What Would Room Temperature Superconductors do for Climate?

But, also, don’t hold your breath waiting for them

UPCOMING EVENTS

On Sept 6, meet us in downtown SF for a panel on Navigating an Equitable EV Transition, a panel produced in conjunction with the Berkeley Center for Law, Energy and the Environment.

Climate Tech COO of the Year Award

December 13 we will hold our first annual Climate Tech COO of the Year Award at Barebottle Brewing in San Francisco. We will be soliciting nominations for COO of the year soon. Chief Operating Officer is one of the least appreciated jobs in the industry, and CTAN wants to give a shout out to those hardworking COOs in the Bay Area who toil and sweat to keep the lights on and the ship running smoothly. Keep an eye out for tickets!

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If you have not yet done so, I would like to encourage you to please follow this link and take the time to write to your representatives about Hoang Thi Minh Hong and four other climate activists imprisoned by the Vietnamese government. I have written about Hong before, and she is still in jail. I cannot imagine how terrifying it must be to be a political prisoner in Vietnam, and it is the responsibility of people with privilege to speak out against injustice. I am in touch with the organizers at 350.org and trying to do what I can to help.

This Week in Climate Tech

Let’s see how many of you have been paying attention to the science news:

The correct answer is E: None of the Above! A couple of weeks ago, a South Korean lab claimed to have synthesized what might be called the Holy Grail of Condensed Matter Physics: a room temperature superconductor.

@lee_kim_1999First video of LK-99 Full Levitation, aka flux-pinning This video was just posted to the Chinese video-sharing site BiliBili and claims to be a highly pure synthesized sample of LK-99. What is the physical phenomenon behind this and what does it mean? Levitation of superconducting materials is a phenomenon unique to what is called Type-II superconductors, and is an effect whereby magnetic field lines becomes 'trapped' as it passes through the material, providing the force needed to levitate. These are the popular images and videos of cryogenically-cooled discs floating above a magnet frequently seen online and in the pinned post on my profile. You can think of this like strands of hair being caught in gum - the gum is suspended in mid-air by adhering strongly to the hair as the hair passes through it. The hair in this case is magnetic field lines and the gum is the Type-II superconductor. Just like hair comes in individual strands, or in other words hair is 'quantized' or 'discrete', so is the flux trapped at the 'pinning centers' quantized in what are called 'magnetic vortices' - the quantization of pinned flux lines is a key property and distinguishing characteristic of Type-II superconductors (although technically can occur in Type-I superconductors if the material thickness is smaller than the London penetration depth, which is indeed very small - specifics for the physics nerds out there). Flux-pinning is entirely unique to superconductors and is also wholly distinct from the Meissner effect. It is not a property of diamagnets or diamagnetism. TRIUMFLab contributed to flux-pinning studies in Niobium crystal superconducting radio-frequency cavities used for particle acceleration. In that application, trapped flux poses an issue by increasing the remnant surface resistivity of the cavity, which has the effect of decreasing its effective quality factor or Q-factor, which is a measurement of a resonators efficiency. SRF cavities typically have Q-factors of 10E10 and trapped flux at pinning centers reduces the maximum effective accelerating electric field used to drive charged particle bunches close to the speed of light. Flux pinning is thought to arise in some Type-II superconductors by small imperfections in the crystal, also called volume defects, that enable flux to penetrate the material. In SRF cavities an issue that arises is any magnetic field that is passing through the material, e.g. by the Earth's background field, can become pinned or trapped inside the cavity as it transitions into a superconducting state. See some attached plots in the comments from a study showing how the surface resistivity of SRF cavities increases the more there is a background field as the cavity transitions into superconducting state. This is the first video I am aware of that claims to show the flux-pinned levitation of a LK-99 sample. If this is in fact what is happening, then it is a very unique and promising finding of this new materials properties and potential for future study. If this is real then it is truly ground-breaking Prof. Hyun Tak Kim: "LK-99) showed 5.450 times stronger level of zero electrical resistance than sample materials better than graphite. It also exhibited 23 times better zero resistance compared to low-quality samples," said Kim during the interview. "These results cannot be explained other than superconductivity." The researchers at the Korea University of Energy and Industry confirmed that the sample crystal structure of the new material 'LK-99' developed in Korea is the same as the crystal structure presented in the paper. The Energy Institute of Science is the only external institution being studied by receiving a sample of LK-99 made by the Quantum Energy Institute. #quantumphysics #quantumlocking #gravity #quantum #lk99

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Since then, the internet has been abuzz with videos of tiny floating rocks, supposedly demonstrating a property of superconducts, known as “the Meissner effect”.¹ Nerds all over the world were very excited. But, alas, it all turned out to be a case of premature publication: no one has been able to reproduce the results, and a pre-print of a paper this week (one of probably many to come) attributed the floating to “soft ferromagnetism” instead of superconductivity².

