Biofuels
Henry Ford (above, at the wheel of a Model T) designed his "Tin
Lizzie" to run on either gasoline or a hemp-based fuel. But with the
discovery of large crude-oil deposits in the early 20th century, oil
prices dropped and gasoline derived from the oil became Ford's and
other carmakers' fuel of choice. Unlike fossil fuels, biofuels come
from renewable resources, typically plants. Although biofuels have
many advocates, skeptics point out that they currently require too
many resources to be used on a widespread commercial basis.