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Power Science

Scientists Who Turned Humid Air Into Potential Renewable Power Source Say 'It Was an Accident' (theguardian.com) 156

Remember those researchers who generated electricity from the energy in air humidity?

"To be frank, it was an accident," the study's lead author, Prof Jun Yao, tells the Guardian: "We were actually interested in making a simple sensor for humidity in the air. But for whatever reason, the student who was working on that forgot to plug in the power." The UMass Amherst team were surprised to find that the device, which comprised an array of microscopic tubes, or nanowires, was producing an electrical signal regardless. Each nanowire was less than one-thousandth the diameter of a human hair, wide enough that an airborne water molecule could enter, but so narrow it would bump around inside the tube. Each bump, the team realised, lent the material a small charge, and as the frequency of bumps increased, one end of the tube became differently charged from the other. "So it's really like a battery," says Yao. "You have a positive pull and a negative pull, and when you connect them the charge is going to flow..."

"The beauty is that the air is everywhere," says Yao. "Even though a thin sheet of the device gives out a very tiny amount of electricity or power, in principle, we can stack multiple layers in vertical space to increase the power." That's exactly what another team, Prof Svitlana Lyubchyk and her twin sons, Profs Andriy and Sergiy Lyubchyk, are trying to do. Svitlana Lyubchyk and Andriy are part of the Lisbon-based Catcher project, whose aim is "changing atmospheric humidity into renewable power", and along with Sergiy they have founded CascataChuva, a startup intended to commercialise the research... Catcher and related projects [received] nearly €5.5m (£4.7m) in funding from the European Innovation Council. The result is a thin grey disc measuring 4cm (1.5in) across. According to the Lyubchyks, one of these devices can generate a relatively modest 1.5 volts and 10 milliamps. However, 20,000 of them stacked into a washing machine-sized cube, they say, could generate 10 kilowatt hours of energy a day — roughly the consumption of an average UK household. Even more impressive: they plan to have a prototype ready for demonstration in 2024...

The Lyubchyks estimate that the levelised cost of energy — the average net present cost of electricity generation for a generator over its lifetime — from these devices will indeed be high at first, but by moving into mass production, they hope to lower it significantly, ultimately making this hygroelectric power competitive with solar and wind... The team accept that it may take years to optimise a prototype and scale up production, but if they're successful, the benefits are clear. Unlike solar or wind, hygroelectric generators could work day and night, indoors and out, and in many places.

Yao explains to the Guardian that "Lots of energy is stored in water molecules in the air. That's where we get the lightning effect during a thunderstorm.

"The existence of this type of energy isn't in doubt. It's about how we collect it."

Thanks to Slashdot reader j3x0n for sharing the article.
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Scientists Who Turned Humid Air Into Potential Renewable Power Source Say 'It Was an Accident'

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  • by Arethan ( 223197 ) on Saturday July 08, 2023 @05:37PM (#63669331) Journal

    Accidents, that is.

  • by JoshuaZ ( 1134087 ) on Saturday July 08, 2023 @06:05PM (#63669395) Homepage
    The energy able to taken out of the system this way is tiny. This is not going to be have many practical applications at all. We focus on groundbreaking, strange sounding, amazing things, while all the regular scientists and engineers continue the steady progress of making better solar panels, better batteries, better inverters, and all the other things we actually need. Everything is getting better for energy technologies, but not because of any new weird techs but because of doing a lot better with the basic ones.
    • by Ichijo ( 607641 ) on Saturday July 08, 2023 @06:42PM (#63669479) Journal

      The energy able to taken out of the system this way is tiny.

      Yes, 3W/m^2 is tiny compared to a photovoltaic cell at 200W/m^2.

      But normally it costs energy to dehumidify the air. This could be a real game changer in humid states for that benefit alone.

      • by RightwingNutjob ( 1302813 ) on Saturday July 08, 2023 @06:49PM (#63669489)

        $10 says it loses conversion efficiency with fouling by dust and mold growth.

        • by AmiMoJo ( 196126 )

          That might be fixable with UV light. Effective UV LEDs are now available that consume little power. You might still need to plug it in, but energy consumption would probably be much lower.

