Natural gas has held a tight grip on the global hydrogen supply for decades, and gas stakeholders are looking forward to more where that came from. Nevertheless, green hydrogen from renewable resources is beginning to push its way into the market. Costs are relatively high now but green hydrogen is new industry with room to foster economies of scale, supply chain efficiencies, and new technologies.
The Long Road To Low Cost Green Hydrogen
Hydrogen is grease for the wheels of modern industrial and agricultural economies, but it also shackles economic activity to natural gas and other fossil resources. About 95% of the hydrogen produced in the US, for example, comes from natural gas.
The US Department of Energy has set a goal of reducing the cost of “clean” hydrogen to $2 per kilogram by 2026 and $1/kg in 2031, which is a steep drop from the 2020 baseline of $5/kg (in addition to various non-fossil sources, the Energy Department includes natural gas with carbon capture under the “clean” umbrella, which also impacts costs).
Skeptics have scoffed that the cost-cutting goalposts are unrealistic. Bloomberg NEF is not one of them, though NEF did run the numbers last August and the picture was not pretty. They calculated the cost of producing hydrogen from fossil resources, without carbon capture, at a range of $0.98-$2.93/kg. Adding carbon capture boosted the cost to $1.8-$4.7/kg, but that still left green hydrogen behind in the dust.
“And green hydrogen, which is produced by running an electric charge through water, costs a whopping $4.5-$12 per kilo[gram],” NEF reported.
However, that’s just the here and now. NEF took a look at the near future and calculated that green hydrogen would beat fossil-sourced hydrogen in an increasing number of major global markets beginning with Brazil, China, India, Spain and Sweden.
Many Roads To Green Hydrogen
In terms of cutting costs, one key breakthrough for green hydrogen emerged in recent years as the cost of wind and solar power began to drop. That has had a significant impact on both the economic and environmental cases for electrolysis systems, which deploy electricity to jolt hydrogen loose from water (check out our hydrogen archive here).
Water electrolysis has been cropping up regularly on the CleanTechnica radar, though we’ve also taken note of photoelectrochemical cells, microbial fuel cells, and other alternatives that produce hydrogen without relying on natural gas.
Pushing Down The Cost Of Electrolysis
Scale-up and supply chain development are two important levers for driving down the cost of electrolysis systems. Technology innovations are also coming into play. With that in mind, let’s look at the idea of combining electrolysis with other systems to extract hydrogen from renewable resources.
Back in 2013 CleanTechnica took note of a green hydrogen project at a wastewater treatment plant in California that paired the US Department of Energy’s Lawrence Livermore National Laboratory with the startup Chemergy to produce hydrogen from the organic material in municipal wastewater.
The soup-to-nuts experiment was conducted at a wastewater treatment plant in California, supported with hydrogen fuel cells developed by the US Department of Defense. The end goal was to use the fuel cells to produce electricity to run the treatment plant.
Instead of starting with electrolysis, the Chemergy system begins with a reactor step that produces hydrogen bromide gas. The gas is introduced to water, producing liquid hydrobromic acid. The liquid is finally run through an electrolysis system similar to those used in producing chlorine.
If you’re wondering why not use just plain water for electrolysis, that’s a good question. The bonds in hydrobromic acid are much weaker than those in plain water, enabling the electrolysis system to run more efficiently. That caught the eye of the Halliburton Labs, which tapped Chemergy as one of three companies to participate in its accelerator program last year.
Chemergy has also extended its waste stream to include soiled plastic waste and other materials, and they are currently commercializing their proprietary HyBrTec hydrogen system on an energy-as-a-service model.
Calming The Iridium Membrane Panic
Bringing down the cost of electrolyzer membranes is another area of focus. The stumbling block is iridium, a rare precious metal favored by the electrolyzer industry as reaction-inducing catalyst for membranes.
“Iridium has emerged as one big, fat stumbling block along the road to low cost green hydrogen. Iridium oxide catalysts take care of the the oxygen-producing side of electrolysis in a polymer electrolyte membrane (PEM) electrolyzer system,” CleanTechnica noted earlier this month.
“Despite the high cost and limited supply, PEM stakeholders prefer iridium due to its energy efficiency, stability, and durability,” we added.
Not for long, if all goes according to plan. Researchers have been focusing on ruthenium as a cost-cutting alternative catalyst. A team at Rice University team in Texas, for example, has reported encouraging results for a a nickel-doped ruthenium oxide catalyst.
Look Ma, No Membrane
Yet another solution came across the CleanTechnica radar last week, when the Welsh gas company Wales and West Utilities emailed their latest news to us.
“Wales & West Utilities is partnering with global hydrogen company, HydroStar, to produce the innovative electrolyser prototypes, which use unpurified wastewater from processes or rooftops to reduce the cost and impact of green hydrogen,” they said. “The technique will remove rare metals from the design and use a green, non-corrosive electrolyte which can be adjusted to suit specific types of wastewater.
That’s quite a lot to digest, so to speak. However, research into membrane free electrolyzers has been moving along at a rapid clip, and Hydrostar is among the firms ready to bring the technology to bear on green hydrogen.
The plan calls for Hydrostar to produce three types of membrane-free electrolyzers for Wales and West, focusing on water with various kinds of impurities, including rainwater runoff, storm overflow, and industrial wastewater.”
Hydrostar is playing it close to the vest regarding its proprietary B9™ electrolyte solution, except to note that the ingredients meet the safety standards of the US Federal Drug Administration and European Union, as well as other environmental and health standards globally.
The UK-based firm is already marketing a 50-kilowatt, solar-compatible, membrane free electrolyzer system under the name HydroSol. The out-of-the-box modular units can be linked form 1-megawatt pods, which can be combined to form 100-megawatt arrays.
Meanwhile, the project with Wales and West is scheduled to culminate next March, so keep an eye on that.
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Photo credit: Modular system for producing green hydrogen with solar power courtesy of Hydrostar.
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