Passenger aircraft towards zero emission with hydrogen and fuel cells

Abstract

According to the EU's "Green Deal", no more net greenhouse gas emissions should be released in 2050. All modes of transportation will have to contribute to this reduction. This includes also aviation. To keep things relatively simple here, the aircraft is considered the system boundary. This is called "tank-to-wake". The options to achieve "zero emission" flight (in these boundaries) are limited. Electric flight with batteries will be limited to short range for years to come. Burning hydrogen in jet engines would be a major step forward, but is clearly no solution to achieve "zero emissions", it emits NOx and produces potentially warming contrails. Electric flight with hydrogen and fuel cells could be an option. It has neither CO2 nor NOx emissions. It releases water in liquid form, but this seems not to be critical.