Construction on the first of four small modular reactors at a nuclear station east of Toronto is set to begin this year with the entire project costing $21 billion.
The first reactor at the site of the Darlington Nuclear Generating Station should be completed by 2030, officials said.
The Canadian Nuclear Safety Commission approved Ontario Power Generation's plan last month to build the first of four reactors.
"We're breaking ground on a project that when complete will produce power for 1.2 million homes, 1,200 megawatts of power," said Energy Minister Stephen Lecce.
The project will create 18,000 jobs, including 3,700 highly skilled jobs.
Lecce said 80 per cent of the spending on the entire project will go to Ontario companies that are providing skilled workers to build the new reactors.
"Our workers, our welders, our boilermakers, our heavy equipment operators will build this project with Canadian steel, Canadian concrete, and Canadian innovation," he said.
Once built, the small nuclear reactors will operate for 65 years, the province said.
OPG selected GE Hitachi's small modular reactor technology. The American-Japanese company has its headquarters in the United States.
Green Party Leader Mike Schreiner said it's a real gamble during an ongoing trade war with the United States.
"I think it's irresponsible for the government to be bringing in an SMR with U.S. technology that's going to lock us into needing enriched U.S. uranium to have it work," Schreiner said.
The province's nuclear generator fleet are CANDU reactors that do no need enriched uranium, but the SMR technology does.
The Independent Electricity System Operator said last year that electricity demand is expected to increase 75 per cent by 2050.
The moves are part of a larger push from Lecce to rely more heavily on nuclear generation to power the province's growing electricity demands.
The plan also includes exploring a new, large-scale plant at Bruce Power in Tiverton, Ont., considering a new nuclear plant near Port Hope, Ont., and refurbishing units at the Pickering nuclear plant to extend its lifespan.
Lecce is also bullish on exporting Ontario's nuclear know-how abroad. The province has signed agreements worth more than $1 billion with companies in Estonia, Poland and the Czech Republic.
Those agreements will see Canadian companies and workers build and operate reactors oversees, his office said.
This report by The Canadian Press was first published May 8, 2025.
Allison Jones and Liam Casey, The Canadian Press
