Abstract: A flywheel system suitable for storing energy when demand for energy from a power plant is low, and from which energy can be retrieved when energy demand increases. The flywheel includes (a) a circular composite or metallic glass ring with a radial width limited to less than about 30 percent of the ring's outer radius, and (b) at least one spoke extending along a diameter of the ring, and attached to the ring at either end. The spoke has sufficient radial extendability due to either bending and elastic radial elongation, or only elastic elongation so that, when the flywheel rotates at operating speed, the spoke extends radially to match the radial growth of the ring, without subjecting the flywheel to significant tension at points of attachment of the spoke to the ring. In one embodiment, both flywheel ring and spoke are made of oriented high strength fibers embedded in a thermoplastic resin.

Abstract: A flywheel system suitable for storing energy when demand for energy from a power plant is low, and from which energy can be retrieved when energy demand increases. The flywheel includes (a) a circular composite or metallic glass ring with a radial width limited to less than about 30 percent of the ring's outer radius, and (b) at least one spoke extending along a diameter of the ring, and attached to the ring at either end. The spoke has sufficient radial extendability due to either bending and elastic radial elongation, or only elastic elongation so that, when the flywheel rotates at operating speed, the spoke extends radially to match the radial growth of the ring, without subjecting the flywheel to significant tension at points of attachment of the spoke to the ring. In one embodiment, both flywheel ring and spoke are made of oriented high strength fibers embedded in a thermoplastic resin.