          We really need to be pushing UV cleaning technology now that it has matured. As well as the harmful stuff that needs to be kept away from humans, we now have reasonably affordable an very safe 222nm UV lamps. 222nm is safe for human contact, but kills viruses.

          Businesses could dramatically reduce staff sickness levels with

      • That's a really neat point that I had not considered.
      • You canâ(TM)t dehumidify the air for free, itâ(TM)s not a free energy device, itâ(TM)s something akin to a thermocouple, it needs a difference in air humidity and will generate a potential based on that. This is nothing new.

        Once saturated or sufficiently oxidized, it will stop, for dehumidification you then need to quickly condense and move that water somewhere else which is where the cost lies.

        • It's as if you can't generate free energy out of thin air? How unexpected...

          • by Kaenneth ( 82978 )

            It's simple, you just have to reverse entropy.

          • by dryeo ( 100693 )

            It's why windmills have never worked.

            • Actually windmills don't generate energy out of thin air. They convert wind power into rotational energy.

              Anyway, my comment was mostly ironic because as for using this to "dehumidify the air for free", "Once saturated or sufficiently oxidized, it will stop, for dehumidification you then need to quickly condense and move that water somewhere else which is where the cost lies.".

        • by Ichijo ( 607641 )

          Once saturated or sufficiently oxidized, it will stop, for dehumidification you then need to quickly condense and move that water somewhere else which is where the cost lies.

          The article says the electric current is "continuous" and if that is true then they've already solved the problem of condensing the water and draining it.

      • The energy able to taken out of the system this way is tiny.

        Yes, 3W/m^2 is tiny compared to a photovoltaic cell at 200W/m^2.

        But normally it costs energy to dehumidify the air. This could be a real game changer in humid states for that benefit alone.

        Solar requires a direct line of sight to the sun, so power per surface is relevant. However, this new method should not be restricted to 2-D, so the restriction is by volume and not surface area.

      • But normally it costs energy to dehumidify the air.

        It's not clear that this does dehumidify air. It seems to essentially be a miniature, gas-based version of Lord Kelvin's thuderstorm [wikipedia.org] in which case it extracts energy from the movement of water molecules, not their condensation.

      • Re: (Score:2, Interesting)

        by Anonymous Coward

        I'm going to go out on a limb and say that the people talking about using this as an alternative to hydro and solar are full of shit, because entropy wins every time.

        Being able to extract electrical energy out of the air from the particle motion of water just makes it sound like such a device will saturate with water, or it'll need a "dry reservoir." And that's the catch. Once it's spent, it'll need to be recharged by baking off or ejecting the water somehow. Hence Yao referring to it as a battery.
        If any re

        • Even if it is a battery, I'd be very interested in a renewable battery with long life, that can last 16-20 hours and can be "charged" or renewed during the day or whenever we have surplus power.

          But given other responses, it's probably not a battery.

      • I'm guilty, I read the article and the Wikipedia page. It's hygroelectricity, it's not about dehumidifying the air. It's about accumulating the static electricity of water droplets like a natural lightning not about water state change. Nobody read the article, everybody think these scientists are ultra dumb and don't even know energy conservation rules.
      • by jwhyche ( 6192 )

        Yes, 3W/m^2 is tiny compared to a photovoltaic cell at 200W/m^2.

        Well its still in the "look at this shit" phase of development. The time when a technology potential is not really known. With that being said, I do wonder how much power can be extracted from a given volume of air. I suspect that you would be able to generate more power near a ocean shore than in a desert.

        Until we explore the potential we won't know. Maybe eventually it can join wind, solar, and nuclear as a green answer to our power needs where practical.

    • by narcc ( 412956 ) on Saturday July 08, 2023 @07:19PM (#63669533) Journal

      I'm not one to put any stock in imagined future technological development, but this sounds incredibly foolish. Besides, it's not like a few people working on this is going to take anything away from existing tech. There is absolutely no reason not to pursue this.

      The energy able to taken out of the system this way is tiny.

