Pathways to zero-carbon aviation

Faculty of Environment researchers are uncovering key insights to help decarbonise aviation, bringing their expertise to industry and government.

Their research includes analysis of emissions, alternative fuels such as hydrogen, technology, and consumer behaviour.

As well as carbon dioxide (CO2) emissions, the research also considers other aviation climate impacts such as contrails, nitrogen oxides, soot, and sulphur aerosols.

Flying with alternative fuels

Dr Alex Rap and his group from the School of Earth and Environment research the impacts of non-CO2 aviation emissions, including those from condensation trails (contrails) produced by aeroplanes in the sky. Their work focuses on developing climate models that can provide robust estimates of these impacts.

He has worked with the UK Government and the Aerospace Technology Institute (ATI) to contribute to their understanding of non-CO2 impacts of aviation.

Dr Rap led the University of Leeds contribution to FlyZero - Climate impact of emissions from aircrafts using alternative fuel and energy systems, with co-investigators Professor Piers Forster, Professor Martyn Chipperfield, Professor Benjamin Murray, Dr Wuhu Feng, and Dr Ailish Graham.

To advise the UK’s strategy to lead in this area, the programme explored options for zero-carbon emission commercial aircraft.

Researchers evaluated the climate impact of emissions from different fuels, including sustainable aviation fuel (SAF), hydrogen combustion, fuel cells (hydrogen), and battery electric.

Their work contributed to the ATI’s reports about sustainable aviation and future fuels, which focused on the impact of water and other non-CO2 emissions from different energy sources.

The results showed that while hydrogen combustion and fuel cell powered aircraft would produce more contrails, these contrails would dissipate more quickly and would have a smaller climate impact than those produced by kerosene-fuelled aircraft.

Overall, the report found that green liquid hydrogen is the most viable zero-carbon emission fuel and could be scaled up to larger aircraft.

It was presented to government ministers to inform policy, helping to mitigate climate change impacts through alternative fuels, flight traffic management, and more.

Predicting aviation’s climate impact

Institute for Climate and Atmospheric Science (ICAS) researchers continue to work towards a better understanding of alternative fuels and sustainable aviation technologies.

Dr Rap is currently leading the MAGICA – Modelling Aviation Global climate Impacts from Contrails and Aerosols project, which aims to develop and use climate models to quantify global aviation climate impacts from contrail cirrus and aerosol-cloud interactions.

The co-investigators on this project are Professor Ken Carslaw, Dr Feng, Professor Paul Field, Professor Forster, and Professor Murray.

Working with the UK Met Office, University College London (UCL) and several industry partners such as Airbus, Aviation Environment Federation (AEF), British Airways (BA), International Air Transport Association (IATA), Jet2, and Rolls Royce, MAGICA will guide the sector’s future technology by informing industry and policymakers.

Dr Rap, Professor Forster and Professor Amanda Maycock also work with the University of Southampton, Airbus and Rolls Royce on the project ‘Contrail Assessment of Future Aircraft and Propulsion Architectures.’

They investigate the contrail climate impact of future low-CO2 aircraft, including its interactions with climate-optimised aircraft design.

Collaborating with the industry partners means this project will directly impact the future of sustainable aviation.

TOZCA – Towards Zero Carbon Aviation is a project which develops tools to simulate the transition to net zero-carbon aviation by 2050 and 2070. It particularly looks at the cost associated with the possible pathways.

It will investigate the consequences of CO2 reduction through changes to technology, fuel, operations, and consumer behaviour.

Dr Rap, Professor Charisma Choudhury and Professor Forster lead on the models for air passenger behaviour and the non-CO2 climate impact of aviation.

Many aircraft manufacturers are working with the research team on the project, as well as the Department for Business, Energy & Industrial Strategy, Department for Transport and the Aviation Environment Federation.

Aviation is one of the largest sources of greenhouse gas emissions in the UK.

The Faculty of Environment researchers and projects will contribute to the UK Government’s Jet Zero Strategy, which aims to decarbonise the aviation sector by 2050.