Under the terms of the deal, Hydro One will purchase various entities that own and control Great Lakes Power Transmission, an Ontario-regulated electricity transmission business operating along the eastern shore of Lake Superior, north and east of Sault Ste. Marie, Ontario.

The transaction is subject to regulatory approval , including receipt of Competition Act (Canada) approval and approval of the Ontario Energy Board.

Additionally, the firm will also assume C$151m in debt.

Upon completion of the deal, Hydro One will operate approximately 98% of transmission capacity in Ontario.

Great Lakes Transmission business involves 15 transmission stations, 560km of high and medium voltage 44-230kV transmission lines, and related infrastructure covering an area of 12,000km2 and connects to Hydro One’s Wawa and Mississagi transmission stations.

Hydro One said that the deal follows its initial public offering (IPO) in November and the recent purchase of three local distribution companies.

Hydro One president and CEO Mayo Schmidt said: "Our intense focus on customers and communities together with our disciplined approach to leveraging strategic opportunities is an important combination as we move forward with the transformation of this company."

Hydro One owns and operates Ontario’s 29,000km high-voltage transmission network which delivers electricity to large industrial customers and municipal utilities, as well as a 122,000km low-voltage distribution system.