Carnegie Mellon University
April 07, 2015

Carnegie Mellon Researchers Call for Broader U.S. Renewable Fuel Standard

By Tara Moore / 412-268-9673                 

In a paper recently published in Environmental Science and Technology, a team of Carnegie Mellon University researchers argue for a broader renewable fuel standard on the basis that the regulation’s current focus is damaging growth of the renewable biomass industry in the United States.

Established in 2007, the U.S. Renewable Fuel Standard (RFS2) was designed to promote use of renewable biofuels in domestic transportation by requiring refiners, blenders and importers to meet certain biofuel percentages that will increase incrementally into 2022. However, due to a lack of supply and demand, it is unlikely that the U.S. will be able to meet these increased percentages.

The prediction puts RFS2 in danger of being repealed, an action that could cripple  development of second generation biofuels that rely on market incentives to propel research, as well as bio-ethylene, a key ingredient in most common plastics.

As it currently stands, the RFS2 focuses exclusively on the transportation sector. The team’s research suggests the narrow focus is choking the standard’s potential and killing the future of the U.S. biofuel industry in the process. 

Their paper examines the greenhouse gas (GHG) implications of a more flexible policy that covers the production of renewable bio-based chemicals and includes credits for chemical use of bio-ethanol to produce bio-ethylene. A key finding of their research is that using ethanol to produce bio-ethylene achieves similar GHG savings to using bioethanol as a fuel. 

The paper asserts that replacing the renewable fuel standard with a broader renewable material standard could add flexibility to the policy without compromising GHG reduction targets, one of the overall intentions of the RFS2 regulation. As ethylene is the organic chemical with the world’s highest production volume, a more inclusive RFS2 could have great impact.

Co-authors on the paper include Daniel Posen, a doctoral student of civil and environmental engineering (CEE) and engineering and public policy (EPP); Michael Griffin, associate research professor of EPP; Inês Azevedo, associate professor of EPP; and H. Scott Matthews, professor of EPP and CEE.

According to Posen, increasing the flexibility of RFS2 would be a win for everyone.

“Ethanol producers win by expanding their potential sales market, gasoline blenders win due to the increased flexibility in meeting their obligations, and chemical companies win by being able to participate in the market for renewable fuel credits,” Posen said.

“We found that there are large environmental benefits for the production of both ethanol fuel and polyethylene plastic from Brazilian sugarcane or U.S. switchgrass,” Posen added. “In contrast, we found that products from corn grain do indeed have higher GHG emissions than products made from fossil fuels. This last finding is likely to be quite controversial since the U.S. ethanol industry is currently heavily reliant on corn.”

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