Researchers at the University of Alberta and University of Toronto have found a way to produce the greenest and cheapest hydrogen, a finding that would help retool Alberta’s energy sector and push the province closer to a net-zero future.
Erin Bobicki, a mineral processing researcher in the U of A’s Faculty of Engineering who specializes in processes for extracting valuable minerals and metals from ores, has spun a technology that uses microwaves to create hydrogen — a valuable industrial feedstock and critical piece of the province’s sustainable energy future — into a startup called Aurora Hydrogen.
Last fall Bobicki was approached by Murray Thomson, a University of Toronto professor and expert in the process of using methane to generate hydrogen, who was wondering whether microwaves could be used to make the process more energy efficient.
“Microwaves are a very efficient way to transmit energy to materials,” said Bobicki. “There's a lot of interest in hydrogen, and a lot of the processes for generating hydrogen are extremely energy intensive.”
Currently, hydrogen is being used in the province mainly for upgrading oilsands bitumen, a heavy viscous material that requires hydrogen to produce products like gasoline or diesel fuel. Oilsands companies use upwards of 10,000 kilograms per hour to upgrade their carbon-heavy bitumen.
Aurora’s bench-scale reactor can make two kilograms of hydrogen per day, but could easily scale that up to 200 kilograms per day — enough for a fuelling station in a remote community — using a larger, commonly available microwave generator.
“Most other technologies can either produce hydrogen at a small scale or produce hydrogen at a very big scale; for us there's no fundamental limit on the scale,” she said.
What Aurora’s technology does, according to Bobicki, is not unlike what a microwave in a home does. Methane, the main ingredient in natural gas, is heated indirectly using microwaves, creating hydrogen and solid carbon. Because the carbon does not become a greenhouse gas, the resulting emissions are lower than even the greenest current hydrogen-producing processes.
At the greenest end of the hydrogen spectrum
Those processes are classified according to a colour-coded system based on carbon footprint that ranges from the least sustainable grey to most sustainable green.
“Grey hydrogen” is made from the steam methane reforming (SMR) of natural gas to “crack” the methane into hydrogen and carbon dioxide. This process results in emissions in the range of nine kilograms of CO2 per kilogram of hydrogen produced.
“That's how big hydrogen producers and consumers would typically do it,” said Bobicki.
The next level is “blue hydrogen,” which is only different from grey in that producers employ carbon capture and storage to reduce GHG emissions by 90 per cent.
“Green hydrogen” uses electrolysis, or the splitting of water molecules, and is very clean in principle, but Bobicki explained it is extremely energy intensive because the bond between hydrogen and oxygen is strong.
“And if you use perfectly clean renewable electricity, then in theory you could have zero CO2 emissions. But in reality there's a lot of carbon in the grid in most jurisdictions, and so the footprint is actually pretty big.”
Electrolysis of water to make green hydrogen needs 193 megajoules of electricity per kilogram of hydrogen. Aurora’s technology, which is considered a “turquoise hydrogen,” requires only 35.
“Our process uses 80 per cent less electricity than green hydrogen, and the modelling work we're doing is showing that we have a lower greenhouse gas footprint than any other form of hydrogen production in most jurisdictions,” said Bobicki.
“The electricity demand is really where the rubber hits the road because it makes such an impact in terms of energy demand and greenhouse gas emissions.”
Even the carbon powder byproduct has value, whether it's used in the creation of items like tires and soil additives or in steelmaking as an alternative for coal.
“From a business perspective, in the short term, it makes sense to sell the carbon before ultimately sequestering that carbon and collecting credits.”
And with dozens of countries pledging to be carbon neutral by the middle of the century, Bobicki said the demand for hydrogen is set to skyrocket from $190 billion to $2.5 trillion over the next three decades.
“Electrification is going to dominate in many areas for decarbonation, but hydrogen is a really nice fit where a chemical fuel is required.”
As for the next step, Aurora is fundraising for a scaled-up pilot project and is hoping to bring this product to market as quickly as possible.
