Ancient rocks under Canada are leaking hydrogen, and researchers say the flow is big enough to put a new clean energy source on the map.

Scientists from the University of Toronto and the University of Ottawa studied the Canadian Shield, a region with some of the oldest rock formations on Earth. They directly measured hydrogen escaping from billion-year-old rocks, tracked how it builds up over time, and mapped where the gas is concentrated.

The findings were published in the Proceedings of the National Academy of Sciences. The researchers say the work could help show if naturally occurring, or “white,” hydrogen can become a practical and economical energy source.

At an active mine near Timmins, Ontario, the team found boreholes drilled into the rock release an average of 0.008 tonnes of hydrogen each year, about 8 kilograms. According to the study, the gas can keep flowing for at least a decade.

Across the site’s nearly 15,000 boreholes, the estimated hydrogen output exceeds 140 tonnes a year. The researchers calculated that this could generate about 4.7 million kilowatts of energy a year from 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.”

Hydrogen already has a large place in the global economy, valued at about $135 billion. It is widely used in fertilizer manufacturing, methanol production and steelmaking.

Most hydrogen today is produced through industrial methods that rely on fossil fuels including petroleum, natural gas and coal. The source material says those processes require large amounts of energy and release carbon monoxide and CO2. It also says green hydrogen remains expensive and energy intensive, while also requiring transportation and storage infrastructure.

The new study focuses on natural hydrogen, which has received far less attention. The researchers say earlier estimates of its energy potential were mostly theoretical because scientists did not have direct long-term measurements from real sites.

“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 an opportunity to produce cleaner and potentially cheaper hydrogen without relying on hydrocarbons. They also say similar hydrogen-producing rocks exist in many other countries.

The largest concentrations of natural hydrogen appear in geological regions already linked to Canadian mining activity, including 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.”

The authors say natural hydrogen could lower costs and carbon emissions for Canada’s mining sector. They also say northern communities, which often face high fuel transportation costs, could benefit from nearby hydrogen resources.

“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.”

Read more from Science Daily.