Ask Pablo: Why Didn't They Just Burn The BP Oil Spill?
Image Source: marinephotobank
Dear Pablo: I am very disturbed by the massive oil spill in the Gulf. Why didn't BP or the Government just burn it all before it began reaching land? Surely this would have been a lesser evil.
If we weren't already there before, BP's underwater gusher in the Gulf has our collective eco-anxiety approaching 11. Not only is the scale difficult to comprehend (3,850 square miles as of 4/30/2010) but, unlike the Exxon Valdez spill, this spill keeps on going at a rate of 1,000-5,000 barrels per day. Burning such large quantities of oil would be a dirty proposition, blackening skies and severely impacting air quality in the Southern US, but wouldn't it be better than letting it coat hundreds of miles of beaches, endangered seabirds, oyster beds, and protective barrier wetlands?At roughly 9.4 kilograms of CO2 per gallon of crude oil, burning the already-spilled 1.6 million gallons (estimate as of 5/2/2010) would theoretically turn it into 15,000 metric tons of greenhouse gasses. This is equivalent to the estimated daily emissions from yesterday's news: the Eyjafjallajoekull volcano in Iceland. Since crude oil is unrefined, contains various impurities, and because open combustion does not achieve ideal combustion conditions, the combustion emissions would also include various undesirable gasses including SOX, NOX, VOCs, particulate matter, N2O and probably some mercury too. But tell that to the birds that will have their feathers tarred, the fisherman that will loose their way of life, and the tourism industry of the Gulf Coast and you will soon realize that burning of the oil would be the lesser evil.
Burning An Oil Spill
Unlike the gasoline that is distilled from it, crude oil has a relatively high flash point of 140°F. The flash point is the temperature at which a substance can vaporize to form a ignitable mixture in air. In order to sustain combustion the crude oil must be maintained at or above the flash point. Unfortunately the sea surface temperature near the oil spill is in the mid to low 70's and the air temperature is only slightly higher. This means that the additional heat to maintain the combustion needs to come from the combustion itself. Since the oil slick is spread out and quite thin, this surface layer does not contain enough chemical potential energy per square foot to sufficiently heat the oil adjacent to it.
You may have seen that there were attempts made at burning off some of the oil before it reached shore. In order to sustain the combustion, boats with booms were used to corral enough oil to achieve combustion that could be sustained. Sadly, by one estimate heard on National Public Radio (NPR), only about 3% of the oil could have been burned off in this way. To make matters worse, choppy seas have disrupted any burning operations over the last few days and oil has since made it to shore.
What Else Can Be Done?
There has been much talk of chemical dispersants, like some magical substance that can just make the problem go away. These dispersants work to transform a surface-coating oil slick into individual oil droplets that will mix into the sea water to be later biodegraded by naturally occurring micro-organisms. The military is providing support with two C-130 aircraft that can cover 250 acres per flight, up to three times per day. This is a total of 1,500 acres, or 2.3 square miles, compared to the 3,850 square miles already covered in oil. According to White House Press Secretary Robert Gibbs nearly 143,000 gallons of dispersant have been deployed already and an additional 68,300 gallons are available (BP is said to have already purchased 1/3rd of the world's supply). Unfortunately these chemicals present their own environmental concerns. In terms of supply, effectiveness, and net environmental benefit, chemical dispersants don't seem to be the magic bullet that we are looking for either.
When it comes to something as catastrophic as a major oil spill the best solution is prevention. Since it is a little bit too late for that the next best thing that we can do is to prevent future disasters like this by leaving the deep sea oil in the seabed and instead spending that money on long term sustainable energy sources that don't posses the potential for such widespread destruction and disruption.
Pablo Päster is a weekly columnist for TreeHugger.com, an experienced greenhouse gas engineer and the Senior Environmental Program Manager at Hara Software. Send your questions to Pablo(at)TreeHugger.com or submit the via this form and connect to his RSS feed.
More TreeHugger Articles On The Oil Spill:
Burn It?! Coast Guard Now Considering Setting Oil Slick on Fire. What Are the Pros & Cons?
BP Gulf Oil Spill Cheat Sheet: A Timeline of Unfortunate Events
The Anatomy Of An Oil Spill Cleanup: What Works And What Doesn't
Gulf of Mexico Oil Spill: The What, When and Where... and How You Can Help
How Stuff Works: How Do You Clean Up An Oil Spill?