Optimised flight networks will reduce aviation emissions
The aviation sector is taking action to reduce emissions and mitigate its impact on the environment. In 2022 for example, the 193 countries that make up the International Civil Aviation Organization (ICAO) adopted a long-term global aspirational goal of net zero carbon emissions from international aviation by 2050. In order to meet this goal, four key pillars of aviation must be addressed. These include: better aircraft technology; development of sustainable fuels; operational and infrastructural improvements, and implementation of market-based measures such as carbon offsets and emissions trading.
Restructuring global flight connections
The EU-funded REIVON project focused on a category of operational improvements that had been given little attention so far – the restructuring of global flight connections. “The first element we looked at here was the fuel savings potential of intermediate stops for long-haul flights,” says REIVON project coordinator Thomas Roetger from Envisa in France. “A direct long-haul flight from Europe to South-East Asia will have to carry and burn a lot of fuel, just to carry the fuel necessary for the second half of the flight.” An intermediate stop somewhere could mean a significant decrease in the amount of fuel that is needed to be carried, resulting in smaller tanks and, thus, lighter aircraft. With such optimised aircraft, significant fuel savings could be obtained despite the fuel burn for the second take-off. A second element that the project team looked at was frequency reduction on busy routes. Roetger notes that while high-speed trains could replace a number of short-haul routes in Europe, many highly frequented domestic flight routes around the world would be difficult to cover by any other mode of transport. The project team wanted to know whether it could be more fuel-efficient to reduce the frequency of such flights – from every half hour to every one or two hours, say – but use larger aircraft to ensure that passenger traffic is unaffected.
Fuel savings at the global level
The project developed theoretical models to determine if such operational changes could result in significant fuel savings, and thus cost and environmental benefits. Roetger and his team then attempted to quantify total fuel savings at the global level. “We came up with a 10-20 % saving in global fuel consumption when considering the use of rightly dimensioned aircraft, including aircraft with size/range combinations that do not exist today,” adds Roetger. “The CO2 saving potential identified in REIVON is highly compelling, and comparable to the cumulative impact of all other operational measures aimed at emissions reduction.”
Harmonised global flight operations
Roetger points out that these figures are purely theoretical, and that practical constraints need to be taken into account. These include geopolitical considerations (such as landing in countries at war), a lack of suitable intermediate stops in regions such as the Pacific, and passenger acceptability of intermediate stops and less frequent scheduling on some short-haul routes. “Having an intermediate stop means that the journey would take longer door to door, and reducing frequency on busier routes could impact passengers, for example when having to catch a connecting flight,” he explains. “All these points now need to be investigated in more depth.” Ultimately, the project has helped to underline that a fuel-optimised flight network, along with size- and range-optimised aircraft, can make a significant contribution to reducing aviation emissions, alongside new aircraft and fuel technologies.
Keywords
REIVON, aviation, emissions, ICAO, carbon, fuel, CO2
