A TransCanada Keystone Pipeline pump station operates outside Steele City, Neb., in this March 2014 file photo. Reuters WASHINGTON— TransCanada Corp.’s chief executive said the cost to build the Keystone XL pipeline, currently estimated at $5.4 billion, is expected to double by the time the U.S. government completes its review of the largest part of the project. Russ Girling, chief executive of the Calgary, Alberta,-based company, in an interview this week said he expects the project’s cost could increase to a “number that gets you into the high single digits to a 10 number.” He was hesitant to say the project’s cost could double. “I was actually trying to avoid saying those words,” Mr. Girling said. “Obviously, the costs have increased significantly.” The pipeline, which would send Canadian oil sands to the Gulf Coast, has faced delays and has become a political flash point in the nation’s debate over […]