Efficiencies "could shrink projected U.S. oil use in 2025 by more than half"...

streamlined our factories and, perhaps most important, got more work out of a gallon of gasoline by imposing strict fuel economy standards (which, regrettably, have not been seriously updated for three decades).

There is a lot more efficiency to be wrung out of the system. Anyone who has suffered recently through a blackout or brownout knows first-hand how old and inefficient much of the nation's transmission grid is. The same is true of things we do not normally regard

Lovins points out that despite 119 years of refinement, the modern car remains 'astonishingly inefficient'.

as old or inefficient.

Take, for instance, the automobile. Lovins points out that despite 119 years of refinement, the modern car remains “astonishingly inefficient” , with only 13 percent of the energy even reaching the wheels. Constructing cars from light-but-strong materials like advanced polymer composites, he argues, would increase mileage dramatically. Make that same car a plug-in hybrid, running partly on gasoline and partly on advanced batteries that can be recharged at home overnight, and pretty soon consumers could be driving cars capable of well over 100 miles per gallon.

Overall, Mr. Lovins insists, full adoption of efficient vehicles, buildings and industries could shrink projected U.S. oil use in 2025 by more than half   (that is, about 14 million of a projected 28 million barrels a day),  lowering consumption to pre-1970 levels. And we wouldn't even need renewable fuels to get there.

But wouldn't it be wonderful if we had such fuels? Without renewables, we'll still end up burning (albeit much more efficiently) the same coal and natural gas that we burn today in our power plants and the same fuel oil that we burn in our cars and trucks. And it is precisely these carbon-based fossil fuels that we must distance ourselves from if we really want to come to grips with our dependence on foreign oil and with global warming.

The commodity that may be best positioned to help the United States break its addiction to oil is already growing in America's fields and forests — plants and trees, known collectively as biomass. Fuels derived from biomass can be produced either by converting sugar or starch crops to ethanol, or by converting soybean and other plant oils to biodiesel.

Of these two biofuels, ethanol is the most promising. Despite biodiesel's growing popularity (the country and western singer Willie Nelson promotes it assiduously ), only about 75 million gallons were produced in 2005, compared to nearly 4 billion gallons of ethanol.

President Bush mentioned ethanol in his State of the Union address this year.