Storing the Sun’s Energy in Liquid Could Change Solar Forever

Last Updated on June 20, 2021 by Matthew Donnelly

The sun puts out a lot of energy, more of it hits the earth in an hour than humankind could use in a year And we’re really not taking advantage of it, the US got less than 1% of its electricity from solar power in 2016. If we could get that number higher, we could run our homes, cars, toaster ovens, all with zero emissions. That’s the dream anyway, some perfect future with limitless free energy.

So what’s in the near future for this future? Where does solar power go from here? One of the big problems is what do we do when there’s no sun? Like on cloudy days. Or at night time. If we’re going to go all solar, we need a way to store the suns energy. Usually, we combine solar panels with rechargeable batteries, but batteries are pricey and they kinda suck. So researchers in Sweden are working on how to catch the suns energy in a bottle, or at least in a little tube. Those crazy Swedes developed a liquid with an intriguing property. The molecules in the liquid react when exposed to light and become isomers; meaning they still have the same makeup, but in a different arrangement than normal. This new arrangement stores energy, and when a catalyst is introduced, it shifts the molecules back to their usual structure and releases the stored energy as heat, which could be used to warm homes at night or generate electricity, provided enough heat is released.

Recently the researchers switched from expensive ruthenium to the more common elements carbon, hydrogen, and nitrogen to build their molecules; this makes the process cheaper and easier. On top of that, they’ve actually increased their storage capacity by a hundredfold! Ok so… they could only store 0.01% of the energy that hit it before… and a hundredfold increase means just 1.1%, but still, progress! Storage isn’t the only issue. The panels themselves are also expensive If we could make the solar panels cheaper that would go a long way to creating a competitive source of energy compared to fossil fuels and other renewables. 90% of photovoltaic cells today use crystalline silicon, making them expensive to manufacture and the process creates toxic by-products. But an entirely different approach does exist: Using perovskites. Perovskites have a crystal structure of tetrahedral arrangements of atoms and molecules, and depending on which elements are used they have different properties. They could be superconductive, magnetoresistive, or photovoltaic. Solar cells that use them are cheap and easy to assemble and could now be on par with silicon cells in terms of energy efficiency.

But you may have noticed every rooftop in sight isn’t covered in perovskites. That’s because they have a fatal flaw: the cells are unstable, and extreme light levels, temperature, and humidity cause them to decompose. Even normal weather can destroy them, which is bad because you typically see a lot of weather outside, the place where solar panels need to be. As result perovskite cells only function for several months, compared to silicon cells which can last more than 25 years. But hey, a decade ago perovskite cells only lasted a few minutes. Again, progress! Scientists are constantly coming up with new and ingenious ways to make the sun do our bidding, and these are just a couple of things currently in the works that show promise.

Though we don’t use much of it now, breakthroughs and innovation could lead to a world powered cleanly and sustainably by sunlight. The future of solar power looks bright. There are crazier ideas for solar-like putting panels in space and beaming electricity to Earth, but a massive project like that would be insanely expensive. They’re fun to ponder though, so Trace covers some far our geoengineering projects here. Do you have a favorite renewable energy technology that’s not quite ready yet? Let us know in the comments, so I can see how many of you say thorium reactors, subscribe for more, and thanks for watching Seeker.

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