      You could have said the same thing about photovoltaics for years after was discovered. It seems more than a little too early to dismiss outright.

      This is not going to be have many practical applications at all.

      Even if this never produces more than a very small amount of power, it's not hard to imagine places where, for example, a small battery would be incredibly useful, but difficult to replace. Who knows, maybe this will even turn out to easily scale up. Again, it's way too early to make these kinds of pronouncements.

      • The problem is not akin to photovoltaics where the theoretical maximum energy is high. In this case, the paper itself gives upper bounds on the energy extraction which are just not impressive. The more interesting point really was the one by Ichijo above in their comment that this tech could be used possibly to dehumidify locations without having to expend energy (which it normally takes). That seems like a more compelling argument to care about this than any thought about an energy source on a large scale
        • by narcc ( 412956 )

          In this case, the paper itself gives upper bounds on the energy extraction which are just not impressive.

          You have surprisingly high expectations. From the article:

          The result is a thin grey disc measuring 4cm (1.5in) across. According to the Lyubchyks, one of these devices can generate a relatively modest 1.5 volts and 10 milliamps. However, 20,000 of them stacked into a washing machine-sized cube, they say, could generate 10 kilowatt hours of energy a day – roughly the consumption of an average UK household. Even more impressive: they plan to have a prototype ready for demonstration in 2024.

          Even if they can only manage 10% of that in the same volume, that seems pretty damn impressive to me.

          The more interesting point really was the one by Ichijo above in their comment that this tech could be used possibly to dehumidify locations without having to expend energy

          This doesn't seem to be how the technology works. From what I can tell, it's not taking moisture out of the air, but stealing charge from moisture that passes through it. If this could passively harvest water from the air, the fact that it could also generate electricity would be an uninteresting footnote! The agricultural applications alone would

          • That shows I should really double-check something I've read earlier when I start talking about it. I agree that is much higher than I remembered and does make it more plausible as an actual energy source.
      • by Dan East ( 318230 ) on Saturday July 08, 2023 @08:50PM (#63669667) Journal

        You could have said the same thing about photovoltaics for years after was discovered. It seems more than a little too early to dismiss outright.

        No you couldn't have. Light *is* energy, and the amount of energy in, say, sunlight, is very well known. It was known up-front that a tremendous amount of electrical energy could be harnessed via sunlight, even if initial photovoltaics were extremely inefficient and only harnessed a tiny percentage of that available energy.

        In this case the energy potential is very small, as there is simply a very tiny amount of electrical / thermal potential that could be harnessed from ambient moisture in the air. We're talking at least two orders of magnitude less energy than sunlight per m^2 of surface area. Think about that for one brief moment. It would require over 200 times more surface area of this to generate the same amount of power as a solar panel. So if you had 26x26 feet of solar panels on your roof, it would take 1 square mile of surface of this material to generate the same energy.

        And again, this isn't because this material is not at its maximum efficiency because it's a new discovery - that amount of energy simply doesn't exist in ambient moisture in the air in the first place. It cannot be, unless the air was superheated or something.

        It's hard to think of a use case where solar, even with very brief exposure to sunlight, cannot outperform this new technology when we're talking 200 times the energy production over a given surface area.

        That's not to say there won't be some novel use case for this. Maybe some low-power beacon relay or scientific instrument in the arctic where there's no sunlight for days during winter. However I bet the arctic air doesn't have enough humidity (and the temperatures would instantly result in freezing when contacting the membrane) for this to function. Perhaps it would be useful in some kind of dark underground setting to power some small sensor, etc.

        • by sfcat ( 872532 )
          That's not how photovoltaics work. The energy of the photon is absorbed and causes a metal to "emit" an electron (ie generate electrical potential). The energy in the light is irrelevant as the type of metal is what determines the energy of the emitted electron. It is the number of photons above a certain energy that controls the number of emitted electrons. That's why those calculations about 40TW of power from the sun are so misleading. If we could get the energy directly from the photon somehow that
        • by narcc ( 412956 )

          Ignoring the physical and historical nonsense for the moment, there is a serious flaw in your reasoning:

          So if you had 26x26 feet of solar panels on your roof, it would take 1 square mile of surface of this material to generate the same energy.

