Energy

Liquid energy storage system gets the "MOST" out of the Sun

Liquid energy storage system g...
The MOST system stores solar energy in chemical bonds, which allows it to be transported and released as heat on demand
The MOST system stores solar energy in chemical bonds, which allows it to be transported and released as heat on demand
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The MOST system stores solar energy in chemical bonds, which allows it to be transported and released as heat on demand
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The MOST system stores solar energy in chemical bonds, which allows it to be transported and released as heat on demand

Solar power is potentially the greatest single energy source outside of controlled nuclear fusion, but the Sun is literally a fair weather source that relies on daytime and clear skies. To make solar energy a reliable, 24-hour source of energy, a team of scientists at Sweden's Chalmers University of Technology in Gothenburg is developing a liquid energy storage medium that can not only release energy from the Sun on demand, but is also transportable.

The Chalmers team has been working on variants of its system, called a MOlecular Solar Thermal (MOST), for over six years, with a conceptual demonstration in 2013. It differs from other attempts to store solar energy in things like heated salts and reversing exothermic reactions in that the MOST system stores the energy directly in the bonds of an organic chemical.

In this case, the scientists exposed a hydrocarbon called norbornadiene to light. This alters the chemical bonds, turning it into quadricyclane. Altering the temperature of the quadricyclane or exposing it to a catalyst reverses the effect and energy in the form of heat is released and carried off by a water jacket.

According to the team, the present system converts 1.1 percent of sunlight directly into chemical bonds, which is 100 times more efficient than the 2013 version that could only manage 0.01 percent. In addition, the new liquid storage system replaces ruthenium, a rare metal, with carbon-based elements that are much cheaper. Additionally, it can go through over 140 store and release energy cycles without noticeable degradation.

"The technique means that we can store the solar energy in chemical bonds and release the energy as heat whenever we need it." says team leader Kasper Moth-Poulsen. "Combining the chemical energy storage with water heating solar panels enables a conversion of more than 80 percent of the incoming sunlight."

The teams says the system allows solar energy to be stored and transported before being released as heat when and where it's needed.

The research was published in Energy & Environmental Science.

Source: Chalmers

10 comments
Daishi
Solar is kind of like EV right now in that it's greatly improving but still just a small portion of total market share. Solar storage is a fraction of a fraction and there isn't currently much funding in it. Arbitrage (buying energy cheap and selling it for more during demand) doesn't really exist today for the wholesale market so there isn't a lot of funding going into it. People talk about inconsistent power delivery of renewables but we need to embrace it at first and let it disrupt the status quo in the wholesale energy market so that we do create market pressure to reward inexpensive grid storage solutions. Once the market demand exists for people to store cheap solar power in the day and sell it back to the grid in the afternoon at a profit we are going to see a lot of interesting ideas/efforts in that space and I'm expecting some cool things.
Daishi
To elaborate on that a bit if you look at the trial in germany to plug EV's into the grid and allow the power company to control them I think that can/will be expanded to other storage. Lets say I have a battery bank that I give the power company access to. I should be able to give it a total capacity and a cost/watt to discharge to 50% or 85% capacity and a different cost/watt to deplete it entirely (in case of an emergency need) because of the harm fully cycling the battery would do and the additional cost that incurs. This gives the grid the ability to have very granular control of storage solutions, the ability to seek out lowest bidders, and the ability to deal with emergency demands and could be handled with a mostly simple technical backend. Another thing I expect to see is if I have a solar array I can always pump water up hill in the day, wind coils, compress air, pulley weights into the air on cables, push rocks up a hill, or use a number of non-toxic non chemical methods to store energy. Once solar creates demand for this energy shifting (from day to peak in evening) market I expect to see a lot of back yard experiments and competition for the best ways to do it. We should be able to create a fairly simple set of protocols to enable intelligent control of all of these micro storage sites in a way that isn't proprietary and allows a lot of useful research data to be extracted .
watersworm
140 "store and release" What does this precisely mean ? 140 days in winter in Northern "cold" Hemisphere, that is not the entire season (expecting all days are, shortly, sunny) ?
WilliamCocoa
Forgive me if this is a silly question - I'm curious, but not very learned on the ins-and-outs of technology. I bow to the superior knowledge of others on this forum. With that caveat, my question is as follows: I recently watched a TV program in which an entrepreneur outlined a plan to build an array of panels on the moon which would collect energy and 'beam' it to Earth in the form of microwaves. As I say, I am not knowledgeable regarding the science, so it could be a pipe dream, could be a scam - but it did make me wonder - if such a plan is feasible, is it possible to put a satellite in orbit which would do much the same thing without the expense of a moon shot and subsequent massive construction job? I know one of you will shoot this down in two sentences, but spare me not the rod - I'm here to learn. Thank you ;)
StWils
Excellent points Daishi. However "140 cycles without degradation,,"?? Get back to us when the university team can get to 10 thousand cycles or more with parts made from old tires or agricultural waste materials like feathers or fruit peels, maybe recycled beer & wine bottles, etc.
Grumpyrelic
Roughly 50% of sunlight at ground level is infrared. Some of the rest can be trapped and converted to heat. So maybe 30% more. That gives you 80% available to heat a liquid system. That heat can be stored in an insulated (cryogenic?) tank for later use. Experimental solar cells might make 40% conversion. So this new system gathers 1.1% and that is great? Am I missing something? Fabulous energy density? A safer working fluid perhaps? Don't chemical hand warmers do the same thing? When somebody converts 90% of the sun's energy and saves it for a rainy day, then I will provide a standing ovation. Spend the money instead on fusion power. Lots of extraterrestrial water out there and it would be our only ticket off this doomed rock unless some maniac pushes the button and blows us off.
the webman
WiliamCocoa, a NASA scientist proposed what's you're suggesting back in the 1970's, so you're not far off. Such a system needs to be placed in geosynchronous orbit, so it can consistently beam its power to an earth-based receiver. If I recall correctly, the scientist (unfortunately, I don't recall his name) proposed using microwave transmission for the sending system. Such a system would likely be more reliable, and suffer less transmission loss than a moon-based system, so your intuition is correct.
Douglas Bennett Rogers
It seems like a tank of Rochelle salt would do a lot better than 1.1 % and be cheaper. All of these alternative energy systems require expensive, large construction. If you aren't going to move for awhile, grid connected rooftop PV's make some sense. I was going to buy Dow Powerhouse shingles but they were discontinued. I don't have access to the bottom of the sheathing so I might not have been able to use these.
Catweazle
WilliamCocoa, the only problem with that idea is that it would be the best possible space based death ray it is possible to invent, and even if the beam accidentally became misaligned, it could be have very unfortunate consequences indeed.
Expanded Viewpoint
Hi William, In adding up all of the costs involved in building a moon based power plant (a comprehensive energy audit), it would indeed be seen to be a boondoggle of astronomical proportions (pun intended) before it was even half done. The costs would far outweigh the benefits by several orders of magnitude at the very least. And don't forget that the link from the Moon down to Earth would be impossible because the Moon orbits us. How would a stable link be maintained with a receiver? And the microwave radiation would be absorbed by and reflected off of anything in its path, like say water vapors, dust particles, airplanes and any birds that might fly through the beam. And what's the amount of energy loss in converting the solar energy into microwaves? What is the MTBF rate of the magnetron? Will there be spares that can be switched into and out of the loop as needed? I'll bet that not even one of those things mentioned was sufficiently answered by the proposer of the system, if they were brought up at all. You are wise to not take such an idea seriously. Randy