From “Superconductivity: Present and Future Applications” by the Coalition for the Commercial Application of Superconductors.
With power lines increasingly congested and prone to instability, strategic injection of brief bursts of real power can play a crucial role in maintaining grid reliability. Small-scale Superconducting Magnetic Energy Storage (SMES) systems, based on low-temperature superconductors, have been in use for many years. These have been applied to enhance the capacity and reliability of stability-constrained utility grids, as well as by large industrial user sites with sensitive, high-speed processes, to improve reliability and power quality.
Larger systems, and systems employing HTS, are a focus of development. Flywheels, based on frictionless superconductor bearings, can transform electric energy into kinetic energy, store the energy in a rotating flywheel, and use the rotational kinetic energy to regenerate electricity as needed. Using bulk HTS self-centering bearings allows levitation and rotation in a vacuum, thergy reducing friction losses. Conventional flywheels suffer energy losses of 3-5% per hour, whereas HTS based flywheels operate at <0.1% loss per hour. Large and small demonstration units are in operation and development.
