Americans burn through 140 billion gallons of gasoline a year. And even if drivers switch to more fuel-efficient cars and trucks, the nation’s fuel needs are expected to increase by a fifth over the next 20 years, thanks to dramatic increases in car and airplane use. Which is why, in addition to developing solar, wind and geothermal energy, policy makers, including President Barack Obama, are advocating biofuels to transform the transportation culture.


