Energy

Record-breaking hydrogen electrolyzer claims 95% efficiency

Record-breaking hydrogen electrolyzer claims 95% efficiency
Hysata CEO Paul Barrett with company CTO Gerry Swiegers
Hysata CEO Paul Barrett with company CTO Gerry Swiegers
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Hysata CEO Paul Barrett with company CTO Gerry Swiegers
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Hysata CEO Paul Barrett with company CTO Gerry Swiegers
Hysata's characterization of the evolution of electrolyzers, leading to the company's extraordinarily efficient new design
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Hysata's characterization of the evolution of electrolyzers, leading to the company's extraordinarily efficient new design

A kilogram of hydrogen holds 39.4 kWh of energy, but typically costs around 52.5 kWh of energy to create via current commercial electrolyzers. Australian company Hysata says its new capillary-fed electrolyzer cell slashes that energy cost to 41.5 kWh, smashing efficiency records while also being cheaper to install and run. The company promises green hydrogen at around US$1.50 per kilogram within just a few years.

Efficiency is one of the big knocks against hydrogen as we move toward a clean energy future. It can store far more energy per weight or volume than batteries, and it supports fast refueling, making it useful in applications where batteries just don't have the energy density to compete. But where batteries are a highly efficient way to store and release energy, hydrogen seems to throw energy away at every step: electrolysis, storage and transport, conversion back into electricity through a fuel cell ... Heck, it even slowly leaks out of a metal tank.

If Hysata's new electrolyzer technology does what it says on the tin, the efficiency of the electrolysis stage will take a great leap forward, making much better use of precious clean energy. And by generating more hydrogen from a given energy supply, while reducing CAPEX and OPEX expenditures for operators, this equipment could indeed drive the price of green H2 down, perhaps to a point where it becomes competitive with dirty hydrogen, or even fossil fuels.

So how does it work? According to Hysata, it's all about bubbles. Bubbles in the electrolyte fluid are non-conducting, and they can stick to electrodes and mask them from contact with the fluids they need to touch to do their work. This is clearly a problem, since electrolyzers convert water into H2 and O2 gases.

The way Hysata tells it, early electrolyzers had both electrodes submerged in electrolyte, such that bubbles would form all around them. In the 70s, zero-gap electrolysis brought the anode and cathode directly in contact with the separator membrane, boosting efficiency by only allowing bubbles to form on one side of each electrode. More recently, polymer electrolyte membrane technology allowed the cathode side to run without electrolyte, boosting efficiency again by producing hydrogen gas without bubbling it through a liquid.

Hysata's characterization of the evolution of electrolyzers, leading to the company's extraordinarily efficient new design
Hysata's characterization of the evolution of electrolyzers, leading to the company's extraordinarily efficient new design

Hysata's capillary-fed electrolyzer cell takes things to the next, and possibly ultimate, level. A reservoir at the bottom of the cell keeps the electrolyte out of contact with both the anode and the cathode until it's drawn up through a porous, hydrophilic, inter-electrode separator using capillary action. The electrolyte thus has direct contact with the electrodes, but only on one side, and both the hydrogen and oxygen gases are produced directly, without any bubbling to get in the way.

Resistance is further reduced thanks to the fact that there's no water being drawn to the side of the electrode that's releasing gas, so the two don't get in each other's way, and as the water is electrolyzed out of the separator, capillary action draws more up from the reservoir to replace it.

In a peer-reviewed paper published in Nature Communications, the Hysata team claims its capillary-action electrolyzer cell has been demonstrated at a record-breaking efficiency of 98 percent, vastly better than a "state-of-the-art [presumably asymmetric polymer electrolyte membrane] commercial water electrolyzer" which displayed a cell efficiency of 83 percent. Gas crossover is extremely low – this is critical, since at the right temperatures and concentrations, a hydrogen-air mix can be explosive.

The company says this technology cuts down on extraneous expenses outside the cell as well. There's no need for liquid circulation, gas-liquid separator tanks, piping, pumps and fittings. This gear can be air-cooled, or radiatively self-cooled, cutting down further capital and operating costs, and should the gravity-limited maximum height of the capillary action prove to be a limiting factor, well, Hysata says you can just pop the reservoir tank on top and have the electrolyte run down the separator instead.

All these factors help to cut down "balance of plant" energy use outside the electrolyzer cell, putting an even bigger gap between this technology and others when looking at overall system efficiency.

"Hysata’s overall electrolyzer system has been designed for ease of manufacturing, scaling and installation, delivering 95 percent overall system efficiency, equivalent to 41.5 kWh/kg, compared to 75 percent or less for existing electrolyzer technologies," said company CTO Gerry Swiegers in a press release. "For hydrogen producers, this will significantly reduce both the capital and operational costs to produce green hydrogen."

Swiegers goes on to call this device, "an entirely new category of electrolyzer that is as monumental as the shift from the internal combustion engine to electric motors."

Hysata CEO Paul Barrett says the company plans to have the technology commercialized and up to "gigawatt-scale hydrogen production capacity by 2025," at which point he believes US$1.50 per kilogram hydrogen should be possible. Plans are underway to build a pilot electrolyzer manufacturing plant, and the company is hiring "dozens" of people in 2022 as part of the process.

