OPINION: Ethanol dominates in clean air contest

By Chris Bliley, Growth Energy | May 01, 2020

When it comes to transportation emissions, newsrooms around the world generally preserve their biggest headlines for the urgent, high-stakes battle against climate change. Biofuels are a major part of that conversation, and the U.N. Intergovernmental Panel on Climate Change (IPCC) reports that a sharp uptick in biofuel consumption is vital to holding temperature changes below 1.5 degrees Celsius. In fact, the IPCC projects that we’ll need to boost biofuels from two to nearly 15 percent of the transportation mix globally. But that’s not the whole story.

Beyond the global climate, the core benefits offered by ethanol to local air quality and human health remain top of mind for regulators and scientists alike. From California to Indonesia, leaders are seeking solutions to the ongoing challenges posed by particulate emissions, ozone, and volatile organic chemicals (VOCs). According to the World Health Organization, an estimated 4.2 million premature deaths globally are linked to air pollution, marking it as one of the world’s top killers.

In the United States, about 98 percent of motor fuel now contains 10 percent ethanol, a trend that was solidified under the 1990 Clean Air Act Amendments and the 2005 Renewable Fuel Standard (RFS). Since 1990, that progress has helped the U.S. cut concentrations of ozone by 21 percent and particulate matter (PM 2.5) by 26 percent.

Now automakers and regulators are looking at the next generation of fuel blends, which can power engines with higher compression ratios, delivering more miles from every gallon. Those advancements require higher-octane fuels, beyond the regular 87 common at most fueling stations.

To get an efficiency boost, refiners will have to make a choice – either adopt higher ethanol blends or add an increasing volume of toxic aromatics to our fuel, including benzene, toluene, ethylbenzene, and xylene. The choice is clear, and new research is helping to demonstrate the incredible advantages of plant-based ethanol, compared to the petroleum-based alternatives.

Most recently, scientists at the Center for Environmental Research and Technology at the University of California, Riverside completed a landmark study on the toxic and particulate emissions of fuel blends. Supported by Growth Energy, the peer-reviewed study (Part One, Part Two), “The Impacts of Gasoline Aromatic and Ethanol Levels on the Emissions from Gasoline Direct Injection (GDI) Vehicles,” examined eight fuels, with higher and low aromatic levels, and ethanol levels ranging from 0 percent (E0) to 20 percent (E20).

Unsurprisingly, the study found that an increase of petroleum-based aromatics resulted in significantly higher emissions. Aromatics, like xylene and toluene, are additives used in fuel as octane boosters instead of ethanol.

In fact, it found that aromatics, not ethanol, play a dominate role in the formation of toxic emissions linked to cancer, as well as neurological, cardiovascular, and reproductive damage. It also found that aromatics drive the most significant increases in particulate emissions, which cause asthma and contribute to heart and lung disease.

In addition, petroleum-based aromatics were linked to higher ozone-forming potential, carbon dioxide, and VOCs like benzene, a known carcinogen.

At the same time, researchers found that ethanol plays a major role in reducing dangerous carbon monoxide emissions, an odorless gas that can cause sudden illness and lead to death. In part, that is because ethanol introduces additional oxygen to fuel mix, “leading to a more complete combustion,” noted the authors.

The key takeaway here is that small changes in our fuel mix can have a major impact on the future of our health, as well as our climate. And while “[e]thanol has a higher octane rating than gasoline, making it an attractive blending component,” according to researchers, the benefits of biofuels don’t stop in the engine. Clean, renewable ethanol remains the single most affordable and abundant alterative to aromatics, which “played a more dominant role in emissions formation than ethanol content, indicating multiple formation pathways for these pollutants.”

Now that the U.S. has approved year-round sales of E15 for all light-duty vehicles model year 2001 and newer, we’re already seeing more and more drivers take advantage of higher ethanol blends. Hopefully, as we move toward more low-carbon biofuels on the global stage, drivers across the world will enjoy the same opportunity to breath healthier air.
~Chris Bliley, Sentior Vice President of Regulatory Affairs at Growth Energy, America’s largest trade association representing supporters and producers of ethanol.