Shaft-less, Hub-less High Strength Steel Flywheel

Flywheels are being implemented for frequency regulation by electric utilities but are suitable in a broader role of energy storage for greater effectiveness and acceptance of renewable energy sources such as wind and solar. Increasing energy density is key to expanding the flywheels role in these areas. The proposed work will accomplish this goal via development and commercialization of a unique high strength steel flywheel design that provides mass based energy density competitive with composite flywheels and volume based energy density 3 to 4 times higher, while utilizing a more reliable material, being extensively characterized and documented in the open literature. This advance results from utilizing a shaft-less, solid wheel, to continuously vary the motor/generator gain achieves greater depths of discharge and shorter charge times. Phase I yielded (a) the building of a 4 kw-hr concept demonstrator flywheel, (b) a completed magnetic suspension proof of concept test rig for the flywheel, and (c) analysis and conceptual design of a 100kw-hr flywheel system.Phase II will yield (a) full speed testing of the complete 4kw-hr flywheel, (b) detailed design of a 100kw-hr flywheel to suit commercial applications, and (c) fabrication and testing of the 100kw-hr flywheel to validate performance for commercial applications.: if Phase II is awarded, future applications include (i) Frequency regulation at electric utilities, (ii) energy storage during curtailment periods at wind and solar farms, (iii) boost power source for high speed rail systems, (iv) regenerative braking for buses, trains, cranes, drillstrings, etc.