Hydrogen might be the lightest element on the periodic table, but storing it is no light task. The gas needs either high pressures or low temperatures to contain it efficiently, which presents unique challenges in creating and locating suitable storage facilities. Hydrogen metal hydride systems address this by turning hydrogen into a solid.
Metal hydrides are compounds that form when hydrogen is absorbed by metals. Storing hydrogen in a compact, metal form offers distinct advantages due to its ability to avoid the stringent requirements for large, high-pressure or low-temperature environments. When needed, the hydrogen in the metal hydride can be released by applying heat and subsequently used in applications from fueling vehicles to generating electricity for communities.
The National Renewable Energy Laboratory (NREL) began a multiyear partnership with GKN Hydrogen and SoCalGas in 2023 to validate a first-of-its kind demonstration of a metal hydride system that will use waste heat from nearby auxiliary equipment and systems. After more than a year of designing and preparing the site for construction, the metal hydride system was commissioned at NREL’s Flatirons Campus as part of the Advanced Research on Integrated Energy Systems (ARIES) research platform’s megawatt-scale hydrogen infrastructure.
The project, “High Efficacy Validation of Hydride Mega Tanks at the ARIES Laboratory” (HEVHY METAL), is funded in part by the U.S. Department of Energy’s (DOE's) Hydrogen and Fuel Cell Technologies Office. SoCalGas also provided $400,000 of research, development, and demonstration funding to the project.
“The ARIES platform and infrastructure in Colorado aims to help accelerate the deployment of innovative energy technologies related to renewable energy, storage solutions, and interactive loads,” said Katherine Hurst, NREL’s principal investigator for the project. “By integrating GKN Hydrogen’s technology and collaborating with major utilities like SoCalGas, we are developing solutions to tackle the complexities of modern energy systems.”
ARIES is DOE’s advanced research platform for energy system integration research, validation, and demonstration at a scale that reflects the real challenges faced by industry. ARIES can replicate real-world scenarios of broad clean energy deployment, allowing users to safely demonstrate their best pathways to reaching local and national energy goals.
The ARIES hydrogen capabilities allow projects to demonstrate production, storage, and use of hydrogen in a full grid environment integrated with renewable energy assets like wind and solar. Hydrogen produced by a 1.25-MW proton-exchange membrane electrolysis system will be fed to the metal hydride system, which can absorb and store up to 500 kg of hydrogen as metal hydride. When released back into the system in a controlled manner, the hydrogen will be used in a 1-MW proton-exchange membrane fuel cell generator to produce power.
“The hydrogen industry is still nascent,” GKN Hydrogen’s Alan Lang said, “and, so, tends to gravitate towards more known storage mediums such as liquefied or compressed gaseous hydrogen storage. So even though metal hydrides as a hydrogen storage technology have existed for years, they are relatively new at the commercial industrial scale. This demonstration provides a great opportunity to prove their viability and highlight the unique value proposition they offer in terms of safety, footprint, integration, and efficiency in an integrated megawatt-scale hydrogen power-to-power system."
Tuning the Setup for Commercial Demonstration Use Cases
With the stage set at NREL’s Flatirons Campus, the project team is now listening to their audience by collecting input from stakeholders in telecommunications, utilities, and underserved communities to identify promising applications to design various use-case experiments. The team is especially interested in expanding commercial demonstrations beyond fuel cells to a megawatt-scale microgrid level.
“At the demonstration phase, we look to promote the technology to de-risk it,” SoCalGas’ Joe Leiva said. “NREL is a great avenue to de-risk the technologies. Part of our work scope here is to verify and validate the performance of the units and show that this is one way to use this tech. We also want to look at financials—what does it cost to integrate this, and how does it compare to other forms of storage? We want to show that this is an alternative to natural gas and can work.”
The project team will validate the performance of the system for each case, including the rate of discharging hydrogen, ability to maximize the 500-kg storage capacity, and overall efficiency. The team will also investigate the techno-economics from both supply and demand perspectives by comparing clean hydrogen from the metal hydride system to other storage technologies as well as identify the drivers and benefits of commercial use cases.
Amplifying the Impact of Metal Hydrides
HEVHY METAL does more than turn hydrogen into a solid performer. The project advances the U.S. Department of Energy's Hydrogen Shot by offering a low-cost and safe storage solution for hydrogen, poised to deliver substantial benefits to underserved and remote communities by enabling access to affordable and resilient renewable energy and reducing dependence on imported fossil fuels. Additionally, the technology could also support the development of broadband power infrastructure for rural communities, further ensuring the outcomes of the White House's Justice40 initiative.
“It's important—and exciting—to show the interoperability of these hydrogen technologies and how they can be paired with the electrolyzer and fuel cell technologies and understand its performance as a system,” Hurst said. “This will be the world's largest metal hydride hydrogen storage system integrated to renewable energy, and I look forward to seeing how it can help communities become more resilient.”
