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Can Hydrogen Help the Energy Transition? Panel Explores the Benefits and Challenges of Developing More Clean Hydrogen for Fuel

Feature Story| August 23, 2024

By Sara Frueh

One potential resource in efforts to combat climate change is all around us, existing as a part of water, plants, and even fossil fuels like natural gas. Hydrogen is the universe's most plentiful element, the one that fuels our sun and most other stars.

Hydrogen is emerging as a climate solution because burning it doesn't release carbon dioxide. It has the potential to be a replacement for some fossil fuels used in hard-to-abate industries, including in the transportation sector. For example, hydrogen fuel cells have the potential to reduce fossil fuel use in aviation, and their use in heavy-duty trucks could lessen the need for diesel vehicles, cutting down on greenhouse gases and other air pollutants.

But whether hydrogen is truly a climate-friendly alternative depends on its source and whether it is produced in a low-carbon way. And making its benefits possible on a large scale will require adding significantly to the 10 million tons of hydrogen that the U.S. produces annually now - and producing far more of it using renewable energy, explained Ellen B. Stechel, executive director of the Center for an Arizona Carbon-Neutral Economy and professor of practice at Arizona State University.

"The U.S. in its [National Clean] Hydrogen Strategy and Roadmap, which was released roughly a year ago, projects a need for 50 million metric tons per year of clean hydrogen by 2050 in the U.S. - so five times what we have now, and making it all clean," Stechel said.

Stechel spoke at a recent webinar that explored how the U.S. could scale up hydrogen production in a clean way, and the challenges involved in doing so. She was joined by National Academy of Engineering member Yushan Yan, the Henry Belin du Pont Chair in Chemical and Biomolecular Engineering at the University of Delaware and founding director of the university's Center for Clean Hydrogen. Each speaker has over two decades of experience in hydrogen R&D in academic and industry settings.

Hosted by Amanda Staudt, director of the National Academies' Climate Crossroads program, the event was part of the Academies' Climate Conversations webinar series.

"Hydrogen is a colorless, odorless, and flammable gas - which is a necessary characteristic, of course, for it to be an effective fuel," explained Stechel. "It's primarily found in compounds like water, or hydrocarbons such as fossil fuels and biomass, rather than in its free form." Extracting hydrogen from these compounds requires processing to break those bonds, and there are multiple pathways to doing this.

Depending on the source of the hydrogen and the type of energy used to extract it, hydrogen is referred to by different colors - gray, blue, green, and white, among others. Hydrogen that comes from natural gas is referred to as gray hydrogen, which accounts for about 95 percent of hydrogen currently produced in the U.S. and globally, said Stechel. The production process - known as steam methane reforming - emits a significant amount of carbon dioxide to the atmosphere.

If the carbon dioxide emissions produced during that process are captured and stored, rather than released to the atmosphere, then the hydrogen is known as blue hydrogen. "Blue has a lower carbon intensity than gray, but it's not completely carbon neutral, because we can't capture 100 percent," said Stechel.

Green hydrogen comes from non-fossil-fuel sources and is produced using only renewable energy, she explained. One source is water, and the hydrogen is commonly produced using electrolysis, a process that splits water into hydrogen and oxygen molecules using electricity. If the electricity to power the electrolysis comes from a renewable source like wind, solar, or hydropower, the hydrogen is considered green because it generates no direct carbon emissions during production.

"The key advantage of electrolysis is that it can produce hydrogen without any direct emissions, if the electricity used is renewable or nuclear," said Stechel. "That fact alone makes it a cornerstone technology for the transition to a sustainable, low-carbon energy system, with hydrogen playing a really important role."

While there are many challenges to wider development and use of green hydrogen, the greatest challenge is cost, said Yan.

That cost is affected by three factors, one of which is the cost of the electricity used to produce the hydrogen. "We still need to get renewable electricity [to be] cheaper," Yan stated. The second factor is the cost of materials; the electrolyzer stacks used in electrolysis need to get less expensive, which Yan noted is the main focus of his own research. The third factor and challenge is to figure out how to manufacture the electrolyzer stacks and systems on a massive scale at very high speed. "These are the things that are very critical for us to reduce the cost of hydrogen," he said.

Staudt noted public concerns about hydrogen's safety, given its flammability. For many people, hydrogen brings to mind the 1937 Hindenburg disaster.

Hydrogen does have a wider flammability range than other fuels - in air, it can burn at concentrations from 4 percent to 75 percent - and it ignites more easily, said Stechel. But in some other respects, it can be safer, she said; for example, hydrogen is lighter than air, so if there is a leak of hydrogen outside, it will rise and disperse quickly, lowering the probability of ignition. Whereas propane gas is heavier than air and sinks, and liquids like gasoline or diesel pool, making them more likely to ignite.

"Safety needs to be paid very strict attention to, and it has," said Stechel, adding that there are many regulations and safety protocols for managing hydrogen. Yan pointed out that hydrogen has been used for a long time; the world currently uses about 70 million tons per year. "So we know how to handle hydrogen, we know how to transport it, we know how to store it," he said. "Having said that, yes, we still need to be very careful about handling hydrogen."

The speakers also discussed possibilities for overcoming the hurdles that remain to wider use of clean hydrogen.

One important way to decrease the cost of hydrogen is to increase the scale of production - just like solar energy has done in the last 20 years, said Yan. How do you increase the scale? At the beginning, the technology needs some help, he said. "We need to have stable, very well-defined policies from the government - equally federal and state governments - for the hydrogen companies to move forward."

Some policy support is already in place, the speakers explained. In the Infrastructure Investment and Jobs Act, said Stechel, there is $8 billion set aside for the development of regional clean hydrogen hubs, which are networks of hydrogen producers and users meant to accelerate the fuel's use. "It builds a lot of momentum, and it pulls together these ecosystems," she said.

In addition, the Inflation Reduction Act introduces a production tax credit, which can provide up to $3 per kilogram of hydrogen produced, depending on the life-cycle carbon emissions - the lower the carbon intensity, the greater the tax credit, said Stechel. The full credit amount is contingent on meeting specific labor requirements, including prevailing wage and apprenticeship standards.

"These incentives are ... designed to stimulate the development of clean hydrogen facilities and make clean hydrogen more cost-competitive with what the market needs for adoption," she said.