Hydrogen production is expected to skyrocket in the coming years as green H2 finds its place in the tougher sections of a new green energy economy. So there's definitely a gold rush on, and many expect a squeeze on electrolyzer production as producers race to get their facilities up and running. Under such circumstances, a cheaper, super-efficient electrolyzer will certainly find itself in huge demand, so Hysata might have a monster product on its hands and a chance to make an impressive contribution to the fight against climate change.

Of course, there's a long race to be run between a published paper and massive commercial success, but with potential upsides like Hysata is claiming, this is clearly a company to keep an eye on.

The research is published in the open-access journal Nature Communications.

Source: Hysata

10 comments
10 comments
Bart Hibbs
I notice for the efficiency values they use Hydrogen's Higher Heating Value, not the Lower Heating Value of 32.43 kWh/kg. Fuel cell efficiencies are always quoted relative to the LHV. Remember that when you do the round trip efficiency math. At least this does help Hydrogen's cause, a little.
If the water has a few impurities, how do they get flushed out?
BeholdersEye
My fear with a large production of needed hydrogen gas, there will also be a higher loss of hydrogen, and since the earth gravity is not great enough to retain the unbonded hydrogen to Earth, this gas is gone for good if released, never to cycle back into the atmosphere...'drying up' the source eventually in the future...
Pankaj Gupta
Would it imply that hydrogen liquid would be the best battery for energy storage
Alexander Cokonis
With the lower cost of solar or wind electricity green hydrogen can easily be produced at around $3/kg. It’s overall efficiency relative to ICE engines is approximately 2.5 times better. It’s equivalent to running your car at $1.20 per gallon. The other advantage is the range and fill up time is comparable to ICE vehicles. The versatility of hydrogen is immense, it can run any type of engine, power rockets, create synfuels to power jet planes and fertilise biofuels and minimise fossil fuels for a cleaner environment. You can also store it forever with proper materials.
DaveWesely
Excellent comment Bart. It seems we should also be considering where these hydrogen electrolyzers will end up. A lot of wind turbines should end up on the Great Plains in the US. Not many people, but a lot of wind generation capability. Since wind has a lot of variability, the DC - AC inverters to send power to the grid are rated less than the maximum turbine output. Probably about 25%. So you see some turbines spinning while others are stopped. The excess is used to charge batteries, but not much else. Hydrogen electrolysis could be applied here, onsite, without inverting to AC and sending to the grid. The hydrogen could be sold, or better yet, converted to anhydrous ammonia (NH3) for fertilizer right there on the farm. Or sold for fuel/fertilizer.
Ironically, this could be the best thing to happen economically here in a long time. But instead a lot of the farmers and ranchers have fallen for the fossil fuel anti-renewable energy propaganda.
Nobody
I don't understand the enthusiasm for hydrogen. It is explosive anywhere from 10-90% with air. It is too dangerous to be handled as a liquid or a gas without extreme precautions. It can diffuse through steel tanks potentially forming explosive gas pockets in confined storage areas or just lost to the atmosphere. It will have to be stored as a hydride in a vehicle fuel tank that won't detonate like a stick of dynamite in an accident. I think even EVs will diminish in popularity after a few people get electrocuted or fried in a battery explosion. High energy density is great but at least fossil fuels are relatively safe by comparison. I've read that there are 80 or so car models in the world that get over 50mpg that are illegal to sell in the U.S. for safety reasons but you can buy a motorcycle or scooter. I have been waiting for generator trailers to be introduced which can recharge all electric cars on longer trips. Essentially making electric cars hybrids on long trips and strictly electric on short trips. Or just buy a hybrid and plug it in every night. I think they already did that.
madsci
If the efficiency is as good as stated, one could convert the hydrogen into methanol using CO2 in the process as George Olah has proposed in the "Methanol Economy". Methanol could be easily transported and used in our current infrastructure. The main issue to overcome is the toxic nature of methanol and its miscibility with water (need to be careful of leaks/spills that could contaminate drinking water).
Leo Petipas
Normal bill paying consumers--who use the dollar-- are used to seeing the rate cents/kWh. I guess we need to do the simple math ourselves. Promising news though.
Brent Massmann
It appears that there are dubious claims being made. The theoretical voltage required for water hydrolysis is 1.23 V at 298 K. The cell described in the article operated at about 1.5 V and used hot water at 358 K. This can not be rigorously defined as 95% efficiency. What looks like an interesting invention has lost credibility because of a clumsy attempt to spin and promote the results as 95% efficient instead of an objective evaluation of the results which appears to be about 80% efficient., which is a very good result given that over voltage is always required to reach the activation energy of the reaction.
Philip
$1.50 to make 1 Kg of hydrogen requires 41.5 kWh as stated. The cost of electricity is then $1.50/41.5 kWh = $0.0361 per kWh. My electricity costs more like $0.13 to 0.16 per kWh. Where can I get electricity for 3.6 cents per kWh? Even electricity bought industrially costs more than 3.6 cents per kWh.