ROBIN MILLS/ Arab News:

An airliner over Dubai’s coast, a single-engine helicopter and a Japan-Abu Dhabi flight: sustainable aviation fuel, known as SAF, has proven capable of powering air travel. But can supply rise and costs fall fast enough to make SAF a major part of the aviation industry’s journey to net-zero emissions? While aviation is responsible for about 2 percent of global greenhouse gas emissions, a small but fast-growing amount, it could be two to four times higher by 2050. Its impact on global warming is higher, about 3.5 percent, because of the formation of high-altitude condensation trails — or contrails — which trap heat. Environmentalists have proposed avoiding air travel in favor of high-speed rail. This has a place, but with demand for flights likely to rise, low-carbon options are needed. The Middle East must take curbs on aviation emissions particularly seriously. It has become a global flight hub, with several regional countries — notably the UAE but also Qatar, Saudi Arabia and Turkey — betting big on economic diversity through mega-airports, super-connector airlines and spinoffs, from tourism to cargo. That will not work if future air travel is restricted. The International Air Transport Association resolved in October 2021 that members would reach net-zero carbon emissions by 2050. Its strategy includes improved efficiency, new hydrogen- and battery-powered planes and offsets, such as funding tree planting or the direct removal of atmospheric carbon dioxide. Low-carbon aviation fuel carefully selects the origin and refining of crude oil to reduce life cycle emissions by at least 10 percent.
But the heavy lifting — 65 percent of total reductions — hinges on SAF. Planes today overwhelmingly run on kerosene made from petroleum. By contrast, SAF is derived from non-fossil sources, either leftovers, such as cooking fat, other biomass or waste materials, or custom-grown feedstocks including sugar, alcohols and palm oil.
Carbon taken up by these biological materials as they grow is released when the fuel is burned, making it carbon-neutral in principle. With some development, these will yield an 80 percent reduction in life cycle emissions. Research also suggests that SAF reduces contrails. SAF is a drop-in fuel, meaning it can be used in conventional jet engines without modification, blended with kerosene or on its own. In October, Etihad flew from Tokyo’s Narita International Airport to Abu Dhabi using a 40 percent SAF blend. In January, Emirates made the first demonstration flight in the MENA region with one of two Boeing 777 engines running entirely on SAF. In February, the US aerospace company Bell Textron made the first single-engine helicopter flight using only SAF. Worldwide production of SAF tripled in 2022, but the total estimate of between 300 million and 450 million liters is far short of the 2050 annual target of 449 billion liters. That is equivalent to nearly 8 million barrels per day of oil and almost a thousand times current output.