On This Day: Superconductivity discovered, now a potential technology to help combat climate change - Apr. 8, 1911
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Superconductivity
Superconductivity is a set of physical properties observed in certain materials where electrical resistance vanishes and magnetic fields are expelled from the material. Any material exhibiting these properties is a superconductor. Unlike an ordinary metallic conductor, whose resistance decreases gradually as its temperature is lowered, even down to near absolute zero, a superconductor has a characteristic critical temperature below which the resistance drops abruptly to zero. An electric current through a loop of superconducting wire can persist indefinitely with no power source.
Superconductivity was discovered on April 8, 1911, by Heike Kamerlingh Onnes, who was studying the resistance of solid mercury at cryogenic temperatures using the recently produced liquid helium as a refrigerant.[26] At the temperature of 4.2 K, he observed that the resistance abruptly disappeared. The precise date and circumstances of the discovery were only reconstructed a century later, when Onnes's notebook was found. In subsequent decades, superconductivity was observed in several other materials. In 1913, lead was found to superconduct at 7 K, and in 1941 niobium nitride was found to superconduct at 16 K.
Great efforts have been devoted to finding out how and why superconductivity works; the important step occurred in 1933, when Meissner and Ochsenfeld discovered that superconductors expelled applied magnetic fields, a phenomenon which has come to be known as the Meissner effect.
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https://en.wikipedia.org/wiki/Superconductivity
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Role of Superconducting Materials in the Endeavor to Stop Climate Change and Reach Sustainable Development
Journal of Superconductivity and Novel Magnetism
Published: 03 February 2023
Lately, superconducting devices such as flywheel energy storage, fusion energy, and superconducting magnetic energy system (SMES) were intensively developed, despite their discovery long ago. The superconducting flywheel energy storage system stores electric energy as kinetic energy of a rotor suspended contactless on superconducting bearings. Kinetic energy of the flywheel can be converted to electric energy whenever needed. Fusion energy as a new clean energy source could be realized only after development of superconductors producing strong enough magnetic fields, up to 20 T. Hot plasma is enclosed and condensed by a huge magnetic field, which prevents its contact with any solid surface and is converted into electrical energy. SMES uses superconducting coils to carry loss less electric current and store its magnetic energy. It can serve in a large number (almost infinite) charge/discharge cycles with a high conversion efficiency of more than 95%. A SMES can roughly store 5 GWh, but requires a large amount of space for superconducting current loop (~?0.5 miles) with cryogenic confinement. Energy harvested in inhabited hot deserts or hot climate countries from renewable sources like sun or wind can be transferred without attenuation using superconducting cables over long distances to people in need. Evidently, superconducting technology can pave ways to harvesting clean energy at large scales using various systems. However, one of concerns is cost of installation and maintenance. Superconductors must be cheap, advanced in properties, and mass producible. Here, we present the summary of development and progress of bulk (Gd,Y,Er)Ba2Cu3O7-x and bulk MgB2 superconductors toward making them cost-efficient by a technology addressing the climate issues and global warming.
In 2015, Railway Technical Research Institute (RTRI) completed one of the largest superconducting flywheel energy storage systems to that date, with energy storage capacity of 100 kWh, output of 300 kW, and maximum revolution speed of 6000 rpm. To generate these numbers, high temperature superconducting bearings were used and the cryogenics was managed so that the maintenance expenses made this system outstanding. For harvesting more energy, especially in the form of solar and wind energies, huge areas must be used to setup the solar panels and/or windmills. Since these types of energy are geographic dependent, the best positions might be far away from the human colonies, like hot deserts and areas in inhabited regions. In such cases to maximize the energy, we can use superconducting cables to transfer energy from remote areas to human colonies without attenuation losses. The same can be applicable to wind and hydro energies. Simultaneously, we can also employ superconductors to enhance the performance of application; for instance, a superconducting device employed in a wind mill motor can generate twice the power of a regular motor. On the other hand, magnetic energy storage provided by superconductors with a fast response and long backup times is required for a successful transition from fossil fuels to wind and solar power.
Superconducting cables have a great potential for many sectors such as power transfer, fault current limiters, Maglev, etc. The main challenge is to arrange transport of the energy harvested in deserted but rich of natural energy areas (like deserts, windy regions, and underground) to civilian societies. This looks to be a pipe dream, but with a considerable advancement in superconducting technology, it can become a reality. Due to high Tc they can be cooled to superconducting state using liquid nitrogen or by cryogen-free cryocoolers. They could be considered equivalent to optic fibers in high-speed information transfer. The president’s national energy policy mentions that superconductors are one of the promising technologies that will improve transmission, storage, and reliability of renewable energy. Recent technological advances in the high-temperature superconducting underground power transmission cables will enable an increased access to all forms of energy, including renewable energy. These cables will allow 300% rise in capacity without excavations to lay new transmission lines. Another example is the use of superconducting technology to reduce the energy consumption in the railway systems. The superconducting cable allows to reduce energy consumption in electric railcars requiring a large amount of electric current to accelerate. Simulations estimated that use of superconducting cables could save 5% energy per day on an average general city railway model. This is because of cryogenic cooling energy is less than the amount of regeneration and joule heat loss. One of the main challenges in this technology is the high expense of cryogenic technology and long-distance cryogenics pumping. It has to be solved with the advancements in that field. In any case, the superconducting cables are crucial to stop and reverse the climate change.
The role of superconductors in a sustainable technology is crucial due to the impending climate disruption caused by greenhouse emissions. Superconductors play a promising role in loss-less energy transportation as well as storage, which are important to efficiently utilize the power from renewable energy sources. HTS materials’ performance and low-cost fabrication steadily advance. The production methods [discussed in the paper] are cost efficient techniques that can lead to enhancement in performance, paving path to commercialization of the superconductors as a sustainable technology.
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https://link.springer.com/article/10.1007/s10948-023-06515-6
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