TransCanada didn't disclose the cost of the individual plants but Canadian Solar (Nasdaq:CSIQ) said they're valued at more than $95 million.
The power-generating operations — one in Brockville and the other in Ottawa — will sell their electricity to the provincial grid under 20-year agreements.
The Brockville 2 plant has a capacity to generate 9.0 megawatts of electricity while the Burritts Rapids plant in Ottawa can generate 7.0 megawatts.
Calgary-based TransCanada is one of Canada's largest utility companies, with a North American system of gas and oil pipelines.
TransCanada also is involved in power generation through part ownership of the Bruce nuclear power plant in Ontario and other holdings.
Canadian Solar Inc. is based in Guelph, Ont., and has delivered solar power modules to customers in more than 70 countries.