In a new study published online yesterday in the journal Science, researchers led by Elliott Campbell of the University of California, Merced modeled entire fuel systems all the way from crop cultivation to vehicle propulsion, comparing cumulative greenhouse-gas emissions for both biofuels and bioelectricity. They found that the bioelectric pathway came out ahead of both corn ethanol and advanced cellulosic ethanol made from switchgrass.
“We expected that electricity would look better than corn ethanol, but it was surprising to see that this was also the case for the more advanced second-generation ethanols,” Campbell says. “In all cases, the electricity pathway uses a lot less land to achieve the same amount of transportation.”
The study suggests than electric vehicle powered by biomass will travel an average of 81% farther than an internal-combustion vehicle powered by cellulosic ethanol if both are produced from the same area of cropland.
The results also suggest that alternative bioenergy pathways have large differences in how efficiently they use the available land to achieve transportation and climate goals.