Cellulosic ethanol's highly subsidized failure

Actual U.S. production of cellulosic ethanol and other cellulosic liquids compared to the targets for cellulosic biofuels specified in the Renewable Fuel Standard

Cellulosic ethanol, once a great green hope for cutting petroleum use and CO2 emissions, has been a bust. The chart above compares the volume of cellulose-based liquid biofuels (largely ethanol) actually used in the United States to the targets for such fuels set by Congress when it expanded the Renewable Fuel Standard (RFS) in 2007. Note the logarithmic scale on the vertical axis; the gap between promise and reality is so large that actual production would be barely visible on a linear scale. 

The fuel has been delivered at levels of no more than about 0.1% of (three orders of magnitude less than) the volumes on which the RFS was premised [1]. This chart does not include cellulosic biogas, which EPA re-classified to qualify for RFS compliance purposes and has seen recent production of around 500 million ethanol-equivalent gallons. However, such "renewable natural gas" is not in the spirit of the law, which envisioned liquid biofuels that could be readily used in motor vehicles. The 2019 RFS target for cellulosic biofuels was 8.5 billion gallons, set to reach 16 billion gallons by 2022. But in 2019, before the pandemic-related drop-off in 2020 for nearly all forms of energy, only 9.8 million gallons of cellulosic ethanol were tallied by EPA.  

Cellulosic ethanol has been the holy grail of the alternative fuels world. The concept is that it can be made from the non-edible materials that comprise the bulk of plants, including crop residues as well as purpose-grown energy crops such as switchgrass, or from organic wastes. Other promised cellulosic biofuels include "grassoline," which wouldn't face the limitations and other problems caused when blending oxygen-bearing, water-loving ethanol into petroleum based gasoline, and similarly compatible bio-based diesel and jet fuels. 

Claiming to side step the food-versus-fuel problems of crop-based biofuels such as ethanol from corn or sugarcane and biodiesel from soy or palm, cellulosic ethanol became a darling of many environmentalists and green-leaning policymakers. Billions of gallons of cellulosic biofuels were supposed to account for the bulk of a fully-ramped-up RFS. Cellulosic ethanol was also a key premise for California's so-called Low Carbon Fuel Standard (LCFS), which--recognizing the cellulosic ethanol bust--has since largely segued into yet another way to promote electric vehicles. 

For many decades, programs at the U.S. Departments of Energy and Agriculture ploughed billions of public dollars on research, development, demonstration and start-up facilities for cellulosic biofuels. Substantial private capital also poured into the quest, as seen in the multiple high-profile ventures by Vinod Khosla (among others) that have since collapsed. Developing commercially viable ways to produce cellulosic biofuel was a top goal nearly 15 years ago when BP made news by committing a half-billion dollars to launch the Energy & Biosciences Institute. That R&D center has since refocused its biofuel efforts largely on other pathways, none of which have yet become economically feasible. 

Others have written further about this taxpayer-funded failure. Just under a decade into the RFS-driven quest, the cellulosic struggles were noted even while touting hope for Project Liberty, a generously subsidized facility that began making a dribble of fuel in 2014. It was shuttered in 2020, joining the long list of failed projects that tried to produce economically viable cellulosic ethanol. In short, what had been hailed as the nation’s most ambitious program to cut global warming emissions from motor vehicles collapsed despite a bipartisan effort that involved billions of taxpayer and corporate dollars.  

[1] U.S. Environmental Protection Agency, Public Data for the Renewable Fuel Standard, Spreadsheet of RIN generation and renewable fuel volume production by fuel type from September 2021, via https://www.epa.gov/fuels-registration-reporting-and-compliance-help/public-data-renewable-fuel-standard accessed 27 Oct 2021.