Can flying ever be sustainable? | 91TV
Transcript
- Making aviation green is a huge challenge.
- Flying is such a big part of our lives
- and we have to balance that with the fact that it contributes hugely
- to global warming.
- We've left it a long time.
- We've now got a very short window within which we need to get
- emissions from this sector down to nearly zero.
- We need to be throwing everything at this problem that we can think of.
- There are two big reasons why aviation presents a unique challenge
- in terms of climate change.
- The first is that more and more people are flying,
- and the second is that flying remains almost totally dependent
- on fossil fuels.
- We haven't got green technologies available yet
- for the aviation sector.
- And that's roughly equivalent to the total emissions from the UK
- and Germany combined.
- In 2019, airlines carried around
- 4.5 billion passengers on flights,
- and we're really expecting that to grow.
- Globally, just 1% of the population,
- many of whom are frequent flyers,
- generate half of all emissions from the aviation sector.
- There is no silver bullet to get aviation
- to become green, but rather a whole set of different options,
- each with pros and cons.
- Winglets are vertical-looking extensions
- that we've added at the end of the wings.
- And what they do is to increase the efficiency of the wings.
- These winglets were inspired by birds and we are currently looking
- at much more features from bird wings and bird flights
- and incorporating them into our aircraft.
- The aviation industry is really good at making itself
- more efficient through a mixture of improving technology
- and learning to fly the aircraft more efficiently.
- If you look at history,
- we are improving the efficiency of our aircraft
- at about 2% per year.
- That is definitely very little and it cannot continue forever,
- so we definitely need to change our aircraft fuels.
- Jet engines at the moment run on fuel
- made from fossil fuels, so it's really important that we find ways
- to replace that in aircraft.
- Biofuels are a form of fuel which is made
- from plant-based materials.
- The one possible example is vegetable oil,
- which exists in very large quantities
- and can be transformed into a biofuel.
- For instance, if we were to replace the entire jet fuel used in the UK
- with biofuels, we would be using about 68% of the land
- that we currently use to grow our food.
- Another possibility is what we call e-fuels,
- which is scrubbing the carbon dioxide from the air
- and putting it through chemical processes
- that turn it back into jet fuel again.
- So it turns into a circular process where it's all going
- into the atmosphere and then coming back out again.
- One big disadvantage of e-fuels
- is that they are very expensive, not only in terms of their cost,
- but also in terms of the energy that they use.
- Hydrogen is a gas that, if you react it
- with the oxygen in the air, can release a lot of energy.
- That makes it potentially a really good aviation fuel,
- but it's not without its problems.
- For a start, we can't store it in the current designs of aeroplanes.
- Secondly, at the moment, about 95% of our hydrogen
- comes from fossil fuels.
- Hydrogen is very explosive,
- which poses serious safety considerations.
- Designing, manufacturing and licensing hydrogen-powered aircraft
- is something that is bound to take decades
- and cost in the region of tens of billions of pounds.
- Electric airplanes are still incredibly rare.
- So, I'm one of the very few people in the world who has had a chance
- to pilot an electric airplane.
- Whilst it's possible to make an electric car that works well,
- if you put those same batteries into an airplane,
- it's simply too heavy to fly.
- There's no doubt that it's going to take
- a lot of resources, particularly energy.
- It's going to cost a lot and it's going to require a huge amount
- of effort from business and from government working together,
- with the cooperation and support of the public.
- It would be great if there was one kind of
- fix-it-all solution that we could put in place for this sector.
- Unfortunately, we're going to have to do everything we can think of,
- and it's all probably going to be quite challenging.
- A lot of the technologies that we need
- for greening aviation are still some decades apart.
- They are very expensive, and the electric energy
- that would be required from a renewable source
- will also be very expensive and time-consuming to set in place.
- Alongside that, just as importantly,
- we're probably going to have to fly less.
- Because we've left it so long, there just isn't time left.
- The aircraft coming off the production line today
- will probably still be flying in 2050, which is the date
- by which we have to be at net zero emissions.
- We need to be building the kind of society in which
- there are good alternatives to flying.
- So if you choose to take holiday domestically in your own country,
- that will start to create that kind of demand that will help
- make a more sustainable future.
- Do you fly?
- I last took a flight before my daughter was born
- and she's going to be a teenager this summer.
As passenger numbers continue to grow and the impact of air travel on the climate gets worse, solutions are needed.
We take a look at some of the alternative fuels that could help aviation become sustainable and ask whether a change in fuel alone will be enough.
Read the Royal Society's report on net zero aviation:
/new-resources/projects/low-carbon-energy-programme/net-zero-aviation-fuels/
About the Royal Society
91TV is a Fellowship of many of the world's most eminent scientists and is the oldest scientific academy in continuous existence.
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