Why This Liquid That Stores Solar Energy for Years Matters

Do you think molecular bonding sounds like a promising direction? To start comparing quotes and simplify insurance-buying, check out Policygenius: policygenius.com/undecidedwithmatt Thanks to Policygenius for sponsoring this video! If you liked this, check out Exploring Solar Panel Efficiency Breakthroughs in 2022 https://youtu.be/m8crjuL8FFs?list=PLnTSM-ORSgi7UWp64ZlOKUPNXePMTdU4d

It would be good to plan for '1 Year later' or 'several years later' videos on some of these technologies. It would show which of these technologies did or will break through.

You didn't specify the energy density of the MOST fluid, so I found it for you. It's 396kJ/kg, which is 110Wh/kg. Lithium ion batteries are almost 3 times that. Volumetric density is 359 kJ/L (100 Wh/L), compared to more than 730 Wh/L for Lithium ion batteries. Maximum theoretical specific density is "966 kJ kg−1 = 268 W h kg−1 (unsubstituted norbornadiene)" from the paper. I don't know if links are permitted. Anyway, they're using derivatives to increase the energy collection efficiency, and possibly stability, so you can have 3%, 18 years or 268 Wh/kg, not all at once. The idea of using this to power headphones and mobile phones is ridiculous, "both" from the energy density, the flammability, the toxicity, the heat generation, and the fact you need a TEG or a Stirling engine generator in the device. The chemistry is based on Norbornadiene-Quadricyclane photoisomerization. Norbornadiene is flammable, Quadricyclane is flammable and toxic. It might be useful as a way to extract/store energy from short wavelength sunlight (~300nm) as an addition to other technologies that doesn't perform well with those wavelengths. E.g. as a thin layer of fluid channels on top of solar cells. In that case it could probably cool the PV cells, increasing its efficiency. If it blocks too much of the useful light this would be useless of course.

The problem unfortunately with these "meta stable" isomers that are high energy, is there is a substantial decay rate generally speaking. I wouldn't be surprised if that "shipped liquid" had lost at least 3/4s of it's "high energy" isomer. High energy states aren't really that metastable if they were easy to get to, versus say a redox reaction like reducing CO2 to methane, where substantial energy is involved, any oxidation/energy release would be completely insignificant. This is just an isomerization, granted a pretty good one but easy come easy go, it's not as if we have carbons being reduced here. Redox reactions generally just release more energy too, if you put it on par with Lithium I'd say head to head good ol' Lithium batteries would probably outdo this in energy density, couldn't say by how much, but guesstimate 50%. Even if the conversion is higher energy than I think, say extreme UV wavelengths, most of that energy is filtered out by our ozone layer. This would make sense to me if it's decay rate is reallllllly small. This isn't a jug of gasoline you can use years later. Similar to a nuclear isotope (or evaporation of gasoline from a lackluster container) there will be decay, and likely very very significant. Anything to stabilize it will invariably lower efficiency further by pushing the envelope of bond breaking higher. Also.... catalysts are generally not cheap, what they are using really matters here (is it Nickel mesh on carbon? is it palladium?). I always thought photo switching was a cool concept, but after a Master's on this shit, it's still too much of a gimmick for real world high energy processes. I know it seems Im shitting all over it...I kind of am....it does have some pretty neat applications, as a SWITCH...not as an energy medium. You would likely have much higher efficiencies with concentrated solar simply heating a material engineered to have ungodly heat capacity, versus a single bond based conversion of isomers. Capturing photons is best left to large conjugated bonds or metals chelated complexes with lots of happy d orbital electrons to do the jumping states.

I had heard that the CSP tower plant you referenced had closed and was not currently active. This was mainly due to corrosion in the pipes, lowered output than predicted and an accident. It’s good to see they got it back up and running. Thank you for mentioning it, as I thought this project had been abandoned after this accident.

