A process that generates hydrogen fuel while simultaneously storing carbon dioxide underground in rocks shows promise for addressing both energy and climate challenges, according to researchers exploring the approach.
The method works by injecting carbon dioxide into certain rock formations, where the gas reacts with minerals in the stone. This chemical reaction produces hydrogen gas that can be extracted and used as clean fuel, while the carbon dioxide remains trapped in the rock permanently. The process targets ultramafic rocks, which are mineral-rich formations naturally found in Earth's crust.
Scientists at multiple institutions worldwide are developing variations of this dual-purpose technique. The approach addresses two major problems simultaneously: it provides a source of hydrogen without relying on fossil fuels or energy-intensive electrolysis, and it offers a permanent geological storage solution for carbon dioxide that avoids atmospheric accumulation.
The reactions also generate heat, which some researchers suggest could be harvested for geothermal energy production, creating a third benefit from a single process. This thermal component adds another layer of potential value to the system.
However, significant hurdles remain before commercial deployment. The reactions occur slowly at naturally occurring temperatures and pressures, requiring either enhanced rock permeability or higher temperatures to accelerate hydrogen production rates to economically viable levels. Researchers must also ensure that injected CO2 remains safely sequestered over geological timescales and that the process can be scaled up from laboratory demonstrations to full-scale operations.
Cost-effectiveness remains uncertain. The energy required to inject fluids and manage the operation must not exceed the value of produced hydrogen or offset the climate benefits of carbon storage.
Several pilot projects and laboratory studies are underway to optimize reaction conditions and test the approach's practical viability. Success could transform how societies manage both energy production and carbon emissions, though commercialization likely remains years away.