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OPG’s Otto Holden GS marks 70 years of producing reliable, clean power

In eastern Ontario, one of OPG’s hydroelectric workhorses is celebrating its 70th year of generating clean power for the province.

OPG's Otto Holden Generating Station is marking 70 years of clean, reliable power.
OPG's Otto Holden Generating Station is marking 70 years of clean, reliable power.

For decades on end, the 243-megawatt Otto Holden Generating Station (GS) has been safely and reliably harnessing power from the Ottawa River, one of four OPG hydro stations operating on the waterway.

“Otto Holden GS is an important part of OPG’s clean hydroelectric fleet, which is instrumental in delivering the low-cost, low-emission power needed to fight climate change,” said Paul Seguin, Senior Vice President of Renewable Generation at OPG. “The station is now currently undergoing a mid-life refurbishment to ensure it can continue its proud legacy of delivering clean power for many more decades to come.”

Back in 1952, when it first went into service, the run-of-river station was one of several new hydro plants put into operation by OPG’s predecessor, Ontario Hydro, to meet the growing power demands of southern Ontario.

It was the third station in two years placed into operation on the Ottawa River, after Des Joachims GS and Chenaux GS, and the 13th new generating station in Ontario Hydro’s rapid post-war expansion program.

Building the sprawling eight-unit facility required clearing 3,100 acres of land and relocating more than 50 kilometres of Canadian Pacific Railway line. In all, more than 2.7 million tonnes of earth and rock were excavated for Otto Holden’s construction, with the station taking shape through the pouring of 300,000 cubic metres of concrete.

Otto Holden Generating Station is named after Dr. Otto Holden, one of the early leaders of OPG's predecessor company, Ontario Hydro.
Otto Holden Generating Station is named after Dr. Otto Holden, one of the early leaders of OPG's predecessor company, Ontario Hydro.

As was the practice at the time, a small colony of 23 houses was built in the nearby town of Mattawa for operating staff, and a 4.8-km highway was built to connect the colony to the station.

Originally called La Cave GS, the plant was renamed to honour Dr. Otto Holden, an accomplished engineer with Ontario Hydro who was instrumental in the expansion of hydroelectric power in the province.

Today, the station is undergoing refurbishment as part of OPG’s $2.5-billion turbine/generator overhaul program.

Work began in June 2021 to overhaul the plant’s Unit 7, which is expected to be back in service sometime in spring 2022. By 2029, all eight of the station’s units will have been refurbished and, in the case of Units 1 to 4, upgraded to improve efficiency.

In addition to the unit overhauls, the project team at Otto Holden will be upgrading the original headgate controls from 1952 to modern standards.

This important work will help ensure Otto Holden GS can continue to operate reliably and efficiently to help Ontario achieve a net-zero carbon future, as outlined in OPG’s Climate Change Plan.