An overcommitment to any single production technology at this early stage of the hydrogen economy could stymie its long-term prospects and hinder its role in decarbonization, government and industry stakeholders warned Dec. 2.
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"It's crucially urgent that we start to get hydrogen into the system," said Varun Sivaram, senior director of clean energy and innovation under US Special Presidential Envoy for Climate John Kerry, said during an Atlantic Council panel discussion. "That said, there is a risk that if you scale up a technology today super quickly, you make it more difficult for the technology of tomorrow to eventually break into the market. It's important that we're aware of that," Sivaram said.
Although there are a variety of ways to separate hydrogen from water molecules – each with its own carbon intensity levels – a select few have come to the fore. Polymer electrolyte membrane, or PEM, electrolysis and alkaline electrolysis are common methods for producing green hydrogen using renewable energy. Natural gas is also a common feedstock that can lower hydrogen's carbon intensity when paired with carbon capture technology, known as blue hydrogen, than when it's not, known as grey hydrogen.
Falling within the second tier of hydrogen production technologies is a range of methods with more modest levels of deployment. Pink hydrogen, for instance, is generated using nuclear energy, and turquoise hydrogen uses a methane feedstock to produce hydrogen with a sold carbon byproduct usable in other applications.
But just because some technologies are ahead of the curve does not mean that they should receive exclusive support from government subsidies and industry investments, Sivaram said. Despite attention PEM and alkaline electrolysis often receive for their low carbon intensities, Sivaram questioned whether the technology that will unlock hydrogen's greatest potential is yet discovered.
"It's not obvious to me that the technology that we will want to produce hydrogen in 2050 is in fact there right now," he said. "Maybe it is – maybe it is the case that the alkaline or PEM electrolyzer that we have today is what we will scale up and enable us to decarbonize steel and aviation. But maybe not."
"I think there is still a lot of opportunity for technology to ferment," Sivaram said.
One example of technological fermentation comes from the recently announced partnership between the renewable energy technology company Heliogen and electrolyzer maker Bloom Energy to produce hydrogen using concentrated solar combined with high-temperature electrolysis – a method the companies claim can produce hydrogen 45% more efficiently than PEM and alkaline electrolysis.
Microwave plasma rectors
Jillian Evanko, CEO of Chart Industries, a hydrogen liquefaction technology company, says that her company invests in multiple different start-up technologies without being married to electrolysis technology. One such technology Chart Industries is investing in involves producing hydrogen using microwave plasma reactors.
"There's other technologies to make the molecule, and that's where this evolution is starting to go,"Evanko said. "I think the conversation should get away from electrolysis to what's the most effective way to make the molecule."
According to Platts price assessments, the cost of producing hydrogen using PEM electrolysis (including capex) in Southern California was $4.48/kg on Dec. 1, while the cost of producing hydrogen using steam methane reforming (including capex) without carbon capture was $1.41/kg.
Prices are slightly lower in the US Gulf Coast region. Hydrogen produced using PEM electrolysis cost $3.91/kg while hydrogen produced using steam methane reforming without carbon capture cost $1.14/kg.