Exelon Is Exploring Nuclear Power Plant Hydrogen Production

A first-of-its-kind project spearheaded by Exelon, the nation's largest nuclear power generator, and Norwegian firm Nel Hydrogen could demonstrate an integrated hydrogen production, storage, and utilization facility at an existing nuclear plant site. If the project comes to fruition, it could shed light on a new and potentially lucrative revenue stream for existing nuclear power plants, and boost their economic competitiveness and relevance within organized power markets.

The $7.2 million project is one of 29 projects the Department of Energy (DOE) on Aug. 15 selected to receive up to $40 million in fiscal year 2019 federal funding to advance the H2@Scale concept, which seeks to enable "reliable" large-scale hydrogen generation, transport, storage, and utilization in the U.S. across multiple sectors. Exelon will now begin award negotiations with the DOE for up to $3.6 million in federal funding, which it will cost-share, for the three-year-long demonstration.

Collaborating with Nel Hydrogen U.S., and several national laboratories-including Idaho National Laboratory, National Renewable Energy Laboratory, and Argonne National Laboratory-as soon as it secures the federal funds, Exelon plans to select a site on which to install a proton exchange membrane (PEM) electrolyzer and an associated hydrogen storage system, along with supporting infrastructure, and a control system. The site will likely be in an organized power market, where nuclear economics have lately been challenged by the proliferation of cheap renewable and natural gas power.

Exelon is partnering with Nel Hydrogen and multiple national laboratories to demonstrate an integrated hydrogen production, storage, and utilization facility at an Exelon nuclear plant site. Courtesy: Exelon

A Power-to-Gas Solution

PEM is a popular electrolyzer technology that is offered commercially by several vendors for industrial uses. Nel Hydrogen, for example, recently added newly developed 1-MW and 2-MW modular skid-based PEM hydrogen generator technology to its substantial hydrogen production portfolio, which it says is widely employed for transport and renewable energy solutions.

Similar to fuel cells, PEM employs anodes and cathodes separated by an electrolyte, but in PEMs, that electrolyte is a thin, solid, ion-conducting membrane, which is used instead of the aqueous solution. As part of the process, water reacts at the anode to form oxygen and positively charged hydrogen ions (protons); protons then selectively move across the PEM to the cathode, where they combine with electrons from the external circuit to form hydrogen gas.

But while PEM has been demonstrated commercially, "it has not been scaled up to this point," as Dr. Uuganbayar Otgonbaatar, corporate strategy manager at Exelon, explained to POWER on Aug. 22.

Exelon has already gained substantial knowledge in operating the technology from a smaller electrolyzer at a fossil plant, and hydrogen produced at that plant is used onsite, mostly for turbine generator cooling purposes, said Otgonbaatar. The target size for the nuclear hydrogen project, which will employ a test electrolyzer from Nel Hydrogen, is 1 MW.

"You can think about the 1 MW as the installed capacity of the unit. Depending on how it's operated, the quantity of hydrogen generated from that unit will be different, and it will be operated in a way to match the demand of the power plant," he said.

Another key aspect of the project will be to demonstrate "dynamic operation" of the electrolyzer, as Dr. Lara Pierpoint, director of Exelon Technology Strategy noted. "In this case, that means we're going to be able to control the electrolyzer remotely and show that ideally it can ramp up and down quickly, and be something that could be an asset in your nuclear plants," she said.

If proven feasible, hydrogen generated onsite using nuclear power could be used in several promising ways, Exelon suggests. Along with onsite self-supply to offset operations and maintenance (O&M) costs, for example, it could be sold for injection into gas pipelines, or to the regional hydrogen market, which currently comprises industrial users.

Plan for Now: Hydrogen Self-Supply

For now, however, owing to the scale of the demonstration, Exelon plans to use all the hydrogen on-site and has no intention of selling it. "The idea is to do as much learning as we possibly can over the three years of the project. And our hope, of course, is that this will continue-that the electrolyzer will stay on-site and continue to supply our nuclear plant with all its hydrogen needs, do so economically, and do it using clean electricity to supply the hydrogen process versus traditional methods of obtaining hydrogen that tend to involve some carbon dioxide," Pierpoint said. "In terms of the next step, I think what we would do is, depending on how things work out with respect to the economics and the ability to dynamically operate the electrolyzer, we would investigate whether it might make sense to build a bigger electrolyzer at different nuclear plants."

Questions that would need to be answered before the company embarks on scaling up its nuclear hydrogen production include determining the right sites, and understanding what regional hydrogen markets look like. "So, where we see that there's growing demand for hydrogen close to one of our nuclear plants, and [depending] on the economics and the growth of the hydrogen market, we might consider doing something that looks like a bigger scale operation," said Pierpoint.

The economics of producing hydrogen will also benefit from more probing, she noted. "The parameters that we're checking surround the ultimate price of the produced hydrogen. I think it will be [about] the cost of the electrolyzer, and obviously, the capital cost of the work that we do in the course of the project. Also, the capacity factor of the hydrogen production. It's a unique case, so [we will want to investigate] to what extent we are operating the electrolyzer versus not, and how that changes the economics."

However, nuclear plant hydrogen self-supply would still be a considerable achievement, Otgonbaatar noted. Hydrogen is mainly used on-site in nuclear plants in two places, he said: "Similar to fossil plants, hydrogen is used to cool the generator as a coolant gas, and second-unique to nuclear plants-is that hydrogen is used to control the chemistry of the coolant water in both pressurized water and boiling water reactors."

When the first-of-its-kind project will actually kick off also depends on a number of factors, including when award negotiations with the DOE conclude, Pierpoint said. Navigating the regulatory landscape may also take time. "We're going to be " evaluating very quickly what exactly is the regulatory landscape that applies. It certainly depends on the particular site chosen; that implies different potential state regulations and other things like that," she said.

The Promise of Innovation

Getting the project kicked off despite these potential hurdles has been the biggest milestone, Pierpoint noted.

The demonstration project evolved from "a program that we had specifically to look at our nuclear reactors and think big about what other sorts of products and services we could provide from nuclear power besides just electricity to the markets," she noted. "So, we've been thinking about this for quite some time, but this was a unique confluence of events, where we had identified hydrogen as being a really interesting opportunity." The DOE's funding announcement gave the company an opportunity to "really dig in and see how things might work," she said.

An MIT-educated nuclear engineer who has spent a substantial portion of her career examining nuclear's role within evolving electricity markets and against a complex policy backdrop, Pierpoint is optimistic about the big gains that innovation could reap. She and Otgonbaatar are part of a technical team within Exelon's corporate strategy group that is constantly seeking opportunities to shape new value for its customers, she noted. "We're heavily engaged in innovation and investing in technology like energy storage, for example," she said.

"I'm so thrilled to be working for an organization that not only talks the talk on innovation, but really walks the walk on it," she said. "So, [it's exciting] that we have the kind of support that we do to do a project like this, and to bring together partners and DOE funding. It's really incredible that we have leadership that's very committed to this kind of work to making sure that we keep moving our business forward."

-Sonal Patel is a POWER senior associate editor (@sonalcpatel, @POWERmagazine)

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