The project, first announced in 2005, would have carried 830,000 barrels of crude a day from the oilsands in Alberta to Nebraska and connected with the original Keystone pipeline that runs to Gulf Coast refineries.
"I really don't think that this works out to be a major, significant change to American oil supply right now," said Warren Mabee, director of Queen's University's Institute for Energy and Environmental Policy.
"The flow of oil out of Canada ... is now a much smaller part of any big U.S. energy strategy. They've got the capacity in the States to be able to make up for that. They're not really counting on the additional capacity, the growth that Keystone XL would bring."