The world's economy is acquiring a new energy addiction: biofuels.
Crop-based fuels such as ethanol and biodiesel are quietly becoming a crucial component of the global energy supply, despite growing concerns about their impact on the environment and world food prices.
Biofuels production is rising rapidly, while other fuel sources are failing to keep pace with demand. As a result, biofuels are making up a larger portion of the world's energy-supply gap than many analysts expected. That means the debate over biofuels probably will shift from whether they are good or bad to the more difficult question of how to make sure their production keeps growing -- without wreaking economic and environmental havoc.