For short journeys probably with electricity and hydrogen, for long journeys with biofuels. Everyday realities have not yet been deeply affected by the determination of most of the developed world to move to a climate-neutral, CO2-free economy in all sectors. The coronavirus epidemic has also caused us to talk less about climate-neutral industry, households and transport, even though these transformation processes are taking place all around us at an almost frightening pace. Aviation is no exception.
A recent publication by the Swiss non-profit organisation the World Economic Forum (WEF) (which organises the infamous annual Davos meeting for the most influential representatives of the business world) shows what changes we can expect to see in aviation.
The reduction of CO2 emissions from the transport sector is not following the trends set by the EU, so strong political enforcement measures are expected. The same applies to aviation, which today accounts for only 3% of global carbon emissions, but has a two to four times greater role in climate change because of its other environmental impacts. And it is not just politics that is putting pressure on the industry: there is also a growing demand for change from passengers.
Aviation is characterised by the use of high-value, long-life assets; an aircraft can last 25 years or more. In principle, some of today’s new aircraft will still be able to fly when we reach the EU’s CO2 neutrality target date of 2050. Advances in conventional technology are improving the efficiency of engines somewhat, reducing CO2 emissions by mass, but if no change is made and aviation continues to rely on kerosene, economic projections suggest that by 2050 we will not just be at zero carbon emissions, but 1.7 times last year’s pre-COVID levels.
The Clean Skies for Tomorrow initiative, launched by the WEF last year, brought together airlines, aviation operators, research institutes, NGOs and back-end industry – some 80 organisations – to radically change the technical landscape of aviation. This change includes three key priorities: the increasing use of biofuels and their production, and the development of electric and hydrogen-based aviation.
While battery-powered electric aircraft could reduce CO2 emissions by 100% (if the energy comes from renewable or nuclear sources, of course), the use of heavy batteries is only a solution for short-haul aviation at best, and of course these machines, which do not yet exist, need to be developed. Hydrogen cell aviation requires major infrastructure development and also the design and production of completely new machines with a 75-90% reduction in climate impact. These machines would also only be usable for shorter journeys. Using aircraft that burn hydrogen in a jet engine would allow long-range flights with half to three quarters of the current climate impact. And jet fuel from bio-cosine or renewable sources, while requiring minimal technical modifications and infrastructure investment, would only reduce climate impacts by 30-60% in a full switchover.
The analysis in the remaining pages of the Sustainability in Aviation report discusses the impacts and economic comparability of alternative fuels that can be burned in conventional jet engines. Although a bioethanol plant and a sugar cane plantation are technically less exciting than an aircraft, they are the more interesting topic in terms of the impact on societies. The replacement of oil products by agricultural and forestry-based raw materials is expected to create jobs for large numbers of people in vast areas, including in the developing world.
These types of fuels can be well implemented in existing aviation infrastructure, but exactly which is the future is hard to say. Production costs and the scale and return on investment required to produce them vary widely, according to the WEF report, while some regions may be better suited to producing certain fuels.
It is therefore most likely that the technical background to aviation will be more diverse than today and that not all aircraft will be fuelled with the same Jet-A or Jet-A-1 at airports. The changeover and the production of new fuels will be expensive, but the authors of the study say it would be even more expensive for humanity if it did not take into account the effects of climate change. In the long term, as with all energy-intensive activities, aviation is better off taking the sustainable route.