Underground hydrogen storage remains a key research topic for NETL

Underground hydrogen storage is a key research area associated with NETL’s overall contribution to the US Department of Energy’s (DOE) Hydrogen Shot.

Renewable energy sources such as wind, hydro, solar, biomass and geothermal represent an increasing share of the total energy supply and contribute to reducing carbon dioxide (CO2) in the air. However, coping with the intermittent supply associated with these energy sources and the variable demand for energy is a major challenge.

Converting energy produced by renewable sources into hydrogen, then storing it for future demand, is seen by energy experts as a response to the challenge and NETL researchers are working independently and as members of a unique multinational laboratory team to make this approach feasible.

Using hydrogen as a fuel source has been identified by the DOE as a critical step toward transitioning to a net-zero carbon society if storage issues can be resolved. Large-scale geological hydrogen storage offers the ability to balance inter-seasonal gaps between supply and demand, decouple power generation from demand, and decarbonize heating, transportation, and other industrial processes difficult to decarbonize.

Natural gas has been stored in depleted oil and gas fields, saline aquifers and salt caverns for decades. However, the impacts of underground hydrogen storage on reservoirs, the risks of hydrogen leakage, and the flow behavior of hydrogen and blended mixtures are not well understood. The new demand for widely available hydrogen sources and the possibilities of using hydrogen blended with natural gas will require storage tanks at various locations in the United States.

“Storing hydrogen underground is less expensive than storing it in tanks above ground,” explained Angela Goodman of NETL’s biogeochemistry and water team. “But the technical challenges have to be overcome. We team up with other national laboratories to focus on quantifying material compatibility and studying potential microbial interactions.

She said the NETL researchers were working with colleagues at Pacific Northwest National Laboratory and Lawrence Livermore National Laboratory under a research umbrella known as the SHASTA —Assessment, Storage, and Acceleration of Underground Hydrogen Technology — to generate knowledge leading to effective and widespread use of underground storage for the country’s hydrogen and the energy it can bring to decarbonization efforts.

SHASTA was organized by the DOE’s Office of Fossil Energy and Carbon Management. SHASTA researchers are determining the viability, safety and reliability of storing pure hydrogen or hydrogen-natural gas mixtures in underground environments.

Goodman told NETL that experts are supporting the SHASTA initiative by addressing a series of challenges, including:

  • Feasibility of hydrogen storage in a variety of underground systems.
  • Behavior of hydrogen gas during storage.
  • Loss of hydrogen by biogeochemical reactions.
  • Risks of loss of containment of storage tanks, by cover rock, faults. fractures or leaky pits.
  • Development of real-time monitoring technologies to ensure storage integrity and security.
  • Levels of support from key stakeholders and the public.
  • Expected regulatory environment.

Hydrogen is currently stored in salt caverns around the world, but these geological formations are not widely available in the United States. SHASTA’s work aims to address this problem by exploring hydrogen storage in saline formations and depleted oil and gas wells that are more geographically disbursed. all over the United States

“Our work builds on existing subsurface capabilities that were designed to study wellbore and subsurface responses,” Goodman said. “The lab’s capabilities will also be used to assess the geochemistry and microbiology of reservoir types targeted for storage and to develop fiber optic sensors needed to monitor underground storage.”

In addition to expert personnel, NETL contributes a collection of technical research tools to the SHASTA effort, including equipment that examines wellbore cement integrity, microbial characterization, sensors, assays, and many other technical aspects of hydrogen storage.

Goodman said the SHASTA initiative “can accelerate and expand the use of hydrogen using existing natural gas facilities at storage sites across the United States, addressing critical technical barriers, demonstrating the feasibility of emerging technology and developing tools and technologies to support industry and enabling the advancement of underground hydrogen storage.

Bonny J. Streater