What are airlines doing about food waste


Researchers at the University of California at Berkeley say they have developed a new jet fuel that drastically reduces the amount of carbon produced by airplanes. And not only that: The production of the alternative fuel could also reduce methane emissions - another greenhouse gas - that arise in landfills.

Currently, aircraft must refuel with a special type of fuel that is subject to many stringent requirements and criteria in order to achieve the performance and reliability required for large aircraft. Often these fuels are petroleum based or made from blends with synthetic fuel sources. The latter in particular is becoming increasingly popular due to the increased cost of aviation fuel. However, many of these synthetic fuels are obtained from fossil fuels just as much as coal or natural gas.

Now the University of California has thrown a new competitor into the race: organic waste, i.e. organic, biodegradable food waste such as fruit and vegetable peel, coffee powder, meat and bones, leftovers, leaves and egg shells. These "waste products" were previously used to develop biodiesel for vehicles on the ground, but were considered uneconomical and inefficient for aviation fuel. A lot of organic waste also goes into the production of methane gas.

However, the authors of a new study recently published in the Proceedings of the National Academy of Sciences (PNAS) discovered a method by which the natural decomposition process of organic waste can be interrupted to produce short-chain fatty acids, or even volatile fatty acids ( VFA), as opposed to producing methane (CH4). These fatty acids can then be passed through some form of catalytic conversion to produce two different types of sustainable paraffin.

In combination, 70 percent of the mixture could be mixed with regular jet fuel to create a more environmentally friendly hybrid that still adheres to aviation authority standards. Although previous jet fuels were developed using so-called "dry" waste, this is the first time that moist bio-waste, including manure and sewage, has been used in the process. Due to the complexity and high moisture content of the waste, its use has typically been limited to methane production through anaerobic digestion.

According to the study, the new mixture reduces aircraft CO2 emissions by 165 percent compared to fossil fuels. This figure not only includes the reduction of the carbon produced, but also the avoided emissions from the transport and disposal of organic waste at the landfill.

In addition, the new fuel also produces 34 percent less soot. Soot plays an important role in the formation of contrails and, in addition to the carbon emitted by the engines, contributes to global warming.

Numbers like this could make airlines that are actually looking to reduce their carbon footprint optimistic. Commercial airlines' global fuel consumption has increased every year since 2009, reaching an all-time high of 96 billion gallons in 2019. And despite a dip in growth in 2020 and 2021 due to the corona pandemic, consumption is expected to rise again as soon as international travel is fully resumed. In the meantime, the industry has at least committed to reducing carbon emissions by 2050. Although with battery-powered aircraft is being experimented with, many airlines are skeptical about their effectiveness for larger long-haul flights. Creating new fuels that will work on existing aircraft is therefore considered by many to be the most viable alternative approach.

The effects of food waste

Around a third of the food produced worldwide is wasted. With food, not only do precious resources end up in the garbage, which turns into large amounts of organic waste, but it also wastes resources that are needed for the cultivation, storage and transportation of food. And if you let this wet bio-waste rot, it creates methane, a greenhouse gas that is more harmful than carbon. Food waste is thought to contribute around 8-10 percent of the gases responsible for man-made climate change.

In addition to all this waste, the methane produced could be used for other purposes. So it is to be hoped that biowaste will be put to a more practical and sustainable use in the future.

Of course, the development of new jet fuels is not the only solution to the negative climatic effects of flying and these attempts can also be called greenwashing, as it does not really address the fundamental problems. Of course, the most effective way to reduce carbon emissions is with frequent fliers simply flying less. Although transcontinental travel still requires flights, many more sustainable alternatives for domestic travel could be developed, promoted and made more affordable - including pre-existing ground transportation such as rail. The money could come from the long overdue taxation of aviation kerosene.

The University of California is currently planning to expand production of the fuel and is hoping it can be tested by Southwest Airlines in 2023.

This article is a translation by Sarah-Indra Jungblut and the original first appeared on our English-language website.