Airlines have made sustainable aviation fuel (SAF) deployment the linchpin of their commitments to reach net-zero emissions by 2050.
But in a recent report, an environmental think tank detailed lobbying efforts undertaken by airlines in partnership with ethanol producers that the think tank says attempt to water down the sustainability criteria in the SAF federal tax credit program, created last year as part of the Biden administration's Inflation Reduction Act.
Industry trade groups, however, say the effort isn't clandestine and note that the criteria for which they are advocating mirrors what Congress mandated be applied to nonaviation biofuels in that federal tax credit program.
Supporting their cause is a bipartisan group of senators, mostly from large corn-producing states in the Midwest.
To spur U.S. SAF production toward a target of 3 billion gallons annually by 2030, producers and air carriers receive tax credits of between $1.25 and $1.75 per gallon for SAF sales and usage, depending upon how much the fuel improves upon lifecycle greenhouse gas emissions compared with standard kerosene-based jet fuel. To qualify for the credit, the SAF has to offer a lifecycle emissions reduction of at least 50%.
In its report on SAF-related lobbying activities, the think tank InfluenceMap, which analyzes corporate influence over climate policy, argues that the trade groups Airlines for America (A4A) and the Renewable Fuels Association (RFA), as well as individual trade group members, are pushing for the Treasury Department to accept a lifetime-emissions calculation criteria that is weaker than the methodology included in the Inflation Reduction Act.
"The U.S. aviation sector appears to be pursuing a policy engagement agenda to get SAFs incentivized at any cost, including promoting policy amendments that risk stimulating SAF production with little, if any, overall [greenhouse gas] emission-saving contribution," the study's authors wrote.
As laid out in the authorizing legislation for the tax credit program, lifecycle SAF emissions are to be calculated under the methodology established by the U.N.'s aviation arm, the International Civil Aviation Organization (ICAO), or "any similar methodology."
A4A and the RFA are arguing that Treasury should accept as a similar methodology the calculation system developed by the Department of Energy that is known as GREET. That's the methodology Congress stipulated for use in the tax credit program for nonaviation biofuels.
"Using different methodologies for aviation and nonaviation fuels would disadvantage aviation and create an inconsistent approach," A4A said in an email.
GREET, noted the RFA in a statement, uses more current data than the ICAO method, which mostly relies on data published in 2012.
In a June letter to Treasury secretary Janet Yellen, the bipartisan group of 16 senators argued that preventing the use of the GREET standard would limit the role of SAF production by American farmers and "force the aviation industry to miss an opportunity to eliminate millions of tons of carbon emissions in the coming years."
At primary issue in the debate is how indirect land-use changes that come from growing corn and soy for production of ethanol-based SAF impacts the product's lifetime greenhouse gas emissions. Indirect land-use changes include crop area expansions and conversions of food production for ethanol feedstock.
InfluenceMap says that the GREET methodology attributes lower emissions to indirect land use than other methodologies. For example, said InfluenceMap analyst Lucca Ewbanks, the impact of indirect land use changes for soy are estimated at approximately one-quarter the amount under GREET than has been estimated by the EPA and the state of California.
The InfluenceMap report also mentions lobbying efforts by the RFA in which the trade group noted that under GREET the impact of indirect land use changes for U.S. corn grain are approximately a quarter of the ICAO methodology estimate.
A key difference between the methodologies, said InfluenceMap, is whether the conversion of pasture that was once cropland back into corn cropping results in carbon sequestration. The default GREET module assumes it is, while the ICAO method assumes carbon emissions go up during the conversion.
Using the GREET methodology, rather than the ICAO's, could allow the tax credit program to incentivize more corn ethanol production, says InfluenceMap, competing with food crops and increasing emissions.
Environmental advocates instead want SAF production to be focused on second- and third-generation inputs, such as used cooking oil and waste fat conversion, forestry residues and garbage conversion.
A4A, however, says that incentivizing a robust slate of SAF feedstock options is the best way to make flying more green.
"Ensuring tax credit eligibility for all pathways that can meet objective criteria based on scientifically proven models to reduce lifecycle emissions will yield the greatest chance toward meeting the grand challenge of making flying more sustainable," the trade group said.
The RFA also sharply disputes Influence Map's assertions about the GREET methodology, stating that GREET's latest models are more reflective of current technology than the dated ICAO models.
"Our advocacy efforts are focused solely on strengthening the credibility, transparency and scientific robustness of the lifecycle carbon methodology that will ultimately be used to administer SAF tax credits," RFA CEO Geoff Cooper wrote in an email.