More than 30 years in the making, high temperature superconductors (HTS) have come of age. HTS has been implemented in commercial nuclear magnetic resonance (NMR) spectroscopy systems and is now enabling several new clean energy projects, especially on compact fusion.
Compact Fusion
Superconductors can enable faster adoption of fusion – a clean energy source that is available on demand, making it an ideal candidate to mitigate environmental and climate concerns. Producing only helium as a product, fusion is without the significant safety and proliferation concerns of nuclear fission. While many clean energy sources are displacing fossil energy sources, their intermittent nature – which requires large-scale, inexpensive, and efficient energy storage – continues to limit their widespread use. In contrast, fusion does not require energy storage; it is extremely efficient, requiring merely one ton of fuel for a 1 GW power plant.
Recently, rapid innovation in high-field (>20 T) superconducting magnets is enabling compact fusion designs for a Q (net energy gain) of 10 as well as a 10x reduction in fusion device size (and thus the cost, time, and complexity). The leading fusion energy systems are based on tokomaks built using REBCO superconductor.
Power Transmission
Superconducting power transmission cables can transport 5 – 10 times more power than comparably-sized copper cables. Superconducting cables can operate at much higher current, so at lower voltages, mitigating the need for extensive right-of-way and the associated costs and delays. Low-loss, long distance power transmission from solar, wind and other renewable energy sources, generally located in remote areas, is enabled by superconducting cables.
Electric Aviation
Aviation contributes to 12% of CO2 emissions in the transportation sector. By electric aviation alone, a significant dent can be made in the ~165 million metric tons of annual CO2 equivalent emissions in today’s aviation in the U.S. [1], and the over 800 million metric tons globally [2]. Generators, motors and cables made of superconductors can be highly beneficial for low-voltage, high-current power transmission for weight-sensitive applications like electric aircraft. A fully-superconducting motor could deliver at least 4 times more specific power than that possible by a conventional motor.
Wind Generators
Wind power can be implemented faster with an order-of-magnitude increase in the ‘specific power’ (power to weight ratio) of electrical machines along with a significant reduction in losses. This can lead to more cost-effective on-land and offshore wind turbines by enabling large direct-drive generators with significantly lower tower-top mass and higher efficiency than current systems. The active weight of a
20 MW superconducting generator is about 45 tons compared to an estimated 300 tons of commercially available 12 – 14 MW generators. This leads to a significant weight reduction even as power is increased by over 30%.
Industrial Motors
Electric motors consume more than 50% of electrical energy in the U.S. and thereby greatly contribute to CO2 emissions. As in the case of electric aviation and wind generators, highly-efficient industrial motors can be realized with superconductors. While the cost of a cryocooler adds to the initial cost of capital equipment, the cost savings with increased efficiency of a superconducting machine can help realize a return on investment (ROI) within two years.
Energy Storage
Recent advances in HTS tapes and superconducting magnets that operate above 20 T and being used for fusion energy reactors can also enable superconducting magnetic energy storage (SMES) for grid-scale energy storage. SMES provides the benefits of no chemical reactions, no moving parts, essential infinite charge-discharge cycles, lower life-cycle costs, and rapid response times. The rapid response of SMES (in milliseconds) is also beneficial to in inject power to compensate for voltage sags in the grid, even multiple times consecutively.
1. EPA (2024) Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2022. U.S. Environmental Protection Agency, EPA 430-R-24-004. https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-andsinks-1990-2022.
2. J. Overton, Fact Sheet (2022) The Growth in Greenhouse Gas Emissions from Commercial Aviation“ https://www.eesi.org/papers/view/fact-sheet-the-growth-in-greenhouse-gas-emissions-from-commercial-aviation