TransCanada acknowledges oil sands crude could sink if spilled

In comments released yesterday by the State Department, TransCanada Corp. acknowledged a possibility that opponents of Keystone XL have long used against the project: The heavy oil sands crude that would run through the controversial pipeline, if spilled in water, could sink below the surface.

The TransCanada acknowledgment, tucked inside a 51-page list of proposed changes to State's March draft environmental review of KXL, came with caveats amid a suggestion that the government alter its reference to sunken crude as "a continual source of oil" if spilled in a river or stream. But the company's conclusion diverges from the avowal, made earlier this year by an environmental scientist representing a competing pipeline giant, Enbridge Inc., that oil sands crude would not sink in water.

"If oil does remain on the water surface for a sufficient time, without being cleaned up, there is the potential for some oil to sink," TransCanada wrote to State in its comments on the department's thousand-page analysis of the $5.3 billion KXL.

At issue is the behavior of the heavy fuel that would make up the bulk of KXL's cargo, a blend of bitumen from the Alberta oil sands with a lighter-weight condensate designed to help the viscous product flow through a pipeline. Environmentalists and other anti-KXL activists point to responders' difficulty in cleaning up the 819,000 gallons of heavy crude that leaked from an Enbridge pipeline in Michigan three years ago as a sign that spilled oil sands fuel is more prone to falling beneath the surface of water than its conventional cousins.

Enbridge has contested the modeling behind U.S. EPA's cleanup orders following that Kalamazoo River spill and, more recently, sought an extension for its restoration deadlines in the area (EnergyWire, March 15). During Canadian hearings on its proposed Northern Gateway pipeline connecting Alberta with the British Columbia coast, the company also challenged critics who described the sinking of spilled oil sands crude as likely.


"It is an immutable fact of physics that they will float," environmental scientist Alan Maki, who previously counseled Exxon Mobil Corp. in Alaska following its 1989 Valdez spill, said of oil sands crude products during February testimony before Canada's National Energy Board (NEB).

An Enbridge spokesman later walked back that statement somewhat, telling Canada's Globe and Mail that oil sands crude is "not likely to sink" away from shorelines if spilled in water (EnergyWire, March 22).

Elaborating on its view of the potential for spilled oil sands crude to sink, TransCanada told State in its April KXL comments that "there are really two types of sunken oil," a water-crude emulsion and a heavier "tar ball" substance. "The tar ball type would be persistent but would not actively disperse free oil," the company added. "The lightweight crude emulsion is not as persistent and could release free oil."

Former U.S. National Oceanic and Atmospheric Administration research chemist Jeff Short reached a conclusion similar to TransCanada's, that the time that oil sands crude is left to weatherize on the surface of water affects its potential to sink, in testimony to the Canadian NEB on the Northern Gateway project. Water temperature, wind speed and the density of the specific type of oil sands crude being transported can also affect the prospects of partially dissolved product becoming submerged, Short concluded.