Ontario Power Generation

Ontario Power Generation (OPG) is a provincial Crown corporation wholly owned by the Government of Ontario, Canada. It was established on April 1, 1999, following the restructuring of Ontario Hydro — the provincial utility that had operated Ontario's electricity system since 1906. When Ontario Hydro was disaggregated, OPG inherited the generation assets, while the transmission network became Hydro One. OPG is headquartered in Toronto (with major operations in Oshawa, Darlington, Pickering, and Niagara Falls) and employs over 9,500 people. Ken Hartwick serves as President and CEO.

OPG is one of the largest and most diverse electricity generators in North America, with a total generating capacity of approximately 16,000 MW spanning nuclear, hydroelectric, thermal, biomass, and solar generation. Its nuclear fleet includes the Darlington Nuclear Generating Station and (historically) the Pickering Nuclear Generating Station, which was in the process of being refurbished or decommissioned as of 2025. OPG's hydroelectric portfolio includes more than 65 stations on Ontario's river systems, producing over 7,000 MW of capacity that represents the majority of Ontario's dispatchable clean power. Together, OPG's nuclear and hydro assets generate approximately half of Ontario's electricity, making it the dominant contributor to Ontario's 95%+ carbon-free electricity grid.

OPG's most significant current project is the Darlington New Nuclear Project — the construction of a GE Hitachi BWRX-300 small modular reactor (SMR) at the existing Darlington site. In December 2022, OPG began site preparation, making it the first SMR to enter construction in the G7. The BWRX-300 is a 300 MW-class boiling water reactor designed for simplified construction and lower capital cost than large reactors. OPG has also announced plans for up to three additional SMRs at Darlington and is collaborating with provincial utilities in New Brunswick (NB Power) and Saskatchewan (SaskPower) to deploy the same technology, positioning Canada as a global leader in SMR commercialization.

OPG also operates the Darlington Energy Complex, a large battery storage facility, and participates in the Ontario electricity market as a major generator operating under regulated agreements with the province's Independent Electricity System Operator (IESO). As a Crown corporation, OPG reinvests earnings into Ontario's electricity infrastructure rather than paying dividends to private shareholders, and its capital plans are guided by Ontario's provincial energy policy.