Warren Mitchell, of Clean Energy, said it will be very difficult for petroleum products to meet emissions requirements in the future and that $80+ a barrel oil cost will push alternative fuel growth. Clean Energy hopes that a lot of the growth comes from natural gas produced in the U.S. used to power natural gas vehicles, like the Honda Civic GX (named ACEEE's Green Car for 2007). Mitchell said that switching to natural gas can result in annual fuel savings of between $4,400 for a taxi to $14,300 for a municipal bus. Sure, converting the engine costs money up front, but the cost will generally be paid back quickly (in a year or so) for many operators.
Paul Wuebben, clean fuels officer of the South Coast Air Quality Management District, echoed the developing mantra of these presentations that there is no one alternative fuel technology that everyone should be pursuing. His "interesting trends to watch" include a possible Toyota PHEV with flex-fuel technology, the "GM E-Volt platform" (sic), A123's lithium batteries and more.
Other panels provided a little more somethin' somethin', and that takes longer to write about (and process audio, etc.), so look for them in a little while.