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Researchers Produce 'Green' Hydrogen With Over 90% Efficiency 56

Bruce66423 shares a report from The Jerusalem Post: A team of researchers from Tel Aviv University has produced 'green' hydrogen -- hydrogen that is produced without polluting carbon dioxide emissions but is still highly efficient, the university said. The TAU team produced hydrogen using a water-based gel to attach the enzyme to the electrode and a biocatalyst. Over 90% of the electrons introduced into the system were deposited in the hydrogen without any secondary processes.

"Hydrogen is very rare in the atmosphere, although it is produced by enzymes in microscopic organisms, which receive the energy from photosynthesis processes," explained Itzhak Grinberg, a doctoral student who helped lead the project. "In the lab, we 'electrify' those enzymes. That is, an electrode provides the energy instead of the Sun." However, the challenge is that the enzyme generally "runs away" from the electric charge when making hydrogen in a lab. The hydrogel holds the enzyme in place. "The material of the gel itself is known, but our innovation is to use it to produce hydrogen," said Prof. Iftach Yacoby of TAU's School of Plant Sciences and Food Security, who oversaw the project. "We soaked the electrode in the gel, which contained an enzyme for producing hydrogen called hydrogenase. The gel holds the enzyme for a long time, even under the electric voltage, and makes it possible to produce hydrogen with great efficiency and at environmental conditions favorable to the enzyme -- for example, in salt water, in contrast to electrolysis, which requires distilled water."

The team also tested the gel with two other enzymes and proved that the hydrogenase could attach different enzymes to the electrode. "Today, 'green' hydrogen is produced primarily through electrolysis, which requires precious and rare metals such as platinum along with water distillation, which makes the green hydrogen up to 15 times more expensive than the polluting 'grey' one," said doctoral student Oren Ben-Zvi, who co-led the experiment. Therefore, the hope is that in the future, TAU's method could be commercially implemented to lower the cost of green hydrogen production and hence enable its use in more industries and agriculture, thereby reducing CO2 emissions and making the planet healthier.
Their research was published in the journal Carbon Energy.
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Researchers Produce 'Green' Hydrogen With Over 90% Efficiency

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  • What's the energy efficiency?

    • by etash ( 1907284 )
      probably terrible, since they don't announce it and just mention the quantum efficiency.
    • by Rei ( 128717 ) on Wednesday July 19, 2023 @04:09AM (#63698396) Homepage

      The actual article says:

      Finally, by integrating the area under the current curve for the total charge (Figure 3D–G) and considering the moles of H2 that were produced (Figure 3C), the Faradaic efficiency was calculated and found to be 80%–90% for all the tested conditions.

      Faradaic efficiency = total moles produced divided by theoretical maximum from the total amount of charge passed.

      Now for the bad news:

        * Using a thermal energy source, you can already approach if not achieve those sorts of efficiencies with high-temperature steam electrolysis, using the waste heat from the generation as an input to the endothermic process.

        * Fuel cells have a hard limit of 83% efficiency, due to the laws of physics (you must output at least 17% of the energy as heat, not electricity). In practice, you get well less even in ideal conditions, and since optimal efficiencies are only at low power outputs, in real-world vehicle conditions, you get well less than that still.

        * They're only talking about the efficiency of specifically the reduction of protons to H2.

        * This process is biological (the only new achievement is binding the enzymes better to the electrode), based on [Fe-Fe] hydrogenases. They're only looking at the scenario for where you already have the enzymes, and completely ignoring the aspects of "what you have to do to make it" and "how long it lasts", among others. Many biological processes are extremely efficient when taken in isolation (ATP synthase for example is nearly 100% efficient), but net biological efficiencies tend to plunge as their losses accumulate in chains.

        * Indeed, that 10-20% loss is in the form of "unwanted side reactions". If those "unwanted side reactions" are in any way inactivating or destroying the enzymes, then you have to be making or repairing entire enzymes for 1 in 5 to 1 in 10 hydrogen molecules that you produce. Which doesn't even remotely sound efficient. They don't investigate in detail what the consequences of the "unwanted side reactions" are.

      • by jaa101 ( 627731 )

        Even worse is that hydrogen for many applications needs to be highly compressed to make it portable. This process is energy intensive and can reduce overall efficiency by another 20%.

      • by cmseagle ( 1195671 ) on Wednesday July 19, 2023 @07:46AM (#63698660)

        * Fuel cells have a hard limit of 83% efficiency

        There are uses for green Hydrogen that would cut carbon emissions without putting a fuel cell in the middle of the process. I read an estimate that you could simply mix 10% Hydrogen into household natural gas supplies without needing to retrofit appliances. There are also industrial uses like steel smelting where you could burn hydrogen instead of gas to reach to high temperatures required.

