Researchers are developing a process that simultaneously stores carbon dioxide in rock formations while extracting hydrogen gas, offering a dual climate benefit that multiple teams are actively pursuing.
The approach works by injecting captured CO2 deep underground into certain rock types. Chemical reactions between the CO2 and minerals in the rock produce hydrogen gas that can be extracted and used as a clean fuel. This addresses two critical climate challenges at once: removing greenhouse gases from the atmosphere and generating renewable hydrogen without carbon emissions.
The process also generates heat as a byproduct, which some research groups are exploring for geothermal energy production. This potential third benefit would create an integrated system producing both hydrogen fuel and renewable electricity from a single geological operation.
Several teams are testing this concept at different scales. The appeal lies in the efficiency gains and economic viability. Rather than spending energy solely on carbon storage, operators capture value through hydrogen production. The hydrogen can replace fossil fuels in industry, transportation, and power generation. Simultaneously, the stored CO2 remains trapped in solid mineral form, providing permanent sequestration rather than temporary storage in liquid or gas phases.
The process targets specific rock types rich in minerals like olivine that react readily with CO2. Geological surveys are identifying suitable formations worldwide, particularly in regions with existing infrastructure for CO2 transport and hydrogen distribution.
Challenges remain. The technology requires significant capital investment upfront. Hydrogen extraction rates and efficiency depend on rock composition, temperature, and pressure conditions. Scaling the process from laboratory demonstrations to commercial viability requires solving engineering problems around injection rates, mineral precipitation, and long-term rock stability.
The projects underscore growing recognition that climate solutions may need to serve multiple purposes simultaneously. Single-use carbon capture technology faces economic hurdles. Combining CO2 storage with hydrogen production creates a more compelling financial case while accelerating the transition to clean energy systems.