Within the last five years, concern over both global climate change and the economic and national security implications of U.S. oil consumption has created an interest in alternate sources of liquid fuel, namely, “biofuels” derived from agricultural crops. What began as an exciting possibility has unfortunately become an example of how well-intentioned but ill-conceived policy can stand in the way of other, perhaps better, ideas.

Biofuels were originally conceived as the fuel of choice for automobiles when the internal combustion engine was first developed. Biofuels later re-emerged as a possible alternative to petroleum for our liquid fuel needs. Proponents touted biofuels as carbon neutral, and possible to generate not only from crops like corn and sugar cane, but also from agricultural or industrial waste like wood chips and bagasse, leftover material from sugar-cane production in southern Gulf states like Louisiana. Another potential benefit was that the fuel could be homegrown, providing an attractive alternative to foreign sources of oil.

Federal programs to sponsor research into biofuels expanded. Oil companies started partnering with universities to investigate the possibilities. Increasingly, research revealed not only potential but also pitfalls. Some critics argued, for example, that in a full life-cycle analysis, biofuels were not, in fact, carbon neutral. Instead, they said, the petroleum-based inputs required to grow, harvest, and transport the crops, and the energy required to process them into fuels, resulted in significant carbon emissions and net energy loss. But the question of the net energy balance of biofuels was hardly the only potential concern.

First-generation biofuels use primarily corn as a feedstock – a crop grown in abundance in the United States. Concerns arose over soil erosion, carbon emissions from land-use change, and impacts on water quality and quantity. Add questions about whether the renewable fuel standards were realistically achievable anyway, given how much feedstock we can actually grow, and given other demands for agricultural products such as “food.” Still, the policy train was already leaving the station.

In 2007, the federal government introduced the first Renewable Fuel Standards, which required that by 2012, at least 7.5 billion gallons of renewable fuel must be blended into motor-vehicle fuel sold in the United States. Many states, including California, followed suit by launching their own plans for renewable fuel mandates. Now, new research suggests that there may be a better use of bio-based fuels than liquid applications.

Generating electricity from those feedstocks is considerably more energy efficient – and potentially more carbon efficient – than using them as sources of ethanol. Researchers at the University of California-Merced and Stanford made that assessment, published earlier this month in Science, through a life-cycle analysis of corn-based, cellulosic and advanced biofuels.

The renewable fuel standards, however, require the use of biofuels as motor-fuel additives. In fact, the second-generation federal Renewable Fuel Standard, “RFS2,” the proposal for which was unveiled this month, calls for an even more aggressive use of biofuels in the nation’s motor-vehicle fuel supply, more than doubling the 2012 biofuel requirement in motor-vehicle fuel to 15.2 billion gallons per year.

The renewable fuel standards are an example of governments not only cherry-picking a particular energy source, but also mandating how that energy source should be used. Certainly, policy need not necessarily wait for a fully matured and researched industry to be up and running. But at the same time, policy shouldn’t lock us into a particular use of a particular technology without regard to remaining uncertainties or to future development of better options.