By Phil Mckenna
Superconducting magnetic energy storage (SMES) has long been pursued as a large-scale technology because it offers instantaneous energy discharge and a theoretically infinite number of recharge cycles. Until recently, however, the material costs for SMES devices have been prohibitively high for all but very small applications. Now a project funded by the U.S. Department of Energy (DOE) could pave the way for SMES technology that offers megawatt hours of energy storage. Such capacity is becoming increasingly necessary for electricity grids that need to balance the intermittency of renewable energy sources.
At a DOE Advanced Research Projects Agency for Energy (ARPA-E) conference in Washington, D.C. on March 2, Swiss-based engineering firm ABB outlined plans for a 3.3 kilowatt-hour proof-of-concept SMES prototype. The device will store electricity in the form of a magnetic field generated by direct current circulated through superconducting wires. The geometry of the superconducting coils creates a highly contained electromagnetic field, but relatively little energy is needed to sustain the field. The energy is released by discharging the coils.
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