But what if it had been real? What would the implications of a room temperature superconductor (RTS) be for climate change? Well, let’s back up for a second. What’s a superconductor?

All materials have an electrical resistance. If you try to use them for a wire to conduct electricity, some will work better (those with low resistance, like copper), and some will work very badly, like plastic and rubber. We call these conductors and insulators, respectively, and that’s why we put the plastic on the outside of the copper wire, and not vice-versa. The resistance of materials is usually correlated with their temperature, and most metals have a resistance that goes down with lower temperature. And some metals, like mercury, and lead, exhibit zero electrical resistance at very low temperatures. These are called superconductors: materials that can transmit electricity perfectly, with no loss of energy³.

In 1987, a new class of superconductors were discovered that were called high temperature superconductors: these could operate at the balmy temperatures above -320°F, which means that they can be cooled to superconductivity using only liquid nitrogen, as opposed to liquid helium, which is much colder and much more expensive to make⁴. There have been some improvements in superconductors since then, but surprisingly few, and there are still no superconductors that work at anything approaching room temperature and ambient pressure. As a result, superconductors have remained largely confined to applications such as high power MRIs that require very the kinds of very high magnetic fields that can only be generated with superconducting coils.

But let us imagine that we actually did have room-temperature superconductors. What could we do with them that would help the climate?

The most obvious things would be creating very highly efficient electrical devices. Electric motors, long-distance transmission lines, and electric generators all lose lots of energy to electrical resistance. Improving the efficiency of these devices would reduce energy usage across the board, and improved energy efficiency is one of the best short-term things we can do to reduce the emissions from electricity generation.

There are other possibilities for improving transportation efficiency as well: floating “maglev” (magnetic levitation) trains are the fastest in the world, and room-temperature superconductors would make maglev trains significantly cheaper to build, creating more carbon neutral transportation options. In addition, decarbonizing flight would be made much less difficult by more efficient electric motors.

Energy storage is also a significant challenge for decarbonization, because renewable energy relies large on wind and solar, which mostly work during the daytime. So, creating a stable electrical grid requires very large amounts of energy storage, to allow energy generated during the daytime to be used at night. Superconducting Magnetic Energy Storage (SMES) is a very simple method of creating high density energy storage: electricity can be injected into a ring of superconductor, and will continue to circulate indefinitely without any losses due to resistance.

There has also been a lot of progress on nuclear fusion over the past few months (more on this next week!), and practical fusion power generation would certainly be a major boon to carbon neutral energy. Nuclear fusion reactions are so hot that they would destroy any physical containment; tungsten, the most temperature resistant metal, metals at about 3500°C, whereas nuclear fusion occurs at around 100 million degrees. The only two ways to contain a fusion reaction are with magnets, and lasers⁵. Superconducting magnets are capable of providing the huge magnetic fields required to confine a fusion plasma, which could potentially lead to practical fusion generation.

There are so many applications of superconductors that it’s hard to know exactly what the impacts would be. But the LK-99 saga teaches us something else as well: it’s easy to wait breathlessly for the next major scientific breakthrough, and hope that it will solve climate change. But in truth, there are no silver bullets, and there are a lot of con men out there. If we are going to solve climate change, we will probably have to do it the old-fashioned way: by hard work.

1. The little rock floats because superconductors expel magnetic fields, so instead of being able to fall onto the magnet, it can’t penetrate the magnet’s field, and it floats above it instead. Exercise for the reader: Use Lenz’s Law to explain the Meissner Effect.

2. This kind of thing happens in science all the time. I am old enough to remember when “cold fusion” was a punchline on late night TV.

3. The story goes that when Kamerlingh Onnes’ research assistant discovered superconductivity in lead at near-absolute-zero temperature, Onnes told him he was a dummkopf and to go back and and redo the experiment. Onnes won the Nobel prize in 1913.

4. Back when the earth’s crust was still cooling, and great beasts roamed the land, I bought a little chunk of high temperature superconductor and a rare earth magnet from Edmund Scientific. I got some liquid nitrogen from a dermatologist that my mom knew, and I did a science fair demonstration about electromagnetic induction with a friend of mine, Dave McDonnell. Dave was more into saxophone than science, and was lucky to have me as a science fair partner, because he didn’t actually have to do anything.

5. At least, here, on earth. Stars are a giant fusion reactors, contained by their own gravity.