Refurbishment of OPG's four Pickering B CANDU units (5 to 8, about 2,000 MW), adding up to 38 years of operating life. Site construction began on September 21, 2026, when Ontario announced more than CAD 3 billion of contracts: about CAD 1.7 billion for the retube, feeder and boiler replacement of unit 5 (a 50:50 Aecon–Candu Energy joint venture, a three-year contract) and about CAD 1.3 billion for turbine-generator replacement (Aecon and Siemens Energy Canada). The units are removed from service by the end of September 2026, and refurbishment officially begins in January 2027 subject to final regulatory approval from the CNSC. More than 90% of project spending is to remain in Ontario, and the project is expected to contribute CAD 41.6 billion to Canada's GDP. The announced date is approximate (Ontario backed OPG's plan to proceed in 2024; the units were originally to stop generating in 2026).