        • by dbialac ( 320955 )
          There's also an ICE, but too many people want to overlook the fact that an ICE is just an engine that requires a liquid or gaseous combustible fuel to burn.
          • by jaa101 ( 627731 )

            ICEs have an NOx problem that fuel cells avoid.

            • by dbialac ( 320955 )
              Lets avoid scope creep. We're trying to solve the carbon problem, not wait for the perfect solution to come up. Every day we kick the can down to something that is years off, we're years off where we could be. The ICE has been in production mode since the 1800s. Fuel cells have been in development mode since before the moon landings. I had a fuel cell that I used on a camping trip. It worked, but it wasn't close to being able to supply the amount of amperage that it was supposed to. It was also finicky. It
          • by Waffle Iron ( 339739 ) on Wednesday July 19, 2023 @10:38AM (#63699070)

            There's also an ICE, but too many people want to overlook the fact that an ICE is just an engine that requires a liquid or gaseous combustible fuel to burn.

            You should watch the YouTube video on the excellent "Engineering Explained" channel where he covers the ridiculous BMW V-12 hydrogen car from 2005.

            Hydrogen is already bulky enough if you use a fuel cell. Using an ICE engine that is several times less efficient just compounds the problem. Much of volume this large luxury sedan is taken up by the giant liquid hydrogen fuel tank, which all evaporates within two weeks if you don't use it, BTW.

        • > I read an estimate that you could simply mix 10% Hydrogen into household natural gas supplies without needing to retrofit appliances.

          It would reduce carbon emissions even more to burn the natural gas in a turbine to produce electricity, then use that electricity to run heat pumps and induction cooktops.

          Also the only actual, practical proposal I've read for diluting/replacing natural gas with hydrogen - which was targeting the London area IIRC - required gradually replacing all of the existing natural

        • There are uses for green Hydrogen that would cut carbon emissions without putting a fuel cell in the middle of the process. I read an estimate that you could simply mix 10% Hydrogen into household natural gas supplies without needing to retrofit appliances. There are also industrial uses like steel smelting where you could burn hydrogen instead of gas to reach to high temperatures required.

          Combustion of the hydrogen is generally the least efficient way of using the hydrogen, other than using it to produce heat. But even then there are more efficient ways to do it.

          There's also an ICE, but too many people want to overlook the fact that an ICE is just an engine that requires a liquid or gaseous combustible fuel to burn.

          Running an ICE on hydrogen is very inefficient - you're just piling on the inefficiencies.

          Fuel cells are pretty much the most efficient way to convert hydrogen to useful energy. If you're making a car, a fuel cell EV is pretty much the only way to go - an hydrogen powered ICE would require way more hydrogen than we currently can store in a car-sized vehicle just to run it a decent distance. Heck, there are demo vehicles out there, and the big problem is the tank is too large to insulate properly, so half the hydrogen will boil out just from sitting there in a day. If you're not already running from hydrogen station to hydrogen station, you're filling it up daily.

          Hydrogen ICE vehicles are basically just a form of greenwashing because combusting hydrogen first produces less power but is so inefficient you'll have range anxiety because we can't make a tank large enough to fit in the vehicle. You'll get far further with a fuel cell EV and a much smaller tank.

          Even so, a BEV is still far more efficient when you replace the tank, the cryogenics and fuel cell with a battery.

      • They're only looking at the scenario for where you already have the enzymes, and completely ignoring the aspects of "what you have to do to make it" and "how long it lasts", among others.

        Yeah, I thought the headline was bullshit. If it isn't a cradle to grave measurement, then it's worthless.

      • It's better than burning hydrocarbons ... but will always be worse than generating electricity directly

      • Thanks for trying to explain. Maybe you can tell us why anyone should care? Sounds very limited in scope of effect.

        They figured out how to force a charge to stay next to something that didn't want to. OK. Is there another situation where this is useful or important?

  • making the planet healthier

    As in more healthy and from an implied current state of already positive health? I think I'll take it as it is.

  • I'd like to read that article but the server isn't responding.
    The summary doesn't specify what the source of the hydrogen is or what the byproducts of the catalyzed reaction are.
    • by AmiMoJo ( 196126 )

      Even if the hydrogen production was 100% efficient, you still need a large industrial site to make it, and then transport it to where it is used. Can't just send it down a wire like electricity.

