Ontario has completed the Darlington nuclear refurbishment project ahead of schedule and under budget, marking a major milestone for clean energy production in Durham Region and across the province.
Ontario’s Minister of Energy and Mines, Stephen Lecce, announced that refurbishment work on Darlington Nuclear Generating Station’s Unit 4 is now complete — four months earlier than planned and $150 million under budget. The reactor has received approval from the Canadian Nuclear Safety Commission to begin initial power testing on February 12, with full power expected shortly after.
With all four reactor units refurbished, Darlington is now positioned to deliver more than 3,500 megawatts of clean, emission-free electricity, enough to power approximately 3.5 million homes for at least the next 30 years.
The decade-long refurbishment project is the largest completed nuclear refurbishment in the world and is expected to generate up to $90 billion in economic benefits while supporting approximately 14,200 jobs over the station’s extended operating life.
The work involved thousands of Ontario-based skilled trades and professionals and included replacing fuel channels, feeder tubes, calandria components, and upgrading plant systems to meet modern safety and regulatory standards. During construction, the project contributed an estimated $14.9 billion to Ontario’s GDP, with 96 per cent of spending remaining within the province.
Ontario Power Generation President and CEO Nicolle Butcher said the project demonstrates Ontario’s ability to deliver large-scale nuclear projects efficiently and will help inform future work, including refurbishment at the Pickering Nuclear Generating Station and construction of the G7’s first small modular reactor (SMR) at the Darlington site.
Local leaders praised the project’s impact on Durham Region, with Clarington Mayor Adrian Foster calling the early completion a rare achievement in the global nuclear sector and Regional Chair John Henry highlighting Darlington’s role in securing Durham’s position as Canada’s clean energy capital.
Nuclear power currently supplies about 50 per cent of Ontario’s electricity, and provincial forecasts show demand continuing to rise through 2050 as population growth, electrification, and advanced manufacturing expand.
With Darlington fully refurbished and back online, Ontario officials say the province is well positioned to deliver reliable, affordable, and low-carbon electricity for decades to come.
