Canada's OPG to receive government support for SMR construction in Darlington

Ontario Power Generation (OPG) will secure new financing for the Darlington New Nuclear Project (DNNP). Two public institutions will invest a total of CAD 3 billion (approximately CZK 45.1 billion) and take minority stakes, with the aim of reducing the risks associated with the construction and future operation of these small modular reactors.

The Canada Growth Fund (CGF) will invest up to CAD 2 billion in return for a 15% stake. The CGF is a CAD 15 billion fund focused on attracting private capital to the clean economy. The Building Ontario Fund (BOF) will invest a further CAD 1 billion for a 7.5% stake. The BOF is a Crown agency with a budget of CAD 8 billion for revenue-generating infrastructure projects in Ontario. OPG will remain the project's majority owner and operator.

Investment model and project scope

On 8 May 2025, the province of Ontario approved the final investment decision, giving OPG the go-ahead to build the first commercial SMR in a G7 country. Four BWRX-300 units (GE Vernova Hitachi Nuclear Energy) will be built at Darlington, with a total installed capacity of up to 1,200 MW. The project's total cost is estimated at CAD 20.9 billion (≈ CZK 313 billion). A licence to build the SMR was issued this spring.

The CGF and BOF will use their mandates to temporarily take on some of the key risks—particularly construction and technology risks—which are currently holding back private-sector interest. The aim is to pave the way for private and regional investors to come on board.

Financing will be provided in two stages. The first will provide initial capital for SMR 1. The second will provide additional funding for SMRs 2–4 once agreed milestones have been reached.

The project is a regulated asset, with revenues overseen by the Ontario Energy Board, which is expected to make it easier for additional private investors to participate.

Schedule for first operation

The DNNP was added last month to the first group of projects being reviewed by the newly established federal Major Projects Office, which is tasked with accelerating the preparation and approval of major investments.

The investment announcement stated that the project would create thousands of skilled jobs and provide clean energy for hundreds of thousands of households in Ontario. The provincial leadership described it as a “down payment” on a nuclear future, with plans for both SMRs and new large nuclear units that are intended to make Ontario an energy powerhouse.

OPG expects construction of SMR 1 to be completed and the unit connected to the grid by the end of 2030. Construction of SMRs 2–4 is expected to be completed in the mid-2030s.

Progress at the Darlington site

Since the government approval in May, OPG has reached several milestones at the construction site (preparatory work has been underway since 2022).

The "Harriet Brooks" tunnel boring machine (named after Canada's first female nuclear physicist) arrived at the site in July. Assembly is planned for early 2026. The machine, which is 6.97 m wide, will bore and line a 3.4 km tunnel for the condenser cooling circuit.

The first sections of the reactor building's foundation slab module (Basemat) have also arrived at the construction site. Once assembled, the completed module will be lowered by crane to the bottom of the reactor shaft, 35 m below ground.

Construction of the pre-assembly and assembly (fabrication) halls has also been completed. Structural sections of the SMR 1 reactor building will be prepared and assembled in the pre-assembly hall, while the final assembly of modular components will take place in the fabrication hall.

In addition, the foundations for the radioactive waste building and service buildings are complete, and groundwork has been carried out for three further SMR units.