      • True, but the reason for producing hydrogen is that it is a more energy-dense source of potential energy than common electrical storage devices like batteries and capacitors, making hydrogen a useful energy source as fuel for vehicles.
        • But most vehicles would do just fine with batteries...

          Majority of commutes is within 30 miles - even current batteries are more than enough...

          And future models might be fine for 95% of uses...

          Investment in hydrogen might not be worth it...

          • by divide overflow ( 599608 ) on Wednesday July 19, 2023 @04:12AM (#63698398)
            And I agree with you. But long haul transportation provides use cases that favor fueled vehicles.

            I personally see too many problems with using hydrogen as a fuel, many of which are only known to people who have actually handled hydrogen and developed systems that use it as fuel. Hydrogen does NOT like to be contained, with a boiling point of -252C/-423.2F it cannot be practically stored as a liquid in a vehicle, it's hard to keep the gas from leaking out of connectors and tanks, it tends to embrittle metals, it's even hard to measure the flow rate of the gas through a tube as conventional flow rate measuring devices won't work with hydrogen.

            So yeah, I'm also skeptical about most proposed use cases of hydrogen as a fuel.
            • A large amount of companies are doing R&D on LH2 refueling, with the first demonstrators already out. Toyota has participated in an endurance race with LH2 (and BMW did a LH2 roadcar prototype decades ago).

              Almost all of it is funded based on private risk, not a government boondoggle.

              • Neither of them are amounting to anything. BMW never did anything beyond a tech demo and are all in on electric. Toytoa are now coming around after being virtually the only company in the world that was actively investing in hydrogen vehicles.

                Forget it, it's dead. The H2 refuelling is an active business for companies producing large trucks and heavy industrial machines. The car fantasy has got to die.

                • Divide Overflow was saying it's entirely impractical, not for cars, not for trucks. I was just pointing out the trucking industry is investing a lot of their own money in it and it's practical enough to endurance race with.

                  That said, IF a LH2 distribution network for trucks is created, I could see some consumer truck companies piggy back on it. Drive your truck to the grocery store most of the time on battery, use LH2+fuel cells for range extension when you tow your boat to the lake. In the consumer whore A

            • by AmiMoJo ( 196126 )

              A lot of long haul could be replaced by electric trains. Especially maglev, which is on capable of speeds similar to aircraft.

              The issue is political. First you need to fund it, and it is a big investment compared to an airline buying another plane, or even building a new airport.

              Secondly you need to secure a route for the track. These days terrain isn't such a big issue - the Japanese maglev line is 90% tunnels through mountains. But in many countries, access to the needed land is politically difficult.

              So i

            • by e3m4n ( 947977 )
              Its either H2 or petrol for air travel. Its the only 2 viable options. Carrying 600 tons of lithium batteries and/or tripling flight times for propellors on trans Atlantic flights are a non-starter. Unless ET plans on enlightening us with whatever physics being employed on those UAP sightings, H2 is our best bet on air travel.
              • Its either H2 or petrol for air travel. Its the only 2 viable options.

                Erm... jet engines don't burn petrol.

                If green hydrogen becomes the only fuel, I suspect it'll push the per-km price up considerably & possibly make some flights impractical. But that's not such a bad thing. It may become more inconvenient, expensive, & time-consuming to travel longer distances, which could reduce the overall amount of "necessary" travel, e.g. Do we really have to fly half way around the world to sit in a typical luxury hotel by a typical beach when there are plenty of luxury hote

                • by e3m4n ( 947977 )

                  Erm... jet engines don't burn petrol.

                  wow, its best to not speak so others only suspect you are dumb than open your mouth and confirm it. JP-5 is a petrol/naptha mixture very close to diesel. Similarly so is JP-4 and JP-7. In the Navy everything used JP-5, jets, helicopters, diesel generators. It was the universal fuel.

                  Aviation fuels are petroleum-based fuels , or petroleum and synthetic fuel blends, used to power aircraft. They have more stringent requirements than fuels used for ground use, such as heating and road transport, and contain additives to enhance or maintain properties important to fuel performance or handling. They are kerosene-based (JP-8 and Jet A-1) for gas turbine-powered aircraft. Piston-engined aircraft use leaded gasoline and those with diesel engines may use jet fuel (kerosene). By 2012, all aircraft operated by the U.S. Air Force had been certified to use a 50-50 blend of kerosene and synthetic fuel derived from coal or natural gas as a way of stabilizing the cost of fuel.