I find the concept of light directly converted to chemical storage then converted straight to heat in a closed loop system very interesting. The conversion efficiency of light to doesn't need to be real high if you can collect for 8 months to get you through 4 months of heating during the winter especially since you would be collecting during the long days of summer to use during the short days of winter. Appropriate sizing of the system with long term storage would be easier also as you wouldn't have to over build your system in summer to insure enough in winter. I like the idea of having a 120 degree F heat source on winter days with a high of -10 degree F when even air - air heat pumps don't operate efficiently. It would be important to know life span expectancy of this system as I am disappointed in compressor life in heat pumps.

My first thought on this is using it to cool the photovoltaic panels so they'll work more efficiently. Then use a combination of battery storage and this to provide power when the sun isn't shining.

I like it! It sounds like a trade-off between efficiency and convenience/affordability. The fluid doesn't capture a large amount of solar energy, but the energy it does capture is rendered into a stable, portable form that can be piped around and used in countless different ways. I don't think anyone will be storing it for years when the sun will still be shining tomorrow, but there's definitely a case to be made for storing sunlight in the summer and using it in the winter.

I wonder if this could also be an alternative for long distance transmission via existing or converted pipelines. Wired power transmission typically has a 5% loss. How efficient would be the conversion be if you used a laser diode tuned to the best absorption frequency?

Not sure if I missed it in the video, but do we know the storage density of this liquid? How much would be required in a closed loop to provide X amount of heat energy?

This is cool because it is a new technological concept I haven’t seen before, rather than just a refinement of an existing concept. The isomer + catalyst approach is fundamentally different from producing a liquid fuel that requires later combustion (and needs careful handling from combustion dangers), or straight thermal storage. And because it’s liquid, it could theoretically be made in sunnier areas and shipped to less sunny areas, if the energy density makes shipping worthwhile.

7:36 - Whenever I hear that something mechanical is controlled by machine learning and AI, I'm skeptical of it. That's entirely marketing speak. Why is there a need to adjust things 30 times a second? The sun moves half an arcsecond in the sky in that time. What mechanical system is going to have that accuracy? Also "While most systems usually" -> "this system is capable of" sounds like this system has not yet been optimised and so they're throwing around big numbers to make it sound impressive. The point of the current systems heating to ~500C is because that's the operating point for the working fluid (salt). They could heat up much higher than that if they weren't cooled by the working fluid.

I'd be curious to know how this compares to the original chemical method for storing solar energy: photosynthesis. Years ago I read about a project that was growing algae in tubes that had CO2 bubbling through them. The CO2 came from electricity generation (ideally, a solid oxide fuel cell) that used the algae as feedstock in a semi-closed-loop system. It doesn't seem to have gone anywhere, so maybe it didn't really work? But it sounded promising at the time.

Concept is interesting but 3% efficiency for storing thermal energy is amazingly poor. Consider that photosynthesis can be 6% efficient, takes CO2 out of the air, and cellulose can retain that stored energy for a very ling time.

Cold climate heating during winter for residential. Here in Canada a large portion of our carbon release is for heating, a system like this that could harvest and store heat in the warm months for winter use would be great but as always cost will matter.

They had some CSP plants in the Kramer Junction/Harper Lake area of California. Spent billions and they are no longer operating. Any idea why they shut them down?

Very interesting tech! Engineered storage in molecular bonds makes a lot of sense long term. It is, after all, why traditional fuels have been so successful. It strikes me that the efficiency does not have to be terribly high if it is cheap to deploy a lot of surface area. Certainly a square meter of glaze red glass with a fluid flowing through it would be far cheaper than square meter of polycrystalline silicon.

I’m quite convinced we all need to capture as much of solar heat we can get and store it in materials that can stand the heat. Only non toxic materials should be used for underground storage where leaks may occur. Earth is a good keeper of heat which can free this energy during winter. Low temperature but mass heating (like floors) during winter is best for small energy losses. You don’t need 18 years of storage. And of course insulation counts.

Love your channel! This technology looks really promising. Now I'm curious... how toxic is the solution/waste after the 18 year storage capacity has passed?

even working with the heat. This could be quite helpful here in the winter. Store up excess energy in small amounts through the summer to have a tank of stored energy that could slowly be used in the cold months to increase home temps and reduce heating costs would be amazing.