A Strategy to Decarbonize Civil Aviation: A phased innovation approach to hydrogen technologies

Greening aviation is key to our global future. However, reducing aircraft operations would severely impact worldwide economics. Therefore, it is imperative that radical and green propulsion alternatives be developed quickly. The most likely approaches to succeed in this grand challenge are hydrogen (H
₂
) and electrification, which hold the promise of complete decarbonization. H
₂
is a promising solution for a fully sustainable aviation future, via hybrid/fuel cell technologies for short-to-medium-range and direct H
₂
combustion in turbine engines for longer missions. However, the huge financial investments required to make this a reality will not be considered until several technical challenges can be overcome. Given the pressure to start decarbonizing soon, we propose a philosophy of innovation waves on the basis that to accelerate the implementation of the necessary technologies, it would be beneficial to rapidly develop suboptimal solutions and improve them through time and experience.