Western governments have made a wrong turn in energy policy by supporting the large-scale conversion of plants into fuel and should reconsider that strategy, according to a new report from a prominent environmental think tank.

Turning plant matter into liquid fuel or electricity is so inefficient that the approach is unlikely ever to supply a substantial fraction of global energy demand, the report found. It added that continuing to pursue this strategy — which has already led to billions of dollars of investment — is likely to use up vast tracts of fertile land that could be devoted to helping feed the world’s growing population.

Some types of biofuels do make environmental sense, the report found, particularly those made from wastes like sawdust, tree trimmings and cornstalks. But their potential is limited, and these fuels should probably be used in airplanes, for which there is no alternative power source that could reduce emissions.

“I would say that many of the claims for biofuels have been dramatically exaggerated,” said Andrew Steer, president of the World Resources Institute, a global research organization based in Washington that is publishing the report. “There are other, more effective routes to get to a low-carbon world.”