Advancing clean hydrogen production and exploiting hydrogen’s unique properties to decarbonize agriculture and manufacturing
Generating electricity from sources that do not emit greenhouse gases, or that emit low levels of them, is key to the overall mix of solutions for climate change. These sources include wind, solar, and waves.
And while there are many ways to deploy green electricity, several Northwestern researchers see hydrogen production as an important avenue. Hydrogen is clean—the only product from using it is water—and it can be used to store and deliver energy from other sources.
Hydrogen offers several benefits. When produced from renewable or nuclear electricity, it can ultimately help decarbonize high-polluting industries, mitigate climate change, and reduce emissions while creating more jobs — a vision called the “hydrogen economy.”
In addition, it can mitigate local pollutants that come from burning diesel fuel and gasoline.
“Imagine all the truck traffic on I-90,” said Jennifer Dunn, professor of chemical and biological engineering. “It generates particulate matter emissions that affects the health of nearby communities. If you use hydrogen to power those trucks, those communities would have cleaner air.”
As part of the Paula M. Trienens Institute for Sustainability and Energy’s Deploy pillar, Northwestern is leading the development and testing of clean hydrogen production and exploiting hydrogen's unique properties to decarbonize the U.S. economy, from transportation to agriculture and manufacturing. The pillar is one of Trienens Institute's Six Pillars of Decarbonization aimed at leading interdisciplinary research in decarbonization.
“Ultimately, we need green electricity to realize the benefit of sources like hydrogen,” said Dunn, who co-leads the pillar. “But we want to be sure that these hydrogen technologies are ready to use when green electricity is abundant. We want to be part of the national conversation on what it will take to realize the hydrogen economy.”
Barriers to widespread hydrogen use remain. Today, most hydrogen is produced using fossil fuels—by steam reforming either natural gas or coal. Using carbon-free electricity to make hydrogen generally involves electrolysis, a process that splits water into hydrogen and oxygen using carefully designed electrochemical devices. Another approach uses solar concentration to generate high temperatures to split the water. These approaches are still not cost competitive with fossil fuel derived hydrogen. In addition, hydrogen needs much more storage space and infrastructure for shipping and delivery than conventional fuels. Safety concerns must be addressed as hydrogen infrastructure expands.
The U.S. Department of Energy (DOE) has set a target for clean hydrogen of a dollar per kilogram. At that price, the DOE anticipates that hydrogen could be a game-changer as a fuel and energy storage medium.
“The goal is to make the cost of hydrogen so low that there is no excuse not to use it instead of fossil fuels. Ideally, this will free us from having to solve tough policy issues because clean hydrogen is so inexpensive,” said Sossina Haile, Walter P. Murphy Professor of Materials Science and Engineering and co-lead of the Deploy pillar. “It’s an ambitious goal, but it’s possible, and everything we are doing at the Trienens Institute is contributing to that possibility.”
Several initiatives at Northwestern are working toward low-cost, clean hydrogen. Northwestern is a key partner in the Midwest Alliance for Clean Hydrogen (MachH2), one of seven regional clean hydrogen hubs funded by the DOE. MachH2, a public-private entity, is working to promote commercially scalable projects that will stimulate clean hydrogen production and supply hydrogen to end users. The hub plans to produce tens of thousands of metric tons of hydrogen per year.
Dunn serves as the project’s chief decarbonization officer and is focusing on quantifying greenhouse gasses emitted in making and using hydrogen. Hydrogen gas made from natural gas, for example, is cost-effective but emits more greenhouse gasses than other processes. “We have parallel needs: decarbonize the grid and develop technology for using electrochemistry to produce hydrogen,” she said.
Dunn, whose expertise lies in life cycle analysis of emerging technologies, is also working on evaluating tax credit policy for producing hydrogen from green energy sources. “The framing of tax credit eligibility for hydrogen producers in the U.S. is really interesting with stipulations including proving that they used green electricity that is new or otherwise would have gone unused,” she said. Collaborators in that study include Chiara LoPrete of Penn State University.
Northwestern has also received more than $10 million from the DOE to lead an Energy Frontier Research Center (EFRC) focused on the fundamental science underpinning hydrogen-based energy technologies called the Center for Hydrogen in Energy and Information Sciences (HEISs).
That center is led by Haile, a fuel cell pioneer who has developed record-performance fuel cells in both electrolysis (for hydrogen production) and power generation. Her colleague Scott Barnett, professor of materials science and engineering and a Faculty Affiliate of the Trienens Institute, has also achieved record performance on these cells at higher temperatures, and is studying how to make them last longer.
Northwestern researchers are also pursuing methods to make ammonia, which has been proposed as a way to store and transport hydrogen. “Ammonia is much easier to transport, and tends to leak much less than hydrogen," Haile said. A key advance has been the development of electrochemical devices that then convert the ammonia back to hydrogen for use in fuel cells. Ammonia is also the main ingredient of fertilizer, and ammonia production is responsible for about 4% of carbon dioxide emissions today, another reason to target ammonia.
Northwestern’s research in hydrogen is fueled by faculty including Ted Sargent, executive director of the Trienens Institute, and Linsey Seitz, assistant professor of chemical and biological engineering and a Faculty Affiliate of the Trienens Institute. David Dunand, professor of materials science and engineering, is deploying hydrogen to decarbonize manufacturing of steel. Partnering with Argonne National Laboratory allows researchers access to facilities to help them characterize materials and processes. Argonne is a partner in HEISs and is involved in MachH2 research.
Ultimately, researchers from the Deploy pillar will build on the research of those working across the Six Pillars of Decarbonization to reduce fossil fuels. Together, they hope to facilitate a transition to clean energy. “If they can create green electricity, we can be ready to help store it,” Dunn said.