                  Jet fuel is a clear to straw-colored fuel, based on either an unleaded kerosene (Jet A-1), or a naphtha-kerosene blend (Jet B). Similar to diesel fuel, it can be used in either compression ignition engines or turbine engines.

                  Jet-A powers modern commercial airliners and is a mix of extremely refined kerosene and burns at temperatures at or above 49 C (120 F). Kerosene-based fuel has a much higher flash point than gasoline-based fuel, meaning that it requires significantly higher temperature to ignite. It is a high-quality fuel; if it fails the purity and other quality tests for use on jet aircraft, it is sold to ground-based users with less demanding requirements, such as railroads

                  Aircraft most definitely use petrol fuels.

                  • Yeah, they don't burn petrol though, as you've pretty much said so yourself.
                    • by e3m4n ( 947977 )
                      petrol = petroleum. what fucking planet are you on?
                    • Living in a bubble? Even Wikipedia redirects petrol to gasoline: https://en.wikipedia.org/wiki/... [wikipedia.org]
                    • by e3m4n ( 947977 )
                      only in your messed up country,. Usinga metric system but measuring peoples weight referencing rocks?
                      you are committing logical fallacies with universal affirmatives. Both GASOLINE and DIESEL fuels are Petrol products because petrol is a shortened word for petroleum and all fuels based on it fall under the umbrella. Its like the Family/Genus relationship to Species.

                      The Logician

                      Good evening. The last scene was interesting from the point of view of a professional logician because it contained a number of logical fallacies; that is, invalid propositional constructions and syllogistic forms, of the type so often committed by my wife.

                      'All wood burns,' states Sir Bedevere. 'Therefore,' he concludes, 'all that burns is wood.' This is, of course, pure bullshit. Universal affirmatives can only be partially converted: all of Alma Cogan is dead, but only some of the class of dead people are Alma Cogan. 'Oh yes,' one would think. However, my wife does not understand this necessary limitation of the conversion of a proposition; consequently, she does not understand me, for how can a woman expect to appreciate a professor of logic, if the simplest cloth-eared syllogism causes her to flounder?

                      For example, given the premise, 'all fish live underwater' and 'all mackerel are fish', my wife will conclude, not that 'all mackerel live underwater', but that 'if she buys kippers it will not rain', or that 'trout live in trees', or even that 'I do not love her any more.' This she calls 'using her intuition'. I call it 'crap', and it gets me very irritated because it is not logical. 'There will be no supper tonight,' she will sometimes cry upon my return home. 'Why not?' I will ask. 'Because I have been screwing the milkman all day,' she will say, quite oblivious of the howling error she has made. 'But,' I will wearily point out, 'even given that the activities of screwing the milkman and getting supper are mutually exclusive, now that the screwing is over, surely then, supper may now, logically, be got.' 'You don't love me any more,' she will now often postulate. 'If you did, you would give me one now and again, so that I would not have to rely on that rancid Pakistani for my orgasms.' 'I will give you one after you have got me my supper,' I now usually scream, 'but not before'-- as you understand, making her bang contingent on the arrival of my supper. 'God, you turn me on when you're angry, you ancient brute!' she now mysteriously deduces, forcing her sweetly throbbing tongue down my throat. 'Fuck supper!' I now invariably conclude, throwing logic somewhat joyously to the four winds, and so we thrash about on our milk-stained floor, transported by animal passion, until we sink back, exhausted, onto the cartons of yogurt.

                      I'm afraid I seem to have strayed somewhat from my original brief. But in a nutshell: sex is more fun than logic. One cannot prove this, but it 'is' in the same sense that Mount Everest 'is', or that Alma Cogan 'isn't'.

                      Goodnight.

                  • by kobaz ( 107760 )

                    He's playing semantics at this point, because in Europe and other parts of the world 'petrol' = Gas (American), specifically different than any other petroleum based fuels.

            • But long haul transportation provides use cases that favor fueled vehicles.

              That's already far better covered by overhead powered electric transport.
              And if we've learned anything from the Russian invasion of Ukraine is that you can literally run a war on rail, shipping troops and materiel across entire Asia and then doing the last mile distribution with small vans.

          • But most vehicles would do just fine with batteries...

            Majority of commutes is within 30 miles - even current batteries are more than enough...

            And future models might be fine for 95% of uses...

            Investment in hydrogen might not be worth it...

            Do you have *any* idea how much hydrogen does the chemical industry consume? It's used to make ammonia, among other things, which may be called the blood of chemical industry without much exaggeration. We *need* research into green hydrogen, not greenies calling for cuts just because it might turn out to be better than their designated winner (batteries).

