Cleaner vehicles, better cooling systems at terminals and installing solar panels in open spaces around Changi Airport's runways.
These are among the propo-sals mooted by an international panel of experts and business representatives to reduce the carbon footprint of Singapore's aviation sector.
In a report it submitted to the Government on Friday, the 20-member panel gave 15 recommendations on how to make the airport, airlines and air traffic management here greener.
The Government will study its proposals and incorporate them into a blueprint that outlines Singapore's 2030 and 2050 goals for a greener air hub. This will be published in 2023.
The report comes as the global aviation industry moves to address climate change, which the panel said is "an existential issue that impacts air travel directly".
It is untenable for the industry to remain on its current trajectory, the panel said, noting that the sector's contribution to global emissions is estimated to increase from 2 per cent before the pandemic to 22 per cent if nothing is done.
Transport Minister S. Iswaran said on Friday that the report and the upcoming blueprint are clear signals of Singapore's commitment to sustainability, which in turn will give Changi an edge over other air hubs.
The panel, formed in February, proposed six ways that Changi Airport can reduce its footprint.
One is to replace the existing fleet of about 2,000 to 3,000 vehicles used for airside operations with cleaner alternatives, such as fully electric or hydrogen-powered vehicles. About 10 per cent of Changi Airport's airside vehicles are already fully electric.
For larger vehicles that are harder to convert, such as catering trucks, the panel mooted using renewable diesel made from animal fats, food waste and plant oils.
The panel also found that air-conditioning consumes the most electricity at Changi Airport, accounting for 60 per cent of the power used by the four terminals.
It said solutions such as district cooling can be adopted to make air-conditioning at the airport more efficient. Detailed assessments should be done over the next two years, including trials.
These alternative cooling methods can then be included in the design of the upcoming Terminal 5.
Changi should also look at whether it can install solar panels on untapped open spaces within the airfield to meet an additional 5 per cent of its energy needs. The airport's rooftop panels currently generate about 4 per cent of its energy use pre-Covid-19.
The Civil Aviation Authority of Singapore (CAAS) should conduct a technical assessment to consider issues such as safety and commercial viability, the panel said.
CAAS should also try to secure imported low-carbon electricity for the airport, and a study should be done to see if it is feasible to establish a facility that can convert waste material into fuel or electricity, the panel said.
On the air traffic management front, the panel said new technology and operating procedures can help to reduce unnecessary fuel burn and emissions by facilitating more direct flight routes, among other things. These improvements could also benefit passengers by minimising delays.
The panel gave three recommendations that it said could be implemented within the next four years, and a fourth that could come into play some time from 2027 to 2032.
The proposals include studies on ways to improve the reliability and timeliness of weather information provided to pilots and air traffic controllers.
For airlines, the panel gave five recommendations centred on promoting the adoption of sustainable aviation fuel and new aircraft technology.
One is the need for Changi to develop a long-term secured supply ecosystem for sustainable aviation fuel, which has been touted as the most promising near-term solution to significantly reduce carbon emissions from planes.
It is produced from renewable raw materials, such as used cooking oil or animal fats, but costs three to five times more than conventional jet fuel.
Since July, Singapore Airlines and Scoot flights out of Changi Airport have started using a blend of regular jet fuel and sustainable aviation fuel in a one-year trial.
While the panel said its 15 recommendations will allow Singapore to distinguish itself from other air hubs, it also flagged the potentially higher costs.
As an early adopter, the Republic will need to be wary about compromising the air hub's competitiveness, the panel said. For instance, high sustainable aviation fuel premiums could distort pricing and result in an uneven playing field.
Asked about this, Mr Iswaran said: "Various air hubs around the world will seek to differentiate themselves, and those who are able to implement effectively a sustainability programme are the ones that will really command greater attention."
Travellers will be closely scrutinising what different air hubs and airlines are doing, so even if it means slightly higher costs, "it will also have an important competitive dividend payout", he said at an event.