Eco-radicals want the end of air transport and heavily mediatize their modal switch to rail or sail for long-haul travel. Facing such a systemic threat, the aviation ecosystem, presently responsible of 3% of global CO2 emissions, has committed to net zero emissions by 2050. This is an objective that can only be met by the generalized use of Sustainable Aviation Fuels (SAF), the low-carbon version of kerosene extracted from crude oil which has propelled airplanes since the 1950s.
Industrialization of SAF production is on the way, relying today on the mature HEFA pathway, hydrogenation of lipids, edible vegetable oils or residuals such as used cooking oil and animal fats. The HEFA approach faces questions on the sustainability of such a production mode when highly controversial edible oils, like palm or soy oil, are used, which may limit the extent of its deployment beyond meeting initial SAF demand.
A less mature SAF production pathway, ASTM certified but in need of industrial demonstration, is second in merit order: alcohol-to-Jet (AtJ). AtJ could complement HEFA for additional SAF demand if alcohols can qualify. Ethanol is a staple bio-component, commercially produced in large volumes for more than 50 years for road transport as a carbon footprint mitigator, a usage with an uncertain future due to the rise of electromobility. Which makes an alternative usage in air transport attractive for producers.
Qualification for sustainability: Two issues are at the heart of the criticism of biofuels by environmental NGOs. The first is insufficient CO2 emission abatement and the second, production on agricultural land that is suspected to cause food security ripple effects in the world. Some ideologically-minded regulators, obligingly nudged by airlines fearful of media attacks of “greenwashing”, prefer to listen to these arguments rather than recognize the merits of biofuels that provide real CO2 emission reduction (measured by Life Cycle Analysis (LCA)), improved energy security (local production), and economic gains (local employment, foreign exchange savings from lower imported energy). Can ethanol respond to the criticism, based on sound scientific ground?
On CO2 emission abatement, progress over time is undeniable, significant and on-going as shown in this chart comparing GHG savings under the Renewable Energy Directive (RED I and II).
The graph above shows that on average, ethanol produced in Europe from sugar beets or cereals has reached some 77% CO2 emission reduction compared to fossil gasoline. Additional measures, like biogenic CO2 capture and sequestration or re-use (to produce e-fuels?), can get this performance beyond 100%, not only making ethanol carbon neutral, but also possibly neutralizing the additional CO2 emissions from the downstream transformation of ethanol into SAF in the AtJ pathway, making AtJ SAF carbon-neutral or carbon-negative.
On the agricultural land grab charge, rhetoric comes into play, meaning regulators should use their common sense to arbitrate between conflicting visions regarding the use of land. First, a reminder. In the EU, first-generation biofuels like ethanol have been facing since 2015 a regulatory limitation in terms of incorporation, at 7 %, a political compromise supposed to contain their impact on agricultural land use, a.k.a. indirect Land Use Change (ILUC). Below is the official definition of ILUC given by the European Commission:
Indirect land use change (ILUC) = displacement of agricultural production into non- croplands (e.g., grasslands and forests) due to the destination of croplands previously used for food agricultural production having been shifted to the production of non-food bio-based products (e.g., biofuels). Indirect land use change risks causing an increase in greenhouse gas emissions because non-croplands such as grasslands and forests typically absorb high levels of CO2. By converting these land types to cropland, negative environmental effects may occur, including increase of atmospheric CO2 levels, and biodiversity loss.
This definition implies ILUC can only be modeled not directly measured. Scientific modeling has taken place and indisputably confirmed that ethanol produced from sugar beets generates zero ILUC, when taking into account the use of by-products as feed (pulps replace imported soy meal). On top of this, it must be noted that this crop only uses 1% of the useful agricultural land surface in France, for instance.
So, sugar beet-based ethanol-to-jet SAF can soon be carbon-neutral and has no impact on food security in the world. While Brussels-based, out of touch with reality, regulators may well impose SAF to be “non-food”, the rule of subsidiarity in the EU passes the buck to Member States for enacting effective law, which bodes well for ethanol-based SAF in countries with a strong agricultural culture, no pun intended here, that will be honest and pragmatic enough to recognize the value of the arguments laid out above. It may take some time to advocate to that purpose but climate can be the eventual winner by opening up a large, local, resource potential for sustainable aviation.
Philippe Marchand is a Bioenergy Steering Committee Member of the European Technology and Innovation Platform (ETIP).