November 23, 2005 11:23 AM PST
Shell, Exxon Mobil tout a cleaner fuel for megacities
Shell and Exxon Mobil are ramping up production on a fuel, called Gas-to-Liquids, that's derived from natural gas. It significantly reduces the sulfur, carbon monoxide and other pollutants that belch from car tailpipes. And although more costly than regular gas, it should help crimp the air pollution in places like Los Angeles, or in New Delhi, where diesel buses are banned.
Shell currently sells a GTL/diesel blend in 3,000 stations in Europe and Asia, but the company wants to sell a pure form of GTL to power taxis and buses in large cities.
The company has a plant in Bintulu, on the island of Borneo, that can produce 14,700 barrels a day of GTL. In addition, it is in the process of building a plant in Qatar that aims to crank out 140,000 barrels a day by the end of the decade.
With that much capacity, "we could power the taxis and buses in the top 10 megacities in the world," said Andrew Brown, Shell's country chairman for Qatar.
One of the chief advantages of GTL is it works in contemporary diesel engines. And, it can be transported and sold through the existing diesel infrastructure, so adoption won't require automakers to undertake a substantial technical overhaul.
Essentially, GTL is a modified version of a technique for turning coal into gasoline. The technique, called the Fischer-Tropsch process, was discovered in Europe in the 1920s. But instead of starting with coal, the GTL process begins with synthetic gas created in an industrial plant. The synthetic gas derives from natural gas--which is far cleaner than coal--and other materials.
"You can drink it," one Shell executive said. "You won't feel great, but you won't die."
In fact, food producers use a kosher-approved GTL derivative to line juice boxes.
The end product, depending how it is processed and what is added, contains no sulfur and fewer nitrogen compounds than standard gas. Cars that run on GTL emit less carbon dioxide. Some of the carbon dioxide benefit is lost because producing GTL creates more of the byproduct than producing normal oil does. Independent research is under way to bury carbon dioxide.
The real challenge to mass adoption of GTL is cost. It takes roughly 10,000 cubic feet of natural gas to produce a barrel of oil, an Exxon Mobil representative estimated.
Both companies are putting their GTL plants in Qatar, which sits on the world's largest natural gas reserves.