The amount of renewable energy needed to produce green hydrogen will be enormous. Just replacing all the polluting grey H2 currently used in the world every year will require almost twice as much green power as installed globally today.
What if there was another zero-carbon method of producing green hydrogen that did not require electricity to split water molecules? Even better, what if that process actually produces electricity at the same time?
A US start-up says it has developed just that.
Pennsylvania-based GenHydro has developed a method of producing zero-carbon H2 from scrap aluminium, in a process that extracts hydrogen from water molecules while at the same producing heat that can be used to turn steam turbines that produce clean electricity.
How does the process work?
Aluminium is an oxygen-hungry metal — as soon as you produce it and expose it to air, a thin layer of aluminium oxide (also known as alumina or AlO) naturally forms on the surface.
It is this oxide layer that prevents every-day aluminium from reacting with water.
However, if pure aluminium could be exposed to water before air, oxygen molecules would quickly bond with it to form AlO, releasing hydrogen molecules in the process.
But removing that layer of alumina is not easy. Previous attempts involving concentrated sulphuric acid did little more than eat through water tanks.
GenHydro has, however, found a way of removing that surface oxide layer from aluminium alloys using a “promoter” catalyst inside a stainless-steel reactor, thereby allowing the aluminium to work its magic in water.
“The secret’s in the internal components of the reactor, the promoter and the thermodynamic conditions,” GenHydro CEO Eric Schraud tells Hydrogen Insight, declining to give further details of the company’s “secret sauce”.
“There’s various types of alloys that we can use, as long as it’s 95% aluminum,” he says, using the American version of the word.
He points out that finding scrap aluminium alloys is not hard. “It’s everywhere — I’m sure the chair you’re sitting on right now has an aluminum frame. [It’s in] fences, windows, aluminum siding on homes, aluminum cans…”
Nine million tonnes of aluminium gets landfilled in the US each year — which Schraud says could produce about one million tonnes of clean hydrogen annually.
He explains that GenHydro treats and washes the scrap aluminium before milling it into a fine powder — using renewable energy, or electricity produced using the heat from the reactor process.
“And then now it’s ready to get pre-mixed with a promoter and go into our reactor.”
Schraud says that in the GenHydro process, every metric tonne of aluminium produces 111kg of hydrogen and 3.12MWh of electrical energy from the steam turbine.
And GenHydro is currently buying aluminium scrap at a cost of $700-800 per tonne.
But the cost of the hydrogen is not only offset by the electricity production, but also by the by-product alumina — a “slurry” that forms at the bottom of the reactor, which is used in advanced ceramics and can be sold for up to $7/kg, depending on how it has been processed.
“Our process breaks [the alumina] down at the molecular level, and so you actually end up getting nanoparticles coming out… [which] is great, because you get advanced characteristics.
“[Alumina] is on Abrams tanks, grinding wheels, ballistics-grade aluminum glass [and] bulletproof vests.”
It can also be used to produce low-carbon “geopolymer” cement made from alumina and sand (silicon oxide), rather than the calcium oxide that forms Portland cement.
When taking into account the sale of the by-products — electricity and alumina — and the fact that the reactor works around the clock, rather than relying on a variable renewables supply, the resulting hydrogen is “a lot cheaper” than green H2 produced by electrolysers, Schraud says.
And because no CO2 is emitted in the production process, the H2 would be eligible for the highest level of US hydrogen tax credit under the recent Inflation Reduction Act — $3/kg, further reducing its production cost.
Schraud also points to the efficiencies of the process.
“We’re pulling out 72% of the energy that it took to make that scrap aluminum, which has had a useful life, and then creating three commodities with it and distributing diverse fuels,” he says.
A single modular reactor — which “roughly has the footprint of a Coca-Cola machine” — produces 25kg of hydrogen an hour, along with 780kWh of electricity. Reactors and the balance of plant equipment (eg, steam drums, turbines, water tanks and hydrogen dryers) are provided on shipping-container-sized “skids” that can be linked in series to make as much hydrogen and clean electricity as the customer wants.
