Ontario Bets $26.8 Billion on Pickering Nuclear Refurbishment

The Darlington refurbishment was supposed to be the big one. At $12.8 billion, it was the most expensive nuclear project Canada had ever attempted. Pickering just doubled it. The province has approved $26.8 billion to rebuild four reactors at Pickering Generating Station, the largest nuclear investment in Canadian history.

Pickering’s Units 5 through 8 generate about 2,100 megawatts of electricity. Enough to power roughly 2 million homes. They’re expected to shut down in the third quarter of 2026. Then OPG starts tearing them apart.

Getting Past the CNSC

Nothing moves without the Canadian Nuclear Safety Commission. The CNSC extended Pickering’s operating licence through December 31, 2026, but OPG still needs to file a detailed safety case for the refurbishment: radioactive waste management, worker dose limits, environmental protection during years of construction. Public hearings. Indigenous consultation. An environmental assessment. All before a single bolt gets turned. Environmental groups and the City of Pickering have the right to intervene, and any delays push back construction and extend the period Ontario runs without Pickering’s output.

OPG says it expects regulatory approval by mid-2026. The CNSC has never rushed proceedings to accommodate a project schedule, and it is not about to start. That is not a criticism; it is the point of having a nuclear regulator.

One Reactor at a Time

Unit 5 goes first. Each reactor will be offline for roughly three to four years while workers remove and replace 480 pressure tubes and calandria tubes per unit, along with end fittings, feeder pipes, and steam generators. Much of this happens in a highly radioactive environment, using specialized tooling and robotic systems developed specifically for CANDU reactor refurbishment. That’s 480 pressure tubes. Per unit. In a room you wouldn’t want to spend five minutes in.

OPG’s current schedule targets the first refurbished unit back by 2030 or 2031, with all four online by the mid-2030s. A decade of reduced Pickering output, and at peak construction, 11,000 workers crammed onto one site.

Why Refurbish

Half of Ontario’s electricity comes from nuclear. Half. Demand is projected to grow by as much as 75% in the coming decades: population growth, electrification of transportation, data centres, industrial expansion. All pulling the same direction. None of it optional.

Without Pickering’s output, Ontario would need to replace 2,100 megawatts from somewhere. Natural gas, imported power, accelerated renewable construction. Pick your poison.

The Independent Electricity System Operator has modelled the supply gap. It’s not pretty. During the refurbishment years, Ontario will lean more heavily on gas-fired generation and imports from Quebec and Manitoba, and the IESO’s 2025 Annual Planning Outlook flags possible capacity shortfalls during peak summer demand in the late 2020s, especially if the refurbishment schedule slips or data centre demand materializes faster than expected (a real possibility, given every tech company in North America is hunting for power).

The refurbished units would operate for another 30-plus years, pushing Pickering’s life into the 2060s. A bridge to whatever energy mix the province settles on by mid-century (assuming anyone alive today is still around to see it).

Darlington’s Lessons, Good and Bad

Ontario just went through this at Darlington. The refurbishment began in 2016, originally budgeted at $12.8 billion for four units. Unit 2, the first reactor tackled, ran into trouble early when fuel channel removal took longer than planned. Eighteen months behind schedule.

OPG applied those lessons to Units 3, 1, and 4, which progressed more efficiently; the overall project is now expected to finish close to its original budget.

But the early overruns reinforced a pattern familiar in nuclear construction worldwide: the first unit is almost always the hardest, and schedules set before construction begins tend to be optimistic. Not a controversial observation.

Pickering costs more per unit than Darlington did. OPG blames the age and design differences of the Pickering B reactors, higher labour costs, and inflation. The counterargument is obvious: shouldn’t the second refurbishment be cheaper, given everything learned at the first? OPG says no. The containment designs are different enough that the experience doesn’t transfer as cleanly as outsiders assume. Maybe. Nuclear operators always have a reason the next project is special.

Putting $26.8 Billion in Perspective

$26.8 billion would cover Ontario’s entire annual education budget. Twice.

