The Current state of airplane fuel
Modern planes currently run on a Jet A-1 type aviation fuel called kerosene, a meticulously refined and light petroleum. This fuel is used over options such as gasoline due to its lower freezing point and viscosity, as well as its higher flash point that helps achieve greater power and efficiency. However, although efficient, burning kerosene produces pollutants such as carbon dioxide, nitric oxide, nitrogen oxide, and sulfur oxides. In fact, commercial aviation contributed to 2.8% of global Co2 emissions in 2019 from the use of this fossil fuel. Although a seemingly small amount, one study stated that if the rapid growth in plane emissions continues, by 2050 aviation could account for 25% of the worlds “carbon budget”, or the amount of carbon dioxide emissions permitted to keep global temperature rise to within 1.5 degrees Celsius above pre industrial levels.
A possible solution?
According to some planemarkers, hydrogen is a possible solution to the urgent crisis of carbon emissions. Hydrogen is a sustainable fuel that does not produce harmful emissions and is beginning to be tested as a possible replacement for kerosene in aviation. Hydrogen fueled aircrafts would emit only water and some tests claim them to be just as efficient as traditional aircrafts. Smaller planes would likely utilize propellers with hydrogen-powered fuel cells, while larger planes would likely burn hydrogen to power jet engines. However, there are still many obstacles to overcome for this idea to become a reality. For instance, the enormous energy costs of making hydrogen as well as its deficiencies in energy density compared to kerosene. Researchers found it would require fuel tanks four times the size of current tanks due to liquid hydrogen carrying about four times the volume for the same amount of energy of kerosene. To overcome these obstacles there will need to be advancements in hydrogen storage technologies as well as redesigns of airplanes to incorporate the necessary systems and tanks to run planes on hydrogen. However, progress is already being made in these fields and according to Dr Bart Biebuyck, executive director of the Fuel Cells and Hydrogen Joint Undertaking, it should be possible to run a short range flight plane on hydrogen by 2035.
Real attempts
Many hydrogen powered planes have been attempted with some successful attempts proving the technology possible. In 2008, Boeing successfully flew the world’s first hydrogen powered plane at an airfield south of Madrid, Spain. A two seat aircraft was modified to use hydrogen fuel cells to power an electric motor, coupled to a conventional propeller. The plane was able to reach 3,300 feet in the air and fly straight and level at 62 miles per hour for 20 minutes. Since then even more progress has been made with the first four seater hydrogen plane successfully flying in 2016 at the Stuttgart airport in Germany. This aircraft was developed primarily by Germany’s DLR Institute of Engineering Thermodynamics and features a lithium battery that covers peak power loads during take-off and ascent, as well as a low-temperature hydrogen fuel cell that converts hydrogen directly into electrical energy. Even more recently, the first hydrogen fueled, commercial size aircraft had its first successful flight. In September of 2020 a 15 minute, 20 mile flight took place at Cranfield Airport in England and made history. It was built by ZeroAvia and used liquid hydrogen to feed fuel cells. Progress like this is huge for the future of aviation as hydrogen continues to prove itself as a possible fuel replacement for kerosene.
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