Achieving emissions-free flight in the coming decades means addressing not just carbon output but nitrogen oxides and the impact of contrails, Lars Wagner, chief operating officer and chief sustainability officer at MTU Aero Engines, said during the Farnborough International Airshow.

The manufacturer is working on a range of solutions to the sustainability challenge under its Clean Air Engine (Claire) technology agenda.

These include enhancements of the gas turbine engine based on the geared turbofan, and completely new, revolutionary propulsion concepts, such as the water-enhanced turbofan and the flying fuel cell. Sustainable aviation fuels (SAF) and hydrogen will also play a role.

Wet engine solution

“It’s really important that we do not only look at CO2, but we also need to look into NOx and we look into the contrails,” he said. “All three elements are actually driving climate change, and our wet engine is a solution because it’s addressing all three emissions.”

MTU has outlined three stages on their journey to emissions-free flight. The first stage is marked by the geared turbofan, which has been a standard component since 2016. In conjunction with SAF, it can already significantly reduce climate impact today.

In the second stage, MTU aims to realise the water-enhanced turbofan and the flying fuel cell by 2035. A hydrogen-powered GTF is also possible.

Stage three will begin in 2050 and is aimed at further improving the efficiency of all propulsion technologies and introducing the fuel cell on short- and medium-haul routes.

Pressure from governments and society to act

Wagner said: “The pressure [to reduce emissions] is big from us, from our shareholders, but also from politicians. And then we believe from the global society, because we need to work against climate warming, and air traffic is one contributor to the CO2 in the atmosphere.

“So you need to do something about it. And that’s why we are sustainable and we want to grow our business with these alternative technologies.”
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