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The fat from dead pigs, cattle and chickens is used to make greener jet fuel, but a new study warns it will ultimately be worse for the planet.
Animal fats are considered waste, so jet fuel made from the material has a much lower carbon footprint.
Demand for fuel made from animal by-products is expected to triple by 2030, with airlines leading the way.
But experts fear that scarcity will force other industries to use more palm oil – a huge generator of carbon emissions.
Airlines are under pressure to rein in their massive CO2 emissions, which mainly come from the combustion of fossil kerosene in jet engines.
But the study by Brussels-based Transport & Environment, a clean transport campaign group, suggests that there are simply not enough animals being slaughtered each year to meet the growing demand from airlines for animal fats.
“There is no infinite supply of animals or animal fat,” said Matt Finch of Transport & Environment.
“So if you have a huge additional source of demand from aviation, in this case, the industries where fat is currently used, will have to look for alternatives. And that alternative is palm oil. So indirectly, aviation will be responsible for increasing the amount of palm oil passed through the European systems.”
The increased use of palm oil is linked to rising emissions as older forests that store massive amounts of carbon are cleared for new plantations.
That animal fats are used as fuel will come as a surprise to many.
For centuries, tallow and lard have been used to make candles, soaps and cosmetics.
However, over the past 20 years, the use of biodiesel, made from this animal waste or from used cooking oil, has steadily increased in the UK and beyond.
Across Europe, the amount of fuel made from dead animals has increased fortyfold since 2006, according to the new research.
Much of this material is used in cars and trucks as biodiesel, which is classified as a renewable fuel and as such has a much lower environmental footprint under the regulations.
But UK and EU governments are now keen to increase the use of this type of waste to make aviation greener.
To that end, they are introducing challenging mandates requiring airlines to use a higher proportion of sustainable aviation fuel (SAF) in their tanks.
For the UK it will be 10% by 2030, for the EU 6% – but observers say these plans could put pressure on the current animal waste market.
There are major differences in approach between the UK and the EU. The UK is likely to limit the use of better quality tallow in fuel – while in Europe the use of this type of material will be encouraged as the greenhouse gas reduction achieved with this fat is greater.
With demand rising, prices will rise and this is likely to boost exports from the UK, which will have an impact.
How many dead pig
s do you need to fuel a plane?
According to Transport & Environment, a flight from Paris to New York would require the fat of 8,800 dead pigs if all fuel came from animal sources.
With the UK likely to restrict the use of animal products and used cooking oil, flights refueling across Britain are likely to have only small amounts of animal material in their engines.
In the EU, airlines have a target of 6% sustainable jet fuel by 2030, of which 1.2% should come from e-kerosene. Assuming that the remaining 4.8% comes entirely from animal fat, about 400 pigs would be needed per transatlantic flight.
Among the industries that may need to source other ingredients as airlines consume a higher proportion of animal fat are pet food manufacturers.
They currently use a significant amount of better quality animal by-products to feed the UK’s 38 million pets.
“These are really valuable ingredients for us and they’re hard to replace, and they’re already being put to good use in a very sustainable way,” said Nicole Paley, deputy director of UK Pet Food, the manufacturers’ trade association.
“So actually diverting these ingredients to biofuels actually creates another problem. It would put us in competition with the airline industry. And when it comes to the airline industry’s pocketbook, the pet food industry would find it very difficult to compete.”
While the EU is further along this path, the UK is currently discussing limiting the type of animal fats used in jet fuel. The government is considering a ban or strict limitation of both animal fats and used cooking oil in the aviation sector, concerned about the unintended consequences.
Many in the biofuel industry are concerned that the proposed changes could also divert animal fats from one mode of transport to another.
“If you give a big push to the use of these lipids, animal fats and used cooking oils in aviation, it will inevitably take it away from other things,” says Dickon Posnett of Argent Energy, a waste-based biodiesel producer in the UK and Europe. .
“So if you want to increase aviation sustainability at the expense of truck sustainability, go ahead. But that’s a decision for the government to make.”
