient grid, especially in high-stress environments like AI data centers and EV fast-charging stations.
- The previous text mentions the total cost of ownership being lowered with hybrid systems, as they extend battery life, reduce the need for infrastructure expansion, and make use of domestic manufacturing and recyclable LFP cells.
- Technology advancements in data-and-cloud-computing and electric vehicles, along with the growing demand for AI data centers and EV fast-charging stations, are driving the transition to a cleaner, more distributed power system, and hybrid systems are leading this revolution.
