In this article there is a link to the .PDF paper with the research and technical details. The sad story of Beacon which went bankrupt a year after completing the Stephentown flywheel storage farm, still operating. Now, Amber Kinetics is making small systems.
I read about flywheel energy storage systems decades ago, the design concepts and plans have been around for a very long time.
https://h2-observer.com/2020/09/06/flywheel-energy-storage-back-to-the-future/
