In the trucking business, diesel stacks can come in many shapes and sizes –modified, chromed-up, hidden behind fairings, and all sorts of things. From the factory these days, though, they all share a common attribute — the gas coming out of them holds little resemblance to the sooty, particulate-laden belching commonly seen in all sorts of television broadcasts about coming green technology. Most recently, in a story about yet another start-up algae-biodiesel and alternative fuel producer on the News Hour With Jim Lehrer, an old jalopy of a cabover is pictured during a sort of montage about dirty technology, followed by your typical stack close-up, belching smoke.

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