Hydrogen fuel can be used in different ways to power aircraft, including through fuel cells that generate electricity for electric propulsion, or by burning it in a jet engine or internal combustion engine. Traditional wet wings cannot store hydrogen, so it needs to be stored in the fuselage or supported by the wing in dedicated tanks. Hydrogen Fuel cells are more suitable for general aviation and small commuter aircraft, as their engine efficiency is lower compared to large gas turbines. They may not be practical for single or twin-aisle airliners. The efficiency of a hydrogen-fueled aircraft depends on factors such as the larger wetted area, lower fuel weight, and added tank weight, which vary with the size of the aircraft. Hydrogen is well-suited for short-range airliners, while longer-range flights may require new aircraft designs like blended wing bodies to accommodate the necessary hydrogen storage.
- Hydrogen is considered the most promising approach for decarbonizing the aviation industry, particularly for short- and medium-range airplanes.
- Hydrogen fuel cells produce water vapor and heat as byproducts, making them a cleaner alternative to burning jet fuel, which emits carbon and particulate matter pollution.
Several companies, such as Airbus, ZeroAvia, and Universal Hydrogen, are actively engaged in the development and testing of hydrogen-powered airplanes. The objective is to address the issue of carbon emissions from aircraft, which currently account for 2.5% of global CO2 emissions. These companies have made notable advancements in this field:
- In 2020, Airbus unveiled conceptual designs for multiple hydrogen-powered planes. They have plans to conduct a test of a hydrogen engine on an A380 aircraft by 2026.
- Universal Hydrogen achieved a significant milestone by successfully completing a 15-minute test flight of a prototype aircraft equipped with a hydrogen-based powertrain. Their focus is on converting the ATR 72-600, a regional aircraft, to utilize hydrogen fuel, with deliveries scheduled to commence in 2025.
- ZeroAvia accomplished a successful test where a hydrogen-electric engine powered one of the propellers in a 19-seat aircraft. Their ultimate goal is to enable commercial flights powered solely by hydrogen fuel cells by 2025.
- Universal Hydrogen's aircraft, nicknamed "Lightning McClean," underwent a triumphant 15-minute test flight in the United States. The plane featured a hydrogen engine on its right wing and a conventional aviation fuel engine on its left wing for safety measures.
- Alaska Airlines and ZeroAvia are collaborating to retrofit a Q400 aircraft, with the intention of transforming it into the largest zero-emission aircraft in the world. The first test flight for this project is scheduled for 2024.
These recent developments signify remarkable progress in the advancement of hydrogen-powered airplanes. The commitment shown by these companies highlights the industry's dedication to mitigating carbon emissions in aviation.