This story is part of a selection of our top news from 2025 that we’re republishing during the holiday break. We’ll be back to our regular schedule in the new year.

Previously posted: May 12, 2025

Critics took a hard line on Ontario’s announcement that it will build four 300-megawatt small modular nuclear reactors (SMRs) at the existing Darlington nuclear plant near Bowmanville, with most concerns focused on the cost of the project and the geopolitical risk in sourcing enriched uranium from a U.S. supplier.

Ontario Power Generation announced provincial approval for the first of the four units May 8, describing it as “the first new nuclear build in Ontario in more than three decades.”

“This is truly a historic moment,” said OPG President and CEO Nicolle Butcher. “This made-in-Ontario project will support provincial companies, create jobs for Ontarians, and spur growth for our economy.”

Energy and Mines Minister Stephen Lecce declared the 1,200-megawatt installation, the first of its kind in the G7, a “nation-building project being built right here in Ontario.” Durham MPP Todd McCarthy called it “the next step to strengthening Ontario and Canada’s energy security.”

The published cost of the project is $7.7 billion for the first reactor, including $1.6 billion for infrastructure and administrative buildings, and $20.9 billion to complete the series of four. Citing Conference Board of Canada figures, OPG said the four SMRs will contribute $38.5 billion to Canada’s GDP over 65 years and sustain an average of about 3,700 jobs per year, including 18,000 per year during construction.

First Mover Advantage or Boutique Pricing?

In the OPG announcement, Butcher suggested an advantage in being the first G7 jurisdiction to bring an SMR to market. “As a first mover on SMRs, Ontario will also be able to market our capabilities and nuclear expertise to the world to further grow our domestic industry,” she said.

The Globe and Mail says the Darlington New Nuclear Project “is being watched closely by utilities around the world,,”, and OPG’s BWRX-300 design “is a candidate for construction in the United States, Britain, Poland, Estonia, and elsewhere.” But “the costs published Thursday are higher than what independent observers argue are necessary to attract many more orders. For comparison, a recently completed 377-megawatt natural gas-fired power station in Saskatchewan cost $825-million.”

Ed Lyman, director of nuclear power safety at the Cambridge, MA-based Union of Concerned Scientists, called the Ontario estimate “an eye-popping figure, but not unexpected given what we know about the poor economics of small nuclear reactors.” That would make the Darlington SMR facility “a boutique unit that’s going to produce electricity for a very expensive price.”

An independent study released last week by the Ontario Clean Air Alliance found that the Darlington SMRs will cost up to eight times as much as onshore wind, almost six times as much as utility-scale solar, and 2.7 times as much offshore wind in the Great Lakes after factoring in the federal tax credit. The analysis by Hinesburg, Vermont-based Energy Futures Group “used data from Ontario’s Independent Electricity System Operator (IESO) but used realistic real-world capital costs and performance measures to develop a more accurate comparison of the cost of nuclear and renewable power options,” OCAA writes.

The report calculates the levelized cost of electricity (LCOE) from different sources in 2030 and 2040, with and without the federal government’s 30% clean energy investment tax credit (ITC). It places the unsubsidized costs per megawatt-hour in 2030 at:

• $33 to $51 for onshore wind;

• $54 for utility-scale solar;

• $105 to $113 for offshore wind;

• $214 to $319 for different SMR designs;

• $279 to $307 for conventional nuclear plants.

By 2040, the prices range from $30 for onshore wind and $41 for utility-scale solar to up to $269 for SMRs and $307 for conventional nuclear. SMR pricing falls as low as $137 per MWh with a 30% ITC.

“It remains unclear how this, and the province’s larger nuclear expansion program, will actually be paid for,” Mark Winfield, co-chair of York University’s Sustainable Energy Initiative, told The Energy Mix in an email. “Putting this on the rate base means higher rates for Ontario electricity consumers, even if the costs are as claimed.”

He added that “the potential role of the federal ITC and [Canada] Infrastructure Bank Investment raises serious questions about what should be defined as ‘clean’ energy given the risks involved in this case, in terms of economic and technological viability, safety risks, and unanswered questions regarding waste streams.”

Critics were already questioning whether field experience with four individual SMRs will be enough to drive down production costs from $6.1 billion plus surrounding infrastructure for the first unit to a range of $4.1 to $4.9 billion for the next three, after the estimated price of the project has already ballooned. Now, with New Brunswick scaling back its SMR development plans, “Ontario is taking something of a technological and economic flyer on this, on behalf of everyone else, underwritten by the electricity ratepayers and, ultimately, taxpayers of Ontario,” Winfield wrote. “This is a project that demands serious economic, technological, and environmental scrutiny, and has been subject to virtually none.”

Uranium Sourced from the United States

OPG is also running into concerns with its plan to power the BWRX-300 with enriched uranium supplied by a firm in the U.S. state of New Mexico. When Donald Trump launched his tariff war earlier this year and began muttering about making Canada a 51st state, Premier Doug Ford applied a short-lived tariff to Ontario power sales and referred publicly to cutting exports as a retaliatory measure. Now, the province is proposing to make 1,200 MW of electricity supply dependent on a vendor that could see its price driven up by tariffs, or be compelled to cut off the supply entirely.

“Developing a dependence on another country for our nuclear fuel has always been a concern, and recent events have proven those concerns are justified,” Bob Walker, national director of the Canadian Nuclear Workers’ Council, told the Globe and Mail in February. “The arrangements are probably as robust as they could be under normal circumstances, but the circumstances are no longer normal.”

In an email to the Globe at the time, OPG spokesperson Neal Kelly described the situation as “very fluid”, adding that “we are proactively evaluating potential impacts and will act as the situation arises.”

Kelly did not respond to an email Monday morning asking whether OPG has any concerns about sourcing enriched uranium from the U.S., and whether it has or needs a Plan B.