Cheaper green hydrogen | How UK start-up Electrogenos has engineered the world’s most efficient alkaline electrolyser

A UK start-up says it has developed a low-cost alkaline electrolyser that will be able to produce 1kg of green hydrogen from just 45kWh of electricity — far lower than the standard 50-55kWh for today’s alkaline and PEM machines — significantly reducing the cost of renewable H₂ production.

Oxford-based Electrogenos says both the capital and operating costs of its unpressurised electrolyser will be lower than current top-of-the-range models, due to three proprietary cost-cutting innovations: special electroplating and stack manufacturing methods, and a novel low-cost, highly active catalyst.

“We can make the [disc-shaped stainless-steel] electrodes really cheap by electroplating, Electrogenos CEO Augusto Bartolome tells Hydrogen Insight. “Catalysts for alkaline electrolysis usually cost around $400 per metre squared, to $1,500 if you’re using platinum.

“So we’re probably looking at something around $20 per metre squared for making our catalysts. That really allows us to cut down on the cost of fabricating the stacks.”

The company utilises a “very cheap” type of electroplating, explains chief operating officer and co-founder Alfredo Saenger, declining to elaborate due to confidentiality.

“For example, we have competitors that are using plasma spraying in a vacuum-sealed chamber [to do their electroplating],” he says. “That’s a batch process with very expensive equipment. That is just not efficient. We have a very scaleable, very cheap process to plate something very delicate that will last for a very long time. And it comes because of Augusto’s [prior] experience [in electroplating and microstructures].”

Bartolome added: “We’ve also been very lucky, and we found an alloy that’s extremely active. It’s very difficult to get a catalyst that’s both active and also very durable.

“We came up with a way of making a catalyst, which normally wouldn’t work, very durable. That was the genius bit of it, we were able to unlock those durabilities.”

While the Spaniard — who has lived in the UK since his teenage years — declined to identify the proprietary catalyst material, he said it was an “alloy of transition metals”, which include iron, nickel, copper, zinc and chromium.

He added: “We’re getting much higher current densities than was traditionally possible. “We’re getting 0.5 amps per centimetre squared [A/cm²] at 1.7 volts [V], while most of our industry competitors do that at 2V. That’s a huge saving in efficiency.

“At 2V, we’re getting 1.5A/cm² — three times more than what the competition will be getting at that voltage.”

Saenger adds that Electrogenos would prefer to run its stacks at 1.7V “for greater voltage efficiency and therefore cheaper hydrogen”.

The third cost-cutting innovation is the way that Electrogenos manufactures the stack.

“The architecture of the stack is novel in that we’re able to reduce the number of parts and we use a different manufacturing technique, which allows us to be very capex efficient on terms of manufacturing,” Bartolome says.

“And this allows us to build smaller factories because we unlock economies of scale at a smaller scale.”

He explains that while other electrolyser manufacturers need to reach 1GW or more to reach economies of scale, Electrogenos can achieve its “cost-efficient point” at 200MW — which is why it plans to build multiple 200MW factories around the world to meet local demand, rather than build centralised gigawatt-scale plants like its competitors.

“I think the problem with gigafactories is that they’re labour-intensive and they’ve got to compete with China. China’s always going to have cheaper labour costs, lower than ours. So I think we have to be cleverer, we have to be smaller, linear and easier to automate. And that’s really what we’re trying to do with the 200MW factory,” said Bartolome.

“We’ve found a way of doing processes that are much cheaper and can be continuously manufactured [largely through automation].”

He added that although the company has not finalised its expected levelized cost of hydrogen, “we’re estimating we could do maybe $2/kg at [an electricity price] of $35/MWh”.

Such low renewable energy prices are already possible in sunny and windy parts of the world.

When will Electrogenos’ technology be commercially available?

Electrogenos’ electrodes and stacks are still at a fairly early stage of development, with only small versions of “a few hundred watts” having been proven in the laboratory.

“We’re looking to do a 4kW stack by the beginning of next year, then 20kW and 100kW,” said Bartolome.

“In the meantime, in Italy, we’re going to be designing and building our first manufacturing plant — and that will allow us to coat metre-squared-sized electrodes. That should be finished by the end of 2024, which means [that in] Q1 2025, we should be building our first megawatt-sized electrolyser. And we’re looking to test that with a corporate partner.

“We’ll probably do one 1MW [unit] first and then add more electrodes to do the full 5MW [electrolyser].”

Electrogenos hopes the 5MW model will be ready for sale in the summer of 2025 “if we keep on track”.

Like many start-ups, the company still needs more funding to reach commercialisation, and last month opened a new £5m ($6.3m) “seed” funding round to help fund the Italian plant, scale up the electrolysers and keep the company operating “well into 2025”.

“We raised a very good pre-seed round; we had a very supportive VC [venture capital investor] Atlantic Labs, based in Berlin,” said Bartolome. “But if we’re looking to scale our operations, we need to raise the seed round. And I think we’re at a very good position now with our technology being validated in the lab and already doing industrially relevant tests outside the lab.”

After the seed round, “if everything goes well, then we would just keep on growing with growth finance or project finance, rather than a capital risk”, he added.

Bartolome does not foresee any problems scaling up and commercialising the technology, mainly because it was designed with mass production in mind.

“We’re making sure that everything is very scalable. Our manufacturing techniques are very well understood, so that makes scale-up a lot more straightforward.

“Also, our CTO [chief technology officer] has got over a decade of experience in scaling these solutions industrially. So it is more of an engineering problem. And for that we have very good engineers in our team who are helping us take this project forward.”