            • how much hydrogen does the chemical industry consume? It's used to make ammonia, among other things, which may be called the blood of chemical industry without much exaggeration

              That's covered already. [youtube.com]
              Greener, leaner and because of that scalable up as well as down.

              • tl;dw (watch). No, not going to watch 13 minutes of some random guy's journey of self-discovery. Also, writing some chemical equations on blackboard solves nothing. Wake me up when someone builds an actual ammonia plant using this pixie-dust chemistry of his.
          • Net zero will require solutions for long haul trucking, marine and flight.

            Hydrogen, renewable fuel and fossil with compensation from air capture and sequestration are the options. Renewable fuel will als have to be made from hydrogen, given arable land limits.

            • Net zero will require solutions for long haul trucking, marine and flight.

              One of the solution, if all the scams (sorry I mean the silver bullets) we seem to discover in the recent years don't turn out right, will be less of them.

              At some point, it won't be a matter of if we agree with less or not: political instabilities, countries willing to keep their resources for themselves, are all reasons which will make it a reality. Which will impact even people who think climate change won't affect them.

              Because physics don't care about what you think or want.

          • But most vehicles would do just fine with batteries...

            No one in industry is seriously looking at hydrogen for commuter vehicles. They are looking at it for trucks, and to a lesser extent busses.
            Additionally they are looking at it to decarbonise industrial heating given how complex it is to capture carbon from many small furnaces, so even if you find a magical solution to long haul transportation or heavy industrial machinery (no batteries are no real contenders here in many cases) we'll still need hydrogen production at a large scale.

            Currently the entire world

      • Even if the hydrogen production was 100% efficient, you still need a large industrial site to make it, and then transport it to where it is used. Can't just send it down a wire like electricity.

        Sure. completely useless then. I guess your "solution" to clean air travel is to hook up our planes to wires?

        • by AmiMoJo ( 196126 )

          I'm saying that preference should be given to battery electric where possible, e.g. cars. Hydrogen cars come with many of the problems associated with fossil fuel ones, in particular that you need to distribute fuel to filling stations and then every user has to go to one regularly.

          For aircraft and certain industrial vehicles, hydrogen makes sense. How many consumer facing filling stations will remain in 20 years is anyone's guess.

          • I'm saying that preference should be given to battery electric where possible, e.g. cars. Hydrogen cars come with many of the problems associated with fossil fuel ones, in particular that you need to distribute fuel to filling stations and then every user has to go to one regularly.

            For aircraft and certain industrial vehicles, hydrogen makes sense. How many consumer facing filling stations will remain in 20 years is anyone's guess.

            No. Preference should be given to "all of them" approaches, instead of picking one designated winner. you never know which technology has a breakthrough that'll make it much better right around the corner.

  • You produce brown hydrogen.
  • I am sure we are like, green Hydrogen, so we can all get Hydrogen Fuel cell cars!
    However for consumer cars, I don't want Hydrogen Electric, I much rather have Battery Electric. It is just more practical and convenient for normal driving behaviors. Plug in every night, leave with a full charge.
    For longer trips, Hydrogen may be a little bit easier in theory, however the 250-300 mile range, and the speed of DC Fast Charging, your biology kicks in and you need to use some facilities, and your car is charged b

  • Not around here. DiHydrogen Monoxide is pretty common.

  • ho hum, another silver bullet. send me a text when it's in commercial service.

  • Just ask people using them in commercial rocket. Low energy density, embrittle metals, require lots of insulation, and also highly reactive with enviornment.

  • Pulling hydrogen off normally releases energy. Fats and oils (H-C-H chains) are to store energy. Then it's extracted again when you pull the H off.

    You're stripping the H without extracting energy here, right? You're adding energy.

    Am I missing something useful from these results? Yes, a bit of energy is needed to link the paired hydrogens afterward too. Did they lower that a bit?

    I thought hydrogenase would be a breakdown thing (versus building up again). -ase often meaning a splitting enzyme, right?

    Tha

  • It doesn't matter if you're able to produce it in a "green" way. If the process is less efficient than other competitors, and it certainly is because of physics, then it is wasting energy. We could be more green by using the inputs to do something that is more efficient. The only way hydrogen will make sense is for specific exceptional use cases or we get to a lack of scarcity with energy. That isn't happening anytime soon.

  • Not another one of those "new energy source discovered!" stories that fail to mention anything that matters like cost, scalability, efficiency, cost of implementation, etc.

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