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Aviation emissions statistics -

It is no great secret that flying is bad for the environment. In 2022, the aviation industry was responsible for 2% of global greenhouse gas emissions.

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The problem statement -

With the ambitious world aim of limiting global warming to 1.5°C by 2050, there is a lot of work going into finding a solution to the aviation industry emissions problem.

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Ready, set, go! -

The use of fossil fuels to power aircraft is simply no longer viable, so the race is on to find the best alternative fuel.

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Various options -

There are, of course, other options. It’s not all about traditional jet fuels. Indeed, there are both small electric planes and even a few solar powered planes that have shown promise.

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General consensus -

The general consensus, however, is that these solutions will not scale and that at least for now we are in need of a jet fuel that doesn’t pump carbon into the atmosphere.

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Sea kelp -

One potential fuel source that is generating a lot of buzz is sea kelp. Sea kelp is a form of seaweed that grows fast and is great at extracting CO2 from the air during photosynthesis.

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Carbon sequestration -

When kelp branches break away from their roots and sink to the ocean floor, they take that CO2 with them. The CO2 then stays on the ocean floor, rather than in the atmosphere.

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Number crunch -

According to one BBC article, macroalgaes such as kelp and seagrass remove around 61-268 million tonnes (23-295 million tons) of carbon from the atmosphere each year.

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Kelp as a fuel -

It is perfectly possible to turn kelp into a biofuel. Of course, when it is burned it will release CO2 into the atmosphere, but it will not release more than it previously removed.

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Added benefit -

In this way, burning kelp-based fuel should not produce any extra emissions. Kelp forests also come with the added benefit of providing a great habitat for other carbon-sequestering species.

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Why the buzz? -

Experts say that biofuel from kelp is so promising because not many changes to planes and airports will be required to accommodate the new fuel.

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Why the buzz? -

To quote the co-founder of California-based biofuel company Marine BioEnergy, “It in many cases looks like crude oil and it goes through the same processes.”

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Supply -

The big question, however, is how the aviation industry can get its hands on enough high-quality kelp fuel to power its many aircraft.

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More kelp, more kelp -

It is clear that large-scale kelp farming will be required, and for that to happen we need to increase the rate at which kelp currently grows.

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Current research -

Marine BioEnergy has been working with researchers at the Wrigley Institute for Environmental Studies on Santa Catalina Island, California, to come up with a solution.

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The concept -

The basic idea is that by attaching kelp to a boom that is lowered and raised in the water, the kelp will have the benefit of both the sunlight at the surface and the nutrients in the deep water.

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Depth-cycling works -

Experiments have shown that this “depth-cycling” helps kelp grow at a faster rate, and experts believe that it provides an exciting possibility for biofuel generation.

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In practice -

Certain players in the aviation industry have already expressed an interest in algae-based fuel as an alternative fuel option.

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Airbus and algae -

Airbus fueled an aircraft with algae biofuel as far back as 2010, and the aviation giant is now working with researchers to find out how best to grow it.

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Microalgae project -

One project that enjoys Airbus collaboration is led by Thomas Brück, a professor of synthetic biotechnology at the AlgaeTec Center in Munich, Germany.

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Microalgae project -

Brück and his team have identified a microalgae that grows quickly in diverse conditions, and they are working to increase its tolerance to salty conditions using genetic engineering.

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Showing promise -

This would mean that the microalgae could grow in conditions too inhospitable for other species, thus increasing the potential growth and harvesting rate.

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Verbatim -

Brück is quoted as saying, “We can provide between 40-50% of aviation fuel in seven years if we start today.”

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The caveat -

One major disadvantage with respect to kelp, however, is that this microalgae approach will require new refineries and distribution systems, which is of course very expensive.

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Other options -

Moving away from algae-based fuels, another suggested solution to the aviation fuel problem is household waste. This forms the focus of a research group at the University College of London (UCL).

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Household waste -

According to the chemical engineer who is leading the team, jet fuels made from waste could be in use by 2025.

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Hydrogen fuels -

There is also interest in hydrogen-based fuels, which are less similar to fuels currently in use and so would be a further move away from the status quo.

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Hydrogen fuels -

Airbus is currently working on three hydrogen-powered aircraft that it hopes will be up and running by 2035.

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Reality check -

Just like with electric planes, however, it seems unlikely that hydrogen planes will be able to carry large numbers of passengers over long distances.

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All in all -

When it comes to deciding on the best solution to the aviation problem, the jury is still out. It seems like we will need a combination of these technologies if we hope to tackle the issue.

Sources: (BBC) (The Engineer)

See also: Can underwater farms save the world from climate change?

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