Nova Scotia researchers help put the pieces of the green hydrogen puzzle together

In a lab tucked away on the fourth floor of Dalhousie University’s Chemistry Building, Associate Professor Mita Dasog points to an illuminated tube containing a brown liquid, which researchers hope will help society shift away from fossil fuels.

The tube represents part of the laboratory’s work on the production of green hydrogen by artificial photosynthesis.

« We’re basically trying to mimic what plants do, » says Dasog.

It’s part of a range of research the lab is undertaking which also includes research into ways to cut costs, as well as working with « alternative technologies ».

The provincial and federal governments have set ambitious targets for the production of green hydrogen. The federal government plans to begin shipments of green hydrogen to Germany by 2025. Nova Scotia aims to begin granting leases in 2030 for offshore wind that would support green hydrogen production.

But even as interest in green hydrogen grows, advocates and researchers say there are still hurdles to overcome before the promise to support the energy transition can be delivered.

The cost problem

Almost all of the hydrogen currently produced in Canada comes from fossil fuels — so-called “grey” and “black” hydrogen — which contributes to greenhouse gas emissions.

But it can also be made from water, using electricity to split molecules into hydrogen and oxygen through a process called electrolysis. When this electricity comes from renewable sources, the result is known as green hydrogen.

But producing it is expensive, says Dasog. The cost is about three times that of gray hydrogen, in part because precious and rare metals like platinum and iridium are used in electrolysis. Dasog’s lab is therefore studying materials that have the same properties but are more abundant, which would reduce the cost.

After looking at « hundreds and hundreds of materials, » Dasog says, they found a cheaper alternative that works just as well as platinum.

One of the current limitations of green hydrogen is that it requires significant amounts of energy to produce. (Andrew Vaughan/The Canadian Press)

But the lab’s work focusing on artificial photosynthesis could cut costs in another way — by eliminating the need for electricity altogether.

This approach uses what is called a photocatalyst. In Dasog’s lab, they use silicon materials that are thinner than a billionth of a meter in diameter and absorb sunlight like plant leaves do. These tiny photocatalysts can be suspended in water, or painted or printed on a surface, and react with the surrounding liquid.

“We can use sunlight directly, just like plants do to separate water to produce this hydrogen,” she says. « So we’re removing the capital costs associated with power generation. »

Dasog lab graduate student Sarrah Putwa poses with an artificial photosynthesis facility the lab uses to produce green hydrogen.
Graduate student Sarrah Putwa at work in the Dasog lab. It focuses on ways to improve the longevity of silicon nanoparticles used in a process that produces green hydrogen through artificial photosynthesis. (Moira Donovan)

Sarrah Putwa is a graduate student in Dasog’s lab working on improving the longevity of nanoparticles, which would make the technology more versatile.

“We could run water over a bed of these photocatalysts, and there would be hydrogen produced,” she says.

Putwa is from Tanzania, an East African country highly vulnerable to the effects of climate change, and says she is driven by the potential of technology.

« Working on a project that enables production in a sustainable way, I understand that will not solve the energy crisis, but it certainly plays an important role in mitigating it. »

While a similar approach has been used in a pilot project in Japan, artificial photosynthesis does not yet exist commercially. Part of the problem, says Dasog, is that there has been a lack of investment in the field, a challenge that was also identified in the federal government’s report. hydrogen strategy.

« Now there’s a sudden interest and people want these mature technologies that unfortunately don’t exist, » she says, « they haven’t been able to get from lab to market because we haven’t had the mechanisms funding to do so ».

Renewable energies « should be a priority »

Some advocates say the federal and provincial focus on developing green hydrogen for export also ignores another part of the energy transition: using renewables to power the grid directly.

Brenna Walsh, energy coordinator at the Ecology Action Center in Halifax, says green hydrogen could help address the intermittency of renewables. For example, by using wind power to generate hydrogen when excess energy is produced, this energy could be stored when the wind is not blowing.

But producing green hydrogen is a less efficient use of renewable energy than simply directing that energy to the grid, Walsh says.

Giant wind turbines are seen off the coast of Sussex, England in September 2017. Wind power could help fuel hydrogen production. (Mike Hewitt/Getty Images)

“We currently have a 50% network [fuelled by] coal. And so if we can have this renewable energy that directly replaces fossil fuels, that’s something that should be prioritized,” she says.

“Focusing on the kind of renewables in place – wind and solar – and how we can get them onto the grid efficiently, I think should be a higher priority.”

Nonetheless, Walsh says hydrogen still has a long-term role in hard-to-decarbonize sectors, such as fertilizer, aviation, shipping and long-haul trucking.

Storage, transportation issues

Some of the research being done in Dasog’s lab could be applied in these contexts. One example is a hydrogen-from-powder project that received funding from Innovacorp to scale up to commercial scale.

This could facilitate the transport and storage of hydrogen.

Because hydrogen is a gas, it occupies a large volume. Export projects have been proposed in Nova Scotia to convert it to ammonia or to compress it, but both of these processes require energy.

Companies have also secured licenses to explore the use of Nova Scotia’s salt caverns for storage, and the province recently amended the Underground Hydrocarbon Storage Act to include hydrogen.

Sarah Martell, a doctoral student at the Dasog laboratory, presents a configuration that produces hydrogen on demand through the use of silicon powder.
Sarah Martell, a doctoral student at the Dasog laboratory, is working on a process for producing green hydrogen on demand from silicon powder, water and a base material. No electricity is needed. (Moira Donovan)

Research at Dasog’s lab offers another type of storage solution – using powdered silicon to generate hydrogen through a chemical reaction as needed.

« It’s hydrogen, but in a different form, » explains Sarah Martell, a doctoral student at the Dasog laboratory who studies hydrogen on demand. « It’s easier to carry around a jar of this brown powder than lugging around a tank of gas, for example. So, paired with a portable fuel cell, you can get power whenever you need it. «

Martell says they’ve tested the process to show it works just as well with Halifax Harbor water as it does with tap water.

The silicon itself could be made from a variety of sources – such as sand, recycled packaging or cereal husks – allowing it to be adapted to the local context.

« We don’t want one region to have a monopoly on this material, » says Dasog.

It could be used to power light vehicles, as a power source in remote areas or in emergency situations.

With this and other ways to produce green hydrogen, Dasog says it’s important to remember that it’s not just a fuel, but a way to help others. sectors to decarbonize.

« It’s going to impact a lot of different industries, and I think it’s important to highlight that because the reach is quite broad and the opportunities are quite broad. »

And while green hydrogen alone won’t solve the energy crisis, Dasog says, the innovations his lab is working on could be part of the puzzle.

« We really need multiple solutions. »


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