Nuclear refurbishment has always been eye-wateringly expensive, because the work happens inside a radioactive environment where every step has to be right. Bruce Power’s ongoing refurbishment of eight reactors at its Tiverton facility provides a recent benchmark: Bruce Unit 3 recently completed its construction phase on budget and ahead of schedule (a data point the industry will not stop citing). The Ford government is also supporting Bruce Power’s proposal to build four new large reactors (Bruce C), which could add 4,800 megawatts. First large-scale nuclear build in Canada in more than 30 years. That’s a lot of concrete.

What Ratepayers Will Feel

29%. That is how much Ontario’s electricity rates jumped in November 2025, partly because of rising nuclear generation costs. OPG is seeking roughly a doubling of the payments it receives for nuclear electricity. If granted, monthly bills would increase by an average of $3.50 per year for the next five years.

OPG’s rate application to the Ontario Energy Board covers 2026 to 2030 and requests an increase in the regulated nuclear rate from approximately 7.5 cents per kilowatt-hour to roughly 14 cents by the end of the rate period. Nearly double. OPG says the increase reflects capital costs of the Pickering and Darlington refurbishments, higher operating costs, and investments in new generation capacity. The OEB is reviewing the application, with a decision expected by late 2026.

To offset rate increases, the Ontario government raised the Ontario Electricity Rebate from 13.1% to 23.5%, roughly $36 per month in savings for a typical residential customer. But the rebate is funded by taxpayers, which means the cost is shifted, not eliminated. Your hydro bill looks better. Your tax bill picks up the difference.

Small Modular Reactors at Darlington

Alongside the Pickering refurbishment, Ontario is pursuing a parallel nuclear bet: small modular reactors (SMRs). OPG is building a 300-megawatt GE Hitachi BWRX-300 reactor at the Darlington site, which would be the first grid-scale SMR in Canada. Site preparation licence from the CNSC in 2022. Targeting commercial operation by the late 2020s.

SMRs are supposed to be smaller, faster to build, and cheaper per unit than conventional reactors. No commercial SMR has been built in North America yet.

So Ontario is betting on an unproven product while simultaneously managing the largest nuclear refurbishment in Canadian history. Bold or reckless, depending on whom you ask.

If the SMR works, it opens a path to deploying nuclear capacity in remote communities that currently burn diesel. If it doesn’t, ratepayers carry two nuclear cost overruns at once.

All In

Ontario is going all-in on nuclear at a moment when the technology is fashionable again, with tech companies desperate for clean baseload power and governments scrambling to meet climate targets. The $26.8 billion question is whether OPG can actually deliver. Darlington’s first unit ran 18 months late. Pickering is older, more complex, and more expensive per reactor. The margin for error is effectively zero, and the history of nuclear construction says that margin will not hold.

Sources and verification: The $26.8 billion refurbishment approval is from Ontario government and OPG announcements, confirmed by the Globe and Mail and CBC News. The 2,100 MW capacity and 2 million homes figure are from OPG documentation. The CNSC authorization for Pickering Units 5-8 operation until December 31, 2026 is from CNSC’s October 2024 decision. The refurbishment phasing (one unit at a time, 480 pressure tubes per unit, 11,000 peak workers) is from OPG project documentation. The Darlington refurbishment budget of $12.8 billion and Unit 2 delays are from OPG quarterly reports and the Ontario Auditor General. Bruce Unit 3 refurbishment completion is from NucNet reporting, February 2026. The 29% rate increase and OPG rate application are from the Globe and Mail. OPG’s requested nuclear rate increase (from ~7.5 to ~14 cents/kWh) is from the OEB rate application filing. The Ontario Electricity Rebate increase to 23.5% is from the OEB’s November 2025 announcement. The 75% demand growth projection and capacity shortfall modelling are from the Independent Electricity System Operator’s 2025 Annual Planning Outlook. The BWRX-300 SMR project details are from OPG and GE Hitachi announcements, with CNSC site preparation licensing confirmed in CNSC records.

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