Canada's No.2 pipeline operator said it has filed the formal project application with the National Energy Board, officially starting the clock on a regulatory review of the proposed 4,600 kilometer (2,860 mile) line, a process expected to last about 18 months.

Energy East is TransCanada's most ambitious project to date. The company, which is also the backer of the controversial Keystone XL project, wants to convert an existing natural-gas pipeline to carry 1.1 million barrels per day of crude as far as eastern Ontario, then add new pipe to Quebec and New Brunswick.

The line is expected to open new export markets for Canadian oil producers whose output is rising even as increasing supplies of shale oil from U.S. deposits cut into demand for the country's oil from Midwest refiners, now Canada primary export market.

"We have seen crude production grow in North America quite substantially," Russ Girling, TransCanada's chief executive, told reporters at a press conference.

"We know that we need more pipeline capacity and both Keystone and Energy East are part of that solution and they need to get done to get that crude to market... Demand for these projects is increasing as production increases in North America."

The Energy East line is expected to displace some of the about 700,000 bpd now imported by eastern Canadian refineries, Girling said. But he estimates as much as half of the crude shipped on the proposed line will be exported to refiners in the U.S. Northeast and Gulf Coast, as well as to Europe and as far as India.

Canada's regulatory process and timing is set by law, with the federal cabinet having the final say on whether the project can proceed. TransCanada has waited more than six years for the Obama administration to make a decision on whether its Keystone XL pipeline can go ahead.

Many of the same environmental groups whose concerns have helped delay the Keystone XL project are also opposing Energy East, warning the project will aid the expansion of production from the carbon-intensive Alberta tar sands and increase the risk of oil spills.

"Since 2008, we’ve been told that Keystone XL is a done deal and would be built no matter what, but we’ve successfully blocked that tar sands pipeline for six years," Luísa Abbott Galvão of Friends of the Earth U.S., said in a statement. "Now we’re hearing the same story about Energy East, but we know that we have the power to block this pipeline too."

The line will run from the Hardisty, Alberta, storage hub to Saint John, New Brunswick.

(Reporting by Scott Haggett and Julie Gordon in Singapore)

By Scott Haggett and Julie Gordon