          I haven't checked your math because it doesn't matter. Unlike solar panels, these can be stacked. You can save a lot of space when you can fold things. For example, you have ~60,000 miles of blood vessels in your body.

          It's hard to think of a use case where solar, even with very brief exposure to sunlight, cannot outperform this new technology when we're talking 200 times the energy production over a given surface area.

          Researchers at the Catcher project claim that a washing machine-sized cube (made of of the 4cm disc-shaped units they have now) could generate 10 kilowatt hours of energy a day. They plan

        • It's hard to think of a use case where solar, even with very brief exposure to sunlight, cannot outperform this new technology

          Preliminary research indicates that this will outperform solar at night time. And in other dark sitiuations.

    • by gtall ( 79522 )

      Ya, back when solar panels were first envisioned, you'd be telling them to stop screwing around and work on better oil extraction processes. And way back when those jerks invents windmills loooong ago, you'd have be there tell them to stop screwing around and work on creating bigger horses.

  • More than enough to run a clock with an analog dial, a smoke alarm, or a listening device.

    Unless of course the magic nanotubes foul quickly with dust or other environmental contaminants. Then it's just a science fair curiosity.

  • What is changing? (Score:5, Insightful)

    by darco ( 514434 ) on Saturday July 08, 2023 @06:59PM (#63669499) Homepage Journal

    For it to extract energy from a system, it must be changing *something*. So it runs on humid air, right? What is it doing to the air? How is the air different after being used by this device to generate electricity?

    Is it just taking advantage of small fluctuations in energy density over a small area? If so, how could that possibly scale to the level they are talking about?

    There must be some sort of energy gradient that this thing is taking advantage of, but of course the article doesn't describe it.

    Anyone have any ideas?

    • by aegl ( 1041528 )

      Yup. Conservation of energy says that if you build the scaled up 10kW version of this, the air coming out of it is going to be very, very cold.

      Maybe this is an air-conditioner substitute for the summer months?

      • Yup. Conservation of energy says that if you build the scaled up 10kW version of this, the air coming out of it is going to be very, very cold.

        Probably more than cold enough to freeze water - and if so, there could be a big problem with scaling this up. As the volume increases, distributing sufficient heat energy throughout the volume of the 'battery' to prevent heating could be tough. But the air conditioning angle you mentioned could be a huge win if the heat flow can be managed effectively.

      • Re:What is changing? (Score:4, Informative)

        by Racemaniac ( 1099281 ) on Sunday July 09, 2023 @01:02AM (#63669971)

        Ahh, you already fell for the marketing bullshit. They're not talking about a 10kW version, but a 10kWh/day version, so that's 400W

        But indeed, the question is what changes, and will it be possible to supply new air rapidly enough.

        • I live in a row of houses. We have a max power per house of 240x32A = 7680W sustained, that I use for induction cooking. If we have 20 of those batteries in total in all houses in our row, we could very likely do almost everything without ever having a brown out, except cooking. For the peak load of cooking it will still be problematic to do that on batteries. But if we all have electric vehicles that are integrated in the grid, even that shouldn't be an issue.

    • Since he talks about bumping around in a tube, that's kinetic energy, or in aggregate, the temperature of the humid air. There might be energy transfer, but the molecule must lose energy to transfer any energy to the tube walls. It's like some strange mechanical peltier junction.
  • I'm imagining future air conditioners that are powered by the very humidity they are meant to get rid of.
  • Is there any consequence to the extraction of this energy? The air would be qualitatively and quantitatively different than it was before it underwent this process. Would it kick off a tornado? Just spitballin'.
  • 1) TANSTAFL. As such, what repercussions does this tech have?
    2) ok, how long do these microfibers last esp with pollution in the air? Seems like pollution would block these limiting lifetime.
    3) can this work in a river or even lake or ocean? If so, waves and tides just became best friends.
  • their 'product' and expect to rent seek by surcharging you.

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