This article was written on Nov. 25, 2025 for Interesting Engineering by Georgina Jedikovska.
The industrial foundations of Cumberland run deep. ACET researchers are determining how these now-abandoned coal mines under the village could generate geothermal energy to heat and cool buildings. (Source: Cumberland Museum and Archive.)
Vancouver Island’s village of Cumberland once anchored the region’s economy, as workers extracted more than 16 million tonnes of bituminous coal from 1888 until the late 1960s. The coal once fueled ships, heated homes, and even supplied smelters in Japan. When the mines closed, they left deep shafts, sprawling tunnels and long-term risks, including methane pockets and unstable voids.
Now, an initiative developed through the University of Victoria’s Accelerating Community Energy Transformation (ACET) program aims to turn the abandoned shafts and tunnels into a community-scale energy system.
A new use underground
The ACET team is studying how groundwater trapped in the abandoned mines maintains stable temperatures year-round. It remains cooler than the surface in summer and warmer in winter.
Zachary Gould, ACET community energy planner and project lead, said that by taking advantage of the temperature difference, heat pumps could use water from abandoned mines to provide heating and cooling for buildings at relatively low cost and with near-zero carbon output.
“[The Cumberland District Energy project] is technically a very large ground-source heat exchanger.” Emily Smejkal, a research fellow with the Victoria-based Cascade Institute who specializes in geothermal energy.
With approximately 4,800 residents, Cumberland is a small municipality with a big community. Image credit: Sara Kempner Photography
Mayor Vickey Brown said the project honors the region’s past while advancing a clean-energy future. “It’s something that old Cumberland can be proud of, because we’re using the waste of that old resource to transition to cleaner energy,” Brown added. These mines, according to the researchers, are ideal for a closed-loop geoexchange system. They are certain that with a network of shafts running beneath the village, the entire community could tap into this clean energy resource.
For now, the first energy models focus on a proposed civic precinct that includes a community centre, municipal offices and potential affordable housing, along with a large industrial area near Comox Lake.
Cumberland’s energy shift
Apart from the technical benefits, the project offers a symbolic reimagining of Cumberland’s industrial past. Coal mining shaped the town for decades, but workers faced dangerous conditions, low pay, and frequent injuries. Meanwhile, the coal they produced contributed to global emissions. Repurposing the old mines will enable the community to reclaim a resource once associated with exploitation and environmental damage.
“It’s about reimagining these old resources and relics of industry,” Cory MacNeill, a Cumberland local and geologist, noted. “It’s really powerful to look at all of this mining and look at ways that we can benefit from it from a more environmental standpoint.”
Geologists have mapped the extensive mine system running beneath Cumberland to better understand its energy potential for the community above. Image credit: ACET
Similar transitions are already underway in Canada. Geothermal systems built on abandoned mines are operating in Nanaimo, British Columbia, and in Springhill, Nova Scotia. These projects helped inspire Cumberland’s approach.
Brown revealed she was already aware of the Nanaimo geothermal project when she learned about ACET’s search for municipal partners. “I thought we could use this project to figure out whether geothermal could work for our buildings, because we want to redevelop the block,” she concluded in a press release.
She believes that providing affordable, energy-efficient heating and cooling to businesses could make Cumberland industrial land more attractive for development, particularly for greenhouses and food processors.