More doubts over spill rate

By Tom Eley
10 June 2010

Evidence continues to mount that the rate of the spill advanced by the Obama administration last week—12,000 to 19,000 barrels—vastly underestimates its actual dimensions. These figures actually represented a low-end range offered by scientists working on on the government-sponsored Flow Rate Technical Group (FRTG). High-end estimates have not yet been released.

More doubts have arisen based in part on BP’s own claims over how much it is extracting through its “top hat” containment dome. BP says that it pumped about 20,000 barrels of oil on Tuesday to a tanker on the surface, though a live feed shows an intense geyser of oil still emerging from the ocean floor. Interior secretary Ken Salazar said he believes 28,000 barrels could be captured daily starting next week.

If this is how much can be collected, it is an admission that the spill rate is at least as great—28,000 barrels, or 1,200,000 gallons a day—and probably significantly more. In other words, BP’s own claims means that a minimum of 60,000,000 gallons has been spilled into the Gulf over the past 50 days, about six times the size of the Exxon Valdez, assuming a constant rate of flow since the April 20 explosion.

However, it is likely that BP’s latest effort to put in place the top hat—which required cutting off the broken riser pipe—actually increased the rate of the spill. This is the opinion of Ira Leifer of the University of California, Santa Barbara, who serves on the government-sponsored Flow Rate Technical Group (FRTG). He told the New York Times on Tuesday that the spill was emitting “way more than it did before. I don’t mean by 20 percent. I mean multiple factors.”

Stephen Wereley, a specialist in particle image velocimetry, has indicated he believes the rate of emission from the ruptured Deepwater Horizon well is between 800,000 and 1.8 million gallons a day, or between 37 million and 87 million gallons to date. Wereley and other scientists on the FRTG have indicated they will release a “high end” range of estimates to complement the low-end estimate of 12,000 to 19,000 barrels released last week. The Obama administration had falsely presented the earlier, low-end estimate as the entire range.

On Wednesday BP acknowledged that it does not have the capacity to receive all of the oil it is pumping up from the ocean floor. The oil giant is now planning to burn excess oil on a separate rig with a device called the EverGreen Burner, which produces vapor rather than smoke through the combustion process. Environmentalists were quick to warn that burning hundreds of thousands of gallons of oil could put massive amounts of toxins into the atmosphere.

BP and the Obama administration continue to claim that it is impossible to know the magnitude of the spill. “How much that is, we’d all love to know,” BP representative Ken Wells said on Monday. “It’s really difficult to tell.”

This is a lie. In addition to particle image velocimetry, which the FRTG is using, there are mechanical devices that can measure the rate of flow. BP is fully aware of this. In the early days of the spill it recruited two scientists from the Woods Hole Oceanographic Institution in Massachusetts to oversee the implementation of such a meter. Richard Camilli and Andy Bowen, who have performed many similar measurements, “were poised to fly to the gulf to conduct volume measurements,” the Times reported on May 14. “But they were contacted [just before their departure] and told not to come, at around the time BP decided to lower a large metal container to try to capture the leak. That maneuver failed. They have not been invited again.”

A scientific response to the spill is impossible without an accurate assessment of its size. “Frankly, I don’t want BP’s number” said marine scientist Samantha Joye of the University of Georgia. “I want an independent estimate because I think BP has financial incentives for not saying exactly how much oil is spilling into the gulf.”