From Well to Wheels

A look at ethanol's life cycle emissions.

- By Alex GrayNew Products [e-mail]

Corn ethanol has been the standard for biofuels in the United States since the Renewable Fuel Standard (RFS) was introduced in 2005. Carbon pipelines have been positioned as the next step the ethanol industry needs to sequester carbon, receive tax credits, and be poised for growth, including in new areas such as sustainable aviation fuel. In our series on carbon pipelines, we have covered how companies are working to establish pipelines across the Midwest. We also looked at how farmers can navigate eminent domain use when pipeline construction comes closer to reality.

For this story, we set out to directly compare the life cycle of greenhouse gas (GHG) emissions — from well to wheels — of ethanol and gasoline, and how carbon pipelines factor into the future of ethanol as a viable, low-emission fuel. This turned out to be more difficult than expected. Few recent independent studies have been conducted removed from the goal of adopting ethanol as a clean energy source in the U.S. There are so many different approaches to measure well-to-wheel emissions, it's almost impossible to find an agreed-upon carbon intensity (CI) score among various studies and stakeholders. The U.S. government uses the Department of Energy's Greenhouse Gases, Regulated Emissions, and Energy Use in Technologies (GREET) model.

Mark Heckman is vice president of sales and marketing at Edeniq, Inc., a California-based biotechnology company, and formerly ethanol services director at EcoEngineers, an Iowa-based engineering consultant. “In the carbon world, people talk about system boundaries — the handoff of where emission measurement starts and when it stops,” Heckman said. “The GREET model is a quick tool that pulls all these emission factors into it, and uses the science that's coming out of the Department of Energy and Argonne National Laboratory to state acceptable practices or levels to use, if you take farm practices as a whole.”