Schraud explains that the start-up’s business model is to “co-site” its modular equipment at a customer’s facilities — which has several benefits.
GenHydro will own the equipment, while providing aluminium alloy powder pre-mixed with the promoter chemical and also collecting the alumina slurry.
“We think it’s better to distribute a solid fuel than it is to distribute hydrogen,” he says, mentioning the ability to transport the aluminium using “standard shipping rates”.
The customer will get 24/7 clean electricity at near-wholesale prices and green hydrogen on site through 10-15-year purchase agreements with GenHydro. By locating the equipment where the H2 is used, it removes the need to compress or liquefy the hydrogen or pay the high costs of transporting the gas.
“We might train an operator there, but then we monitor remotely, just like most traditional power plants. We own the tech, we don’t sell it, we just sell what comes out.”
One of the beauties of this business model, Schraud explains, is that there are no upfront costs for the customer.
“We get the financing for the capital expense to do the install, and then we amortise it over the life of the unit. The customer doesn’t have to do any upfront investment, they just switch providers. It removes a ton of friction and it makes it so easy for them.”
Schraud tells Hydrogen Insight that it currently has seven customers in its pipeline, including a contract lined up with a “huge US auto manufacturer” to build a pilot plant in January at its UK factory, which will then be expanded to 3.5MW in June next year, then 17MW and eventually 26MW (measured in terms of electrical power output).
“Our smallest [commercial] project right now is 5MW... and we have projects as large as 300MW. It’s a huge range and it’s kind of dependent on the availability of regional supply of aluminium scrap,” he says.
Schraud explains that one of the seven customers became interested in the GenHydro technology because it wanted round-the-clock green electricity, but now they want to convert their forklifts and vehicles to make use of the clean hydrogen too.
The hydrogen could also be converted into electricity using a fuel cell, “so they get back-up energy, grid-level [energy] storage, essentially”, he says.
Schraud says that the company’s first “commercial project” will be built in the third quarter of 2023 at its own headquarters in Lancaster, Pennsylvania, providing clean electricity to itself and a neighbouring company.
“Since this is an emergent technology and it’s very new, we’re running the pre-commercial installation here, and demonstrating commercial viability by powering ourselves and another customer locally. We’re running these projects, we’re running pilot phases first, and then we’re going to scale and ramp up,” he explains.
The size of the potential market for GenHydro is vast, limited only by the supply of scrap aluminium.
Schraud says he could see GenHydro supplying customers around the world with tens of millions of tonnes of hydrogen per year and “several hundred thousands gigawatts of electrical energy”.
“Just the seven projects we have in our pipeline — 50 reactors, 54MWh an hour... we’re already into the gigawatt hours, were already into the tens of tonnes of hydrogen with the projects we have now,” he explains.
“I could see our solution really shining and providing a significant portion of the hydrogen to the mobility space, and then also making a significant dent into the industrial electrical power space.
“I mean, it’s hard to say where we’re going to be [in the future] because the market potential’s so immense.”
Eric Schraud co-founded GenHydro with his brother Matt (now chief marketing officer) in early 2021, after many years of “moonlighting as a chemist and physicist” in his spare time, and working with “random people along the way”.
His day job was as a business consultant for Ernst & Young in New York City, before later becoming the CEO of a cabinet-making company in Lancaster, Pennsylvania.
“I was always very technical and I just kind of had an interest in science — so I started tinkering,” he tells Hydrogen Insight. “It was my own personal money, my own finances. And then there were engineers from institutions that I would [speak to and] pick their brains along the way.
“And when we started to see some actual results, then we started to formalise [a new business].”
The company was initially funded through a “friends and family” investment round, but has recently opened a Series A funding round.
“We try to be careful with some institutional investors, because some of them can be a little aggressive with their terms. We’ve been trying to stick with high-net-worth individuals or other organisations that would strategically partner with us, because then we get a little more solidarity, and a little bit more like a team.”