Guilt-free flying – fantasy or reality?

Aryan – Year 11 Student

In the last few decades, the evolution of aircraft has been phenomenal. It wasn’t too long ago that humanity witnessed the birth of flight thanks to the Wright Brothers. Now we find ourselves in a position to fly to Mars. We have conquered our desire to fly, persevered in becoming a species willing to dominate the world, but perhaps most importantly, we have made air travel an affordable experience for all. But has our technology evolved in accordance with our desire? Have we mastered the balance between the environment and the economy, or are we now starting to pay the price for our laziness?

Recently, the importance of climate change has caused scientists to look for more environmentally friendly alternatives to our everyday lives. Transport has become a crucial part of many people’s lives; however, now more than ever do we realise how detrimental it is to our wellbeing. The emissions from the fossil fuels that we are using for this travel are slowly building up and overwhelming us. Whilst we perhaps cannot completely change our lifestyles, we can change the fuel for our vehicles.

Hydrogen is the most common element in the universe, but this is not very helpful for scientists given that it is usually found in compounds such water and methane. However, thankfully, scientists have developed a method, called electrolysis, to separate hydrogen from a molecule. This process runs a current into graphite electrodes in order to separate the components of an ionic compound. Another method is to react carbon monoxide with steam; this is called a water-gas shift reaction. But how can any of this be used to create fuel?

For many years, scientists have tried to use hydrogen as a fuel for cars and planes; not only is it abundant, making it cheap, but it also much more beneficial for the environment than fossil fuels. One of the many problems with hydrogen fuel is that hydrogen must be in a liquid state. Therefore, the gas must be compressed using high-pressure gas cylinders, but this prolonged process causes the liquid hydrogen to lose up to 40% of its specific energy capacity, which defeats the goal of energy efficiency. Furthermore, storing liquid hydrogen requires conditions just above absolute zero, a theoretically and experimentally impossible limit to reach since we cannot remove every bit of heat from the universe. So is it worth it?

Liquid hydrogen fuel carries one hundred times as much energy per kilogram than kerosene, the current aeroplane fuel, whist simultaneously carrying more than twice as much energy per unit mass than gasoline, the centre of human transport.

Thankfully, progress in this area of science is moving in the right direction. Recently blueShift, an aerospace company, launched the first ever biofuel run rocket into space. Furthermore, ZeroAvia has recently sent a hydrogen-fuelled plane on a nineteen-mile journey around Cranfield airport. In addition, scientists have created a fuel cell that can store liquid hydrogen for up to five hours. If this liquid hydrogen project is a success then it can be used as rocket fuel and commercial airline fuel; however, at the moment, I feel that we are far away from this feat, but I will leave the decision up to you.

References

https://www.tandfonline.com/doi/full/10.1080/15435075.2019.1685999

https://www.shell.com/energy-and-innovation/new-energies/hydrogen.html

https://www.economist.com/science-and-technology/2020/12/08/is-the-time-now-ripe-for-planes-to-run-on-hydrogen

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