Flex Fuel Hybrids  

WorldChanging (which I'm having trouble keeping up with these days) also has a good snippet on hybrid cars with "flex fuel" engines that will run on a variety of fuels

Fareed Zakaria's piece in Newsweek suggested that plug-in hybrids combined with flex-fuel engines could greatly reduce our dependence on petroleum. We've talked about plug-in hybrids before, so what's this about flex-fuels?

Broadly put, flex-fuel vehicles are those which can run on a variety of fuels, not just gasoline. While most gasoline engines will run acceptably on mixtures of a small amount of alternative fuel (e.g., ethanol) with gasoline, flex-fuel engines are designed to handle much greater amounts of non-petroleum fuel. "E85," or a mixture of 85% ethanol and 15% gasoline, is a flex-fuel choice with some automaker support. This article at the World Business Council for Sustainable Development provides an overview of non-petroleum fuel options; generally speaking, the ones which include "mixed" or "blended" forms in the description are suitable for flex-fuel use.

An advanced flexible engine technology, HCCI, offers a greater range than most flex-fuel engines. As we noted in August, Fiat will be introducing an HCCI engine design in Brazil able to use four different fuels -- gasoline, diesel, ethanol and natural gas. HCCI engines have significantly lower emissions and much greater efficiency than regular internal combustion engines, but they're also much trickier to design and maintain.