Biomass: Hope and Hype

Unless it’s done carefully, deriving fuels from biomass could destroy crop lands through erosion, increase air pollution — and even increase our dependence on fossil fuels. For example, one of the steps in processing biomass, distillation, requires heat. In the short term, inexpensive coal may appear to be a good energy source for this, says John Reilly, associate director for research at MIT’s Joint Program on the Science and Policy of Global Change. But this would cancel out one of the primary benefits of biomass: carbon released by burning biofuels is offset by the carbon captured by growing crops, leading to near-zero total carbon emissions. Using coal for distillation would destroy this balance. In one scenario, Reilly says that “68 percent of the carbon you think you’re saving is actually being emitted through other processes.” Likewise, using gasoline or diesel to transport biomass from widespread farms and other agricultural facilities to processing centers would change the overall carbon equation.

Technology Review