Biofuels are meant to clean up flying’s carbon crisis – they won’t

Image credit: United Airlines

More wreck-o than eco? Here we find that ‘biodiesel from food crops emits an average of 1.8 times as much CO2 as fossil fuels which increases to three times more in case of biodiesel from palm oil.’ Looks like another non-solution to the claimed problem.

The UK’s aviation industry is touting biofuels as a way to make plane transport greener. But some biofuels can end up doing more harm than good, says Wired.

In the next 30 years, the number of flights is expected to increase by 70 per cent.

Unless things change, by 2050 the aviation industry will have used up more than a quarter of all the carbon dioxide we can safely emit while keeping global warming to under 1.5 degrees Celsius.

But the aviation industry says it has a way out.

Sustainable Aviation, a UK coalition of airlines, airports and manufacturers announced earlier this month that the sector plans to reach net zero emissions by 2050. Its plan? Biofuels.

The group claims that switching to biofuels will reduce the amount of carbon dioxide planes put into the atmosphere by at least 30 per cent in 2050. But they might not be the carbon solution the aviation industry is in need of.

Unless they’re used in the right way, biofuels could be a bigger source of carbon than expected, and won’t help reduce emissions at all.

Biofuel is an umbrella term for any fuel manufactured from organic material – an alternative to fossil fuels like oil, gas and coal which are formed by geological processes over long periods of time. They can be made from crops, wood or waste material which is turned into biodiesel and bioethanol.

Although burning biofuels releases carbon into the atmosphere – the same as burning any fuel – the supposed benefit of biofuels comes from the fact that that carbon released was absorbed by the organic matter as it grew.

In theory, this means that carbon simply cycles between plants and the atmosphere, rather than being released into the atmosphere after staying locked deep underground for millions of years.

At the moment Bergen, Brisbane, Los Angeles, Oslo and Stockholm airports provide a 50/50 mix of biofuel and jet fuel. Conventional fuels make the seal in the engines of older planes swell slightly which prevents leakage, so this mix is the minimum amount of fossil fuel that can be safely handled by all planes.

Representatives from the International Air Transport Association (IATA) say that manufacturers are starting to use a synthetic rubber substitute in the engines of new planes that isn’t affected by biofuels, so over time they expect the percentage of biofuel used in the mix to go up.

But just because biofuels are made from plants, it doesn’t mean they’re carbon neutral.

Although direct emissions from biofuel are lower than fossil fuels – burning enough biofuel to generate one megajoule of energy gives off the equivalent of 39g of CO2, whereas for fossil fuels that figure is 75.1g. But when you add in the carbon cost of growing and transporting biofuels, things become a lot more complicated.

“You can’t just say this is a biofuel, therefore it is five times better or tens times better,” says Chris Chuck, a professor of chemical engineering at the University of Bath. “But they know that that consumers want to hear that.”

It all depends on how far you delve into the carbon cost of biofuel: how it is made and transported, and where the materials used come from. When this is taken into account, biodiesel from food crops emits an average of 1.8 times as much CO2 as fossil fuels which increases to three times more in case of biodiesel from palm oil.

In 2017, a group of 177 Dutch scientists signed an open letter to the government to stop biofuels made from food crops being included in the EU’s sustainable development agenda, calling it a “false solution”.

And growing crops for biofuels adds another problem to the mix: it requires vast tracts of land.

Full article here.