The RFS Really Did Shatter the “Blend Wall” for Ethanol

Cindy Zimmerman

By Scott Richman, RFA Chief Economist

Not so long ago, renewable fuel critics claimed that due to purported infrastructure and vehicle constraints, the ethanol content in gasoline simply could not exceed 10.0%. They referred to this supposed limitation as the “blend wall,” and for several years that terminology found its way into virtually every debate about ethanol, the Renewable Fuel Standard (RFS), and higher-level blends.

But no one really talks about the “blend wall” anymore. Why?

Because ethanol’s blend rate has exceeded 10.0% every year since 2016 and hit a record 10.38% in 2022, according to data from the U.S. Energy Information Administration. The experience of the past several years shows that the “blend wall” was nothing more than a fictional barricade. In fact, as this analysis shows, the U.S. market is on pace to consume some 630 million gallons of ethanol over and above the so-called “blend wall” this year, proving once again that the 10.0% threshold is not a real barrier.

Given this reality, critics changed their tune to say that the blend rate would not have exceeded 10% if not for the RFS, the primary federal program that has promoted the usage of biofuels since 2005. While this argument de-emphasizes other factors that have contributed to the rising blend rate, such as ethanol’s cost-competitiveness compared to gasoline and especially other sources of octane, it is consistent with the intent behind the enactment of the RFS.

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Ethanol, Opinion, Renewable Fuels Association, RFA