OPG Approved to Begin Construction on First Small Modular Reactor at Darlington Nuclear Site
May 21, 2025
The Ontario government has approved Ontario Power Generation’s (OPG) plan to begin construction on the first of four small modular reactors (SMRs) at the Darlington nuclear site.
Once in service by the end of 2030, the first BWRX-300 SMR unit will be capable of generating 300 megawatts (MW) of safe, low-carbon, reliable, Ontario-made power—enough to power about 300,000 homes. In total, OPG’s SMR fleet will be capable of producing 1,200 MW of electricity to help support Ontario’s electrification, while serving as a growth platform for Canada’s nuclear supply chain.
“This is truly a historic moment. This made-in-Ontario project will support provincial companies, create jobs for Ontarians, and spur growth for our economy. OPG is proud to be leading this first-of-a-kind project. With the province’s robust nuclear supply chain and our successful track record on nuclear projects, particularly our Darlington Refurbishment, we are confident we will be able to deliver the first SMR unit for Ontario, on-time and on-budget.”
Nicolle Butcher, OPG’s President and CEO
The construction of the four units will support the government’s plan to protect Ontario’s workers and economy by creating up to 18,000 Canadian jobs and injecting $500 million on average annually into Ontario’s economy. The construction, operation and maintenance of the four units will add $38.5 billion to Canada’s GDP over the next 65 years.
The government has worked with OPG to ensure that 80 per cent of project spending goes to Ontario companies and that construction and operations will protect Ontario workers and jobs by sustaining an estimated 3,700 highly-skilled, good-paying jobs for the next 65 years.
The BWRX-300 is a small-scale nuclear reactor that uses commercially available uranium to generate power. The four SMRs will be vital to powering new homes, historic investments to build Ontario and fuel a thriving economy. Once complete, they will produce 1,200 megawatts (MW) of electricity, enough to power the equivalent of 1.2 million homes, to help bridge a power gap that could emerge in the early 2030s in the absence of net-new baseload power sources added to the grid.
More than eighty Ontario companies have already signed agreements with OPG to deliver this first-of-a-kind project, establishing themselves as leaders in the growing domestic and global markets for new nuclear technologies. The government has also negotiated additional commitments from GE Hitachi that will create jobs in Ontario, that will soon be unveiled.
“Small modular reactors are a game changing technology necessary to electrifying Canada,” commented Francis Bradley, President and CEO, Electricity Canada. “They can provide stable, affordable baseload power and support the integration of variable renewables. This announcement also signifies the start of an important tipping point: once we’ve built the first SMR, we can build the second, and the third. We can get moving to providing reliable electricity to more Canadians– and continue to power the Canadian economy both now, and in the future.”
Go HERE to read OPG’s story on the project
Quick Facts
- The government is supporting OPG’s $20.9 billion budget for the Darlington New Nuclear Project, which includes site preparation, engineering and design work to date, as well as the construction of all four small modular reactors.
- During project development OPG will continue to build respectful, collaborative relationships with the communities of the Williams Treaties First Nations, while pursuing potential opportunities for their equity partnership in the project. This would be a first-of-its-kind partnership in Canada for nuclear energy generation, reflecting the government and OPG’s commitment to ensure local First Nations benefit from new projects in their territories.
- Once complete, the Darlington New Nuclear Projects four SMRs will produce 1,200 megawatts (MW) of electricity, enough to power 1.2 million homes.
- According to the IESO, the province would need to build up to 8,900 MW of wind and solar paired with battery storage to replace the output of four SMRs. The IESO also concluded this alternative approach would carry significant risks including significant land requirements and the need for large scale transmission build out.
- The first SMR will cost $6.1 billion, along with costs for systems and services common to all four SMRs of $1.6 billion. Costs are expected to decline with each subsequent unit as efficiencies are gained, similar to the Darlington Refurbishment Project.
- OPG began site preparation for the first SMR in December 2022. Ontario announced that OPG would begin planning and licensing for three additional SMRs, for a total of four SMRs at the Darlington nuclear site in July 2023. OPG obtained a Licence to Construct (LTC) for Unit 1 from the Canadian Nuclear Safety Commission (CNSC) in April 2025.
- To reduce costs the Government of Ontario is exploring potential financial instruments that would benefit ratepayers, and in parallel, OPG continues to explore other optimal financing arrangements.
