According to a new study, that compared the greenhouse gas emission reductions of corn ethanol and those of crude oil production and fracking, corn ethanol’s carbon intensity is declining while the carbon intensity of petroleum is increasing. The study was conducted by Life Cycle Associates and found that the carbon impacts associated with crude oil production continue to worsen as more marginal sources of fuel are introduced into the fuel supply.
According to the report, “As the average carbon intensity of petroleum is gradually increasing, the carbon intensity of corn ethanol is declining. Corn ethanol producers are motivated by economics to reduce the energy inputs and improve product yields.”
The study, commissioned by the Renewable Fuels Association (RFA), found that average corn ethanol reduced greenhouse gas (GHG) emissions by 32 percent compared to average petroleum in 2012. This estimate includes prospective emissions from indirect land use change (ILUC) for corn ethanol. When compared to marginal petroleum sources like tight oil from fracking and oil sands, average corn ethanol reduces GHG emissions by 37-40 percent.
As more unconventional crude oil sources enter the U.S. oil supply, and as corn ethanol production processes become even more efficient, the carbon impacts of ethanol and crude oil will continue to diverge. The study predicts that by 2022, average corn ethanol reduces GHG emissions by 43-60 percent compared to petroleum.
“The majority of unconventional fuel sources emit significantly more GHG emissions than both biofuels and conventional fossil fuel sources,” according to the study. “The biggest future impacts on the U.S. oil slate are expected to come from oil sands and fracking production.” In the absence of biofuels, “…significant quantities of marginal oil would be fed into U.S. refineries, generating corresponding emissions penalties that would be further aggravated in the absence of renewable fuel alternatives.”
The study also reveals several fundamental flaws with the GHG analysis conducted by the Environmental Protection Agency (EPA) for the expanded Renewable Fuel Standard (RFS2) regulations. Continue reading