Enbridge will buy all outstanding common shares of Tonbridge for C$20m ($20.36m) through a plan of arrangement.
The company will also repay about C$50m ($50.9m) of debt incurred in the development of the Montana-Alberta Tie-Line power transmission project being developed by Tonbridge.
Enbridge said it will be entitled to receive about C$9m ($9.16m) in a combination of cash and warrants if the arrangement is not completed in certain circumstances.
The company will inject further funding to complete the first 300MW phase of the transmission line as well as a low cost expansion to 550-600MW.
The total cost to Enbridge for both phases of the power line project will be about C$300m ($305m), the company said.
The Montana-Alberta Tie-Line project is a 345km power line linking Great Falls, Montana with Lethbridge, Alberta.
