Researchers study how Earth’s smallest molecule could play a big role in our energy future

Three UCalgary research projects have received funding from Alberta Innovates Hydrogen Centre of Excellence to advance innovations in the hydrogen energy domain. The projects will help researchers understand and de-risk the creation of a clean hydrogen economy in Alberta.

Why hydrogen? Hydrogen is the most abundant element in the universe and can provide energy without releasing carbon dioxide (CO₂), which means it has the potential to be a major contributor to clean energy supply. It can be derived from the chemical conversion of natural gas or through electrolysis of water, and when burned for energy or used in a fuel cell it only emits water.

But hydrogen use doesn’t come without complexity and risks. While abundant, it is also the smallest molecule on Earth, meaning it is easy to lose through leakage when stored. If a hydrogen leak goes undetected in a small space, like a basement, there is potential for asphyxiation. When used as fuel, hydrogen is also highly flammable and can be explosive.

It’s the goal of three UCalgary research groups to learn how we can mitigate these risks through research, and make hydrogen a safe, efficient, and cost-effective alternative energy option in Alberta and around the world.

The projects are led by Dr. Frank Cheng, PhD, and Dr. Simon Park, PhD, professors in the Schulich School of Engineering; and Dr. Casey Hubert, PhD, professor in the Faculty of Science.

Possibility of using pre-existing pipeline infrastructure

“One of the big challenges for the hydrogen economy is infrastructure, and how we deliver cost-effective hydrogen supply,” says Park. “We believe that one of the solutions is utilizing existing natural gas pipelines.”

Cheng and Park, both members of the Pipeline Engineering Centre, will investigate two different aspects of pipeline use for hydrogen. Cheng’s team will develop a technique to assess the suitability of existing pipelines for hydrogen transport, while Park’s team will investigate the behaviour of hydrogen in pipelines.

“The existing pipelines have been in service for many years or even several decades,” says Cheng. “Various defects such as dents and corrosion exist on the pipe body.

“These defects could become locations to accumulate hydrogen atoms, resulting in initiation of hydrogen-induced cracking, known as hydrogen embrittlement.” Hydrogen can escape through the smallest crack in a pipeline, creating opportunities for dangerous and potentially costly leakage to occur.

Cheng will develop a technical assessment protocol that can be used to determine the susceptibility of existing pipelines to hydrogen embrittlement in high-pressure hydrogen gas environments.

Risk assessment for hydrogen use in homes

Park’s project is examining how hydrogen behaves when moving through pipelines, based on scenarios where hydrogen is mixed with natural gas to be used as a mixed fuel in homes. This practice reduces use of natural gas and the resulting CO2 emissions, without having to change residential furnaces and appliances.

“We want to understand the behaviour of a mixture of hydrogen and natural gas so that people can have a proper risk assessment,” says Park. Park and team are looking at how the hydrogen and natural gas separate in pipes, and how that impacts their flow into homes.

A potential side effect of mixing hydrogen and natural gas is the loss of the efficacy of natural gas’s built-in ‘alarm system’. Natural gas has a stinky sulphur compound additive in it, so that you notice a rotten egg smell if you have a gas leak in your home.

Park and team are investigating the behaviour of the odorous additive in the blended hydrogen and natural gas, to determine if the smell is noticeable in the instance of a leak.

To further reduce the risk of using hydrogen in homes, Park and team are developing sensors to measure hydrogen moving through pipes, as well as cost-effective sensors to detect hydrogen leaks in the air of a home, like a smoke or carbon monoxide detector.

“There’s a lot of hydrogen to be used in Alberta,” says Park. “It's important to have good transportation and safety measures, and that's what we are trying to achieve.”

How to store a small — and delicious ­— molecule

If we’re going to use hydrogen in this way, and at very large scale, we will need to store it somewhere prior to distribution. One option being considered for storage is salt caverns deep under the earth’s surface.

The most common concern about storing hydrogen in these geological formations is leakage, because of the molecule’s small size. But Hubert, a microbiologist, is more concerned about hydrogen’s other important property: how delicious it is for micro-organisms.

“The bacteria knew how effective hydrogen is for fuel, millions and likely billions of years before we did,” Hubert says. “They've been eating hydrogen the whole time.”

Hubert’s team specialize in the study of the deep biosphere, and the micro-organisms that live there. They will investigate what types of microbes are present in the salt caverns, how much hydrogen they could consume and whether any adverse byproducts could be produced.

Hubert calls this “finding out if the bugs are going to eat our lunch” — essentially, trying to understand if microbes pose a threat to our ability to efficiently store hydrogen, and how costly that threat could be.

The potential cost isn’t just the loss of the hydrogen to the microbes’ insatiable appetites — sometimes unpleasant byproducts result from all that eating. One example he gives is hydrogen sulfide, or sour gas.

“Bugs need to breathe, and they need to eat. If a bug is eating hydrogen and breathing sulfate, it will produce hydrogen sulfide as its toxic, nasty, corrosive, problematic byproduct,” he explains.

“If hydrogen is being stored and there's sort of any whiff of sulfate available, you could not only be losing your hydrogen, but you could also be creating a corrosive and deadly gas.”

Hubert and team will apply what they’ve learned from years of working with the oil and gas industry to help inform Alberta’s path toward a hydrogen economy.

“We know that bugs are a nuisance in other contexts, and a bunch of strategies have been devised to kill them and control them,” says Hubert.

“Maybe the hydrogen sector needs to borrow some of those strategies from the traditional oil and gas sector. We can repurpose our knowledge for a greener future.”

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