Stimulated geologic hydrogen got a field test outside Boston, where startup Eden GeoPower placed electrodes in two boreholes and sent high-voltage pulses through deep rock. The company calls the technique electrical reservoir stimulation. Its immediate job is to crack the formation, not to use electricity as a direct water-splitting machine.
That distinction is doing a lot of work. Eden's proposed hydrogen-making step comes afterward: water would move through the newly opened fractures and contact iron-bearing minerals. As iron oxidizes, the water-rock chemistry can release hydrogen, according to IEEE Spectrum's account of the test.
The pitch is appealing because much of today's commercial hydrogen is made with fossil fuels, while renewable-powered electrolysis can be costly. The field test, however, does not establish that Eden can make or recover hydrogen at commercial scale.
How does stimulated geologic hydrogen work?
The scheme turns a rock formation into a proposed chemical reactor. High-voltage discharges heat and fracture rock between boreholes, creating more routes for injected water to reach reactive mineral surfaces. In suitable iron-rich rocks, oxidation of iron is associated with reduction of water to hydrogen gas.
Olivine and other ultramafic or igneous rocks are among the materials researchers are studying. University of Texas at Austin researchers describe iron in olivine changing from Fe+2 to Fe+3 as part of the reaction linked to hydrogen generation. Their work is still controlled laboratory research, testing mineral mixes, catalysts and reaction conditions while measuring small changes in gas output, according to the American Association of Petroleum Geologists.
That makes stimulated production different from two adjacent ideas. Natural geologic hydrogen means hydrogen already accumulated underground. Electrolysis uses electricity to split water in equipment at the surface. Eden's approach uses electrical power to alter the rock, then relies on water-rock reactions for the hydrogen.
What has to work before it can become an energy source?
Researchers have to show more than that the chemistry exists. A practical project would need reactions that run fast enough, produce enough hydrogen at a usable concentration, keep water flowing through the intended zones and collect the gas from underground without erasing the economics.
The U.S. Department of Energy awarded $20 million in March 2024 to 18 teams studying low-cost hydrogen production from the subsurface, MIT News reported. MIT assistant professor Iwnetim Abate's group received $1.3 million to investigate variables including catalysts, temperature, pressure and pH.
Those grants are research funding, not evidence of a proven supply. IEEE Spectrum says commercial-scale engineered geologic-hydrogen production has yet to be demonstrated. A University of Texas researcher characterized economic industrial-scale production as a major challenge requiring considerable capital.
The reaction itself is reported not to yield carbon dioxide or methane as products. That is narrower than a full climate claim: the available evidence does not assess emissions from drilling, power for the electrodes, water handling, materials or gas collection. Eden has demonstrated a way to fracture rock in the field; whether the whole chain can deliver affordable hydrogen remains the actual test.
This story draws on original reporting from IEEE Spectrum.
