Ontario awards C$3 billion in Pickering refurbishment contracts

Ontario has started site construction for the Pickering Nuclear Generating Station refurbishment and awarded about C$3 billion in contracts for major work at the plant east of Toronto. The contracts cover the first unit's reactor-component replacement and turbine-generator upgrades across the station, advancing a life-extension project expected to return up to 2,200 megawatts to Ontario's grid, subject to regulatory approval.

Key facts

• The two contracts total C$3 billion: about C$1.7 billion for Unit 5 retube, feeder and boiler replacement and C$1.3 billion for turbine-generator work.
• The project covers Pickering units 5 through 8, known as Pickering B.
• The refurbishment will replace 1,520 fuel channels and 48 boilers.
• Ontario expects the refurbished station to provide up to 2,200 megawatts; reactor work is scheduled to begin in January 2027, pending Canadian Nuclear Safety Commission approval.

What happened

The Government of Ontario announced the contract awards on September 21, the same day site construction began. The larger reactor-side contract, worth about C$1.7 billion, went to a joint venture of Aecon Group and Candu Energy, an AtkinsRéalis company. The scope begins with Unit 5's retube, feeder and boiler replacement. Equivalent work on units 6, 7 and 8 is expected in later phases, but those subsequent phases should not be conflated with the Unit 5 contract now announced.

A consortium of Aecon and Siemens Energy Canada received the C$1.3 billion turbine-generator contract. Ontario's release says the work includes 14 new steam turbine rotors, generator overhauls and new auxiliary equipment and controls. Aecon says its portion of the two awards is C$1.75 billion, which it will add to its third-quarter 2026 construction backlog. The C$3 billion figure is the combined value of the two contracts, not the total cost of refurbishing Pickering.

That distinction matters. Ontario Power Generation (OPG) puts the overall refurbishment cost at C$26.8 billion in 2024 Canadian dollars, including interest and escalation. OPG's project page says the schedule remains dependent on regulatory approval. The first announced contract is for Unit 5, while the project plan addresses four reactors and a site-wide turbine-generator scope.

Why it matters

The deal turns a multi-year planning effort into construction preparation and gives the industrial partners substantial defined work. It also illustrates how nuclear refurbishment differs from building a new station: crews will replace major components inside existing CANDU units, while maintaining the plant's broader infrastructure and preparing each unit for a later return to service.

For Ontario, the output target is material, but it is not near-term generation. The province says the completed station could supply up to 2,200 MW, enough for about 2.2 million homes by its estimate. OPG's current timeline places commercial availability of the refurbished units in the mid-2030s. Those projections depend on successful execution, commissioning and the regulatory process; the new contract awards do not themselves guarantee a start date or a completed unit.

The province estimates more than 90% of project spending will remain in Ontario and Canada and projects C$41.6 billion in economic contribution to Canada's GDP. Those are government forecasts, not realized results. The contracts do make the supply-chain commitment more concrete: Aecon, Candu Energy, AtkinsRéalis and Siemens Energy now have announced scopes tied to the refurbishment.

Background

Pickering B comprises four CANDU reactors, units 5 to 8, at OPG's Pickering site on Lake Ontario. Ontario's plan requires replacing the fuel channels and boilers, alongside turbine-generator work. The province lists a new 1.5-kilometre deep-water intake among the supporting infrastructure. In its project materials, OPG describes the refurbishment as a life-extension program, not a new reactor build.

The project follows the refurbishment of OPG's Darlington nuclear station, but Pickering has its own schedule and licensing milestones. OPG says units 5 to 8 are to leave service during September 2026, with reactor refurbishment planned to start in January 2027 and units returning in the mid-2030s. The Canadian Nuclear Safety Commission held the first part of a licence-renewal hearing in June and has scheduled the second part for October 6-9, 2026, according to OPG's project timeline.

The work sits within a wider debate about how existing nuclear plants can meet electricity demand. NNN has covered the role of nuclear generation in firm electricity supply and tracks new projects in its 2026 construction overview. Pickering is a different category from those new-build projects: its planned capacity comes from restoring and upgrading existing units rather than adding a new reactor site.

What's next

The immediate test is the licensing and transition from prerequisite site work to reactor work. OPG lists the CNSC's second relicensing hearing for October 6-9, 2026, and says execution is expected to begin in January 2027 if the required approvals are in place. Ontario's September announcement says all four units will be removed from service by the end of September 2026; OPG's project timeline also lists that month for the offline transition.

Beyond the first Unit 5 contract, watch for detail on later retube, feeder and boiler phases for units 6 to 8, and for progress on turbine-generator procurement and installation. The milestone that will show whether the project is moving from announced work to delivery is regulatory clearance followed by the scheduled start of reactor refurbishment. Until then, the C$3 billion award is a major contract package, not evidence that the refurbishment is complete or that its output is already available to the grid.