As the controversy over corn-based ethanol tells us, biofuels—made from crops and used to replace conventional fuel—are not necessarily more environmentally friendly than oil. Producing biofuels may use fossil fuel, for instance, through farm machinery and oil-based fertilizer. Land used for biofuel crops may also displace land that could be used for food, indirectly leading to deforestation. Since forests keep carbon dioxide out of the atmosphere, the environmental impact is bad locally and globally.
A new MIT study highlights the complexity. James Hileman and his team analyzed 14 jet fuel sources using a complete lifecycle analysis of every aspect of production and combustion, and concluded that some biofuels can ultimately emit as much as 10 times more carbon dioxide than conventional sources. Making matters even trickier, the type of land used to grow crops, as well as the kind of crops used, are crucial to the total impact. “You can’t simply say a biofuel is good or bad,” Hileman says, “it depends on how it’s produced and processed.”
Such studies illuminate the haphazard nature of the current approach to energy. Calculating total impact of any fuel source is complicated, with biofuels especially. Ideally, society would calculate and compare the total impact of different fuel sources and make decisions based on cost-benefit analysis. What’s needed is a national—or even international—inventory of different fuels that gives complete lifecycle analysis of total impact. A price on carbon (and, possibly, on other environmental impacts) would do even more to push us toward energy use that gives us maximum return on our investment.
We already know about some high efficiency biofuels that should be more widespread. Fuel made from sugarcane is powering Brazil’s transportation, making it an oil-free country. The tropical plant jatropha is also an excellent, if underutilized, biofuel source. Probably the greatest potential comes from algae, an extremely potent and environmentally friendly fuel source. We need to be moving rapidly on research and, where viable, production of all these high efficiency biofuels. Unfortunately, we are moving more rapidly toward the alternative, to extract oil from ever more difficult places in ever more dangerous ways, wreaking havoc on the environment for a source that will inevitably run out.