Researchers from the University of Toronto and the University of Ottawa studied the Canadian Shield, a vast region of some of the oldest rock formations on the planet. For the first time, they directly measured hydrogen escaping from these billion-year-old rocks, tracked how it builds up over time, and mapped where the gas is concentrated.

The findings, published in the Proceedings of the National Academy of Sciences, could help determine whether naturally occurring, or "white," hydrogen can become a practical and economical energy source. The work also introduces a new strategy for hydrogen exploration that may support efforts to reduce greenhouse gas emissions and expand clean energy options.

Hydrogen Flow Measured in Ontario Mine Boreholes

The researchers gathered data from an active mine near Timmins, Ontario. They found that boreholes drilled into the rock release an average of 0.008 tonnes of hydrogen each year, roughly 8 kilograms, which is about the weight of a typical car battery. According to the study, the gas can continue flowing for at least a decade.

When expanded across the site's nearly 15,000 boreholes, the estimated hydrogen output exceeds 140 tonnes annually. The team calculated that this amount could generate approximately 4.7 million kilowatts of energy per year from just one location, enough to meet the yearly energy demands of more than 400 homes.

"The data from this study suggests there are critical untapped opportunities to access a domestic source of cost-effective energy produced from the rocks beneath our feet," says University Professor Barbara Sherwood Lollar in the Department of Earth Sciences in the Faculty of Arts & Science at University of Toronto, the lead author of the study. "What's more, this provides a 'made in Canada' resource that might be able to support local and regional industry hubs and reduce their dependence on importing hydrocarbon-based fuels."

Why Natural Hydrogen Matters

Hydrogen already plays a major role in the global economy, which is valued at roughly $135 billion. It is widely used in fertilizer manufacturing, which is essential for agriculture and global food production. Hydrogen is also important in methanol production and steelmaking.

Today, most hydrogen is produced through industrial methods that rely on fossil fuels such as petroleum, natural gas, and coal. These processes require large amounts of energy and release carbon monoxide and CO2. Even "green hydrogen," which is generated using renewable energy, remains expensive and energy intensive while also requiring transportation and storage infrastructure.

Natural hydrogen, however, has received far less attention. Until recently, most research focused on its role in underground microbial ecosystems and its potential importance for astrobiology and space exploration. Estimates of its energy potential were largely theoretical because scientists lacked direct long-term measurements from real-world sites.

The new study changes that by documenting sustained hydrogen releases over many years.

Ancient Rocks Naturally Produce Hydrogen

"Natural hydrogen is produced over time through underground chemical reactions between rocks and the groundwaters in those rocks," says Sherwood Lollar. "Canada is blessed that vast amounts of its territories, especially on the Canadian Shield, contain the right rocks and minerals to create this natural hydrogen."

The researchers say Canada may have a unique opportunity to produce cleaner and potentially cheaper hydrogen without depending on hydrocarbons. They also note that similar hydrogen-producing rocks exist in many other countries, suggesting the approach could eventually be used worldwide.

The largest concentrations of natural hydrogen appear in geological regions already associated with Canadian mining activity. These include Northern Ontario, Quebec, Nunavut, and the Northwest Territories.

"The common link is the rock," says study co-author Oliver Warr, an assistant professor in the Department of Earth and Environmental Sciences at University of Ottawa. "Natural hydrogen is produced in the same rocks where Canada's nickel, copper and diamond deposits are found, and that are currently under exploration for critical minerals such as lithium, helium, chromium and cobalt. The co-location of mining resources and hydrogen production and use mitigates the need for long transportation routes to market, for hydrogen storage and major hydrogen infrastructure development."

Potential Benefits for Mining and Northern Communities

The study's authors believe natural hydrogen could help reduce both costs and carbon emissions for Canada's mining sector. Hydrogen generated close to mining operations could provide a local energy source without requiring major new transportation systems.

The researchers also suggest that northern communities, which often face high fuel transportation costs, could benefit from nearby hydrogen resources. Using locally sourced hydrogen may lower energy expenses while reducing reliance on imported fuels.

"There is a global race to increase hydrogen availability in order to decarbonize and reduce the costs of the existing hydrogen economy," says Sherwood Lollar. "We now have a better understanding of the economic viability of this resource that can be mapped to hydrogen deposits around the world that are both already known and yet to be discovered."