Jan 4 (Reuters) - Enbridge Inc said it will expand its oil pipeline system in Canada between Alberta and the United States border at a cost of about C$400 million (about $400 million).
Canada is the largest source of crude oil imports to the United States, shipping more than 2 million barrels per day to refineries primarily in the Midwest.
Enbridge's expansion of the Canadian mainline system, which will require regulatory approvals, will add an additional 230,000 barrels per day (bpd) of capacity.
The expanded pipeline system is expected to be in service in 2015.
The company early last month proposed a C$6.2 billion expansion of its oil pipeline system, aimed at moving surging volumes of light crude from Western Canada and the North Dakota Bakken to refineries in the eastern part of the continent and U.S. Midwest.
The company's U.S. affiliate, Enbridge Energy Partners , also said it plans to expand the Lakehead System pipeline between North Dakota and Wisconsin.
The expansion of Lakehead, which will add an additional 230,000 bpd of capacity, is expected to be completed in 2015 at a cost of about $200 million.
The International Energy Agency said last month that output from Alberta's oil sands alone is expected to nearly triple to 4.3 million bpd by 2035.
Shares of Enbridge Inc, which has a market value of about C$34.40 billion, closed at C$43.02 on Thursday on the Toronto Stock Exchange.