OPG’s Stewartville hydro station celebrates 75 years of clean power generation
At a glance
- For 75 years, Stewartville Generating Station has been producing clean power on the Madawaska River.
- The reliable station will soon begin an overhaul of its five generating units starting in 2026.
- When it was built, the hydro plant helped support Ontario’s post-war boom period and revitalized the local economy.
In eastern Ontario, near the town of Arnprior, OPG’s Stewartville Generating Station (GS) is marking its 75th anniversary of producing clean power on the Madawaska River.
The station first went into service between September and October of 1948 as a three-unit, 66-megawatt (MW) plant. Two more units were installed in the spring of 1969, increasing Stewartville’s installed capacity to about 182 MW.
Constructed in parallel with OPG’s Barrett Chute GS, which sits just upriver, Stewartville GS helped power Ontario’s post-war boom period. In the years ahead, the plant will continue to play an important role in supporting the province’s growth and electrification.
To celebrate Stewartville’s anniversary, OPG will be hosting an open house at the station on Sept. 16, 2023. For more information, visit opg.com/eastern.
“Stewartville has been a reliable station throughout its 75 years,” said Garry Dicks, Senior Manager of Maintenance and Production for OPG’s five hydro stations on the Madawaska River. “It has been reliable enough that OPG is now investing to refurbish its units, to get another 50 to 100 years of clean power generation to help meet the increased electrical demand Ontario will soon be facing.”
Stewartville has been a reliable station throughout its 75 years. It has been reliable enough that OPG is now investing to refurbish its units, to get another 50 to 100 years of clean power generation.Garry DicksSenior Manager of Maintenance and Production
Starting in 2026, OPG will launch an overhaul of Stewartville’s five generating units, part of the company’s ongoing effort to refurbish units across its hydro fleet to ensure reliable operation for decades to come. This major project is expected to wrap up by 2031, with one unit being overhauled each year.
In the meantime, other projects will soon be underway to keep Stewartville in shape on its 75th birthday. This includes upgrading its electrical equipment to newer, modern equipment, and replacing a powerhouse crane that has reached its end of life. Once installed, the new crane will assist in executing the station’s upcoming overhauls and future work projects.
The station is operated from OPG’s South East Control Centre in Cornwall and maintained by staff at Stewartville.
Reflecting on the station’s history, Dicks notes that stations like Stewartville and Barrett Chute helped set the standard for reliable hydro builds and will help shape future hydro projects in Ontario.
“New hydro builds will likely follow the same model set out by Stewartville, with a powerhouse incorporated into a concrete dam,” said Dicks. “It’s what I would describe as a very typical hydroelectric power station.”
Built over three years by OPG’s predecessor company, Ontario Hydro, Stewartville’s cost of construction at the time was around $10.5 million, or over $140 million today, with a construction workforce that peaked at around 8,000 people.
As part of the development, a camp was established to house hydro workers, with new warehouse buildings and a sawmill also constructed. This flurry of activity transformed the ghost town of Stewartville, a former settlement site dating back to the early 1800s, revitalizing the local community and providing jobs for a large part of the local population.
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