Wednesday, April 28, 2010

Louisiana Oil Spill to be Burned?

The oil slick as seen by the European Space Agency's Envisat

So far efforts to shut off the leaking oil well in the Gulf of Mexico have been unsuccessful. The next step to control the leak would be to build an underwater dome, a process that could take up to a month. A more permanent solution would be to drill a relief well and block the wellhead that is currently leaking. That process would take several months to complete.

In the meantime, the wellhead is spilling 42,000 gallons of oil per day into the Gulf of Mexico. Officials are considering a controlled burn to prevent the slick from reaching the coastal wetlands once the winds shift.
In a controlled burn, towing boats and fire-resistant booms are arranged in a U shape to contain spilled oil before it is ignited, according to a description of the oil-containment measure (PDF) on the Web site of the U.S. National Oceanic and Atmospheric Administration, which is aiding in the spill response. The process may be repeated multiple times.

Indeed, Landry said that burning would remain a tool under consideration as long as oil was still leaking.

Authorities are drawing heavily on a 1993 experiment conducted off the coast of Newfoundland, Canada, which showed that this type of controlled burn can eliminate 50 to 99 percent of the oil collected.

The heat generated by the burning oil—a temperature of 1,800°F (982°C) was measured at the top of the boom at the Newfoundland burn—will cause the smoke to rise several hundred to several thousand feet and at the same time be carried away by the prevailing winds, NOAA's report said.
According to the National Geographic article, the effects of a controlled burn of the oil slick would be similar to a forest fire. The fire would generate smoke containing carbon dioxide, water vapor, and particulate matter. I would be concerned about birds migrating over the Gulf, but the Coast Guard seems to think the risk is minimal.
The prospect alarmed fisherman and ecologists along the Louisiana coast. Gov. Bobby Jindal requested that the Coast Guard set up protective booms around several wildlife refuges in the Delta.

Those delicate coastal rookeries and estuaries factor into the consideration for the surface burn. Such a burn would most likely ease the impact on wildlife.

The oceanic agency issued a guide to the burn that advised as follows:

“Based on our limited experience, birds and mammals are more capable of handling the risk of a local fire and temporary smoke plume than of handling the risk posed by a spreading oil slick. Birds flying in the plume can become disoriented, and could suffer toxic effects. This risk, however, is minimal when compared to oil coating and ingestion.”
Meanwhile, the spill is leading to questions about the Obama administration's plans to open more of the coast to offshore drilling and about plans to expand drilling as part of the proposed energy and climate legislation. Some previous supporters of offshore drilling, such as Charlie Crist, are rethinking their positions.