The Keystone proposal, along with spills such as Enbridge Inc.’s Michigan rupture in July 2010 and a more recent incident on an Exxon Mobil Corp. line in Mayflower, Arkansas, have led environmental groups like the Natural Resources Defense Council to oppose shipping bitumen by pipeline because they say doing so carries greater risk.
A February 2011 report by the New York City-based NRDC said said spills were more likely because bitumen is acidic and moves through pipelines at higher temperatures than other oils, increasing the risk of corrosion. The National Academy of Sciences report contradicts the NRDC’s research.
Anthony Swift, an NRDC lawyer and an author of the report, said questions remain about higher risks from external corrosion at higher temperatures, as suggested in a 1993 study of California pipelines carrying heavy crudes. Bitumen also may inflict more damage on the environment, especially in waterways, from a spill, he said.
“It does answer some questions, there’s no question about that, and I’m not criticizing the work that the National Academy of Sciences did, but I am commenting on the the very limited scope of the study,” Swift said in a telephone interview from Washington.
Oil and gas pipelines today reach temperatures of about 120 degrees Fahrenheit (49 degrees Celsius), “which is about the temperature of the hot water lines in your house,” Barteau said in a press conference today.
The council found the 1993 California study wasn’t “directly applicable” to today’s pipelines, which have modern coatings and protection from corrosion, Barteau said.
The bitumen is diluted with lighter oils to lower its viscosity in the pipeline.
The alleged corrosive properties of bitumen is one argument made by opponents of Keystone. Environmental groups including the San Francisco-based Sierra Club also argue the pipeline will encourage development of the oil sands.