A new study by NETL researchers, in collaboration with Pacific Northwest National Laboratory and Lawrence Livermore National Laboratory researchers, demonstrated that existing U.S. underground gas storage (UGS) facilities can viably store hydrogen-methane blends, reducing the need to build new hydrogen infrastructure while meeting a range of the hydrogen demand projected for 2050 and helping to support the transition to a clean hydrogen economy.

The research, which is supported by the Office of Fossil Energy and Carbon Management through the Subsurface Hydrogen Assessment, Storage and Technology Acceleration (SHASTA) project, was recently published in Geophysical Research Letters and found that most (73.2%) UGS facilities can store hydrogen blends up to 20% and still meet their current energy demand.

“Hydrogen is a high-energy-content fuel that can be produced with low or zero greenhouse gas emissions from water and other chemicals,” said NETL’s Angela Goodman who coauthored the paper. “In the U.S, existing UGS facilities are a logical first place to consider subsurface hydrogen storage, because their geology has proven favorable for storing methane.”

The research team characterized the hydrogen storage potential of existing UGS facilities in the U.S. and calculated the viability of blending hydrogen with the methane currently contained in the geologic formations.

Unavoidably, filling some percentage of this existing underground storage space with hydrogen means less methane will be available for energy production. Additionally, while hydrogen has a higher energy content by mass than methane, it is much less dense and therefore takes up more space.

Despite these challenges, Goodman and her colleagues found that creating hydrogen during periods of energy surplus and storing it underground could be a feasible long-duration, low-emission, energy storage option that can balance supply and demand for an entire electric grid.

The demand for natural gas and hydrogen constantly fluctuates because users consume energy at different rates during different times of day or year. During times of low demand, power providers store excess gas. Then, during periods of high demand, the stored gas is used to meet the increased energy needs.

“A key finding of this research is that U.S. UGS facilities can buffer between 23.9% of the high hydrogen demand and 44.6% of the low hydrogen demand projected for 2050, which exceeds the current percentage of natural gas demand buffered by storage,” said NETL’s Greg Lackey, the lead author of the study.

The paper’s authors observe that more research will be required to account for the many variables involved with underground storage specific to hydrogen and hydrogen blends; however, current UGS facilities appear to be viable candidates for hydrogen storage

NETL is a U.S. Department of Energy national laboratory that drives innovation and delivers technological solutions for an environmentally sustainable and prosperous energy future. By leveraging its world-class talent and research facilities, NETL is ensuring affordable, abundant and reliable energy that drives a robust economy and national security, while developing technologies to manage carbon across the full life cycle, enabling environmental sustainability for all Americans.