Opinion
Clean aviation will take more than just biofuels
Summary
As prime mover of the Global Biofuel Alliance, India hopes to become a major supplier of sustainable aviation fuel. Whether bio-blends can clean up the sector, though, is unclearUnion minister Hardeep Singh Puri recently said that the Global Biofuel Alliance (GBA) could turn India into a major producer and exporter of sustainable aviation fuel (SAF). He was referring to a class of biofuels that could potentially reduce the climate-harming gas emissions of aircraft by up to 80%, as widely touted. With jet engines burning fossil fuels, aviation accounted for 2% of all carbon exhaust in 2022, a slice that will widen rapidly unless this sector finds a way to decarbonize. Electric planes of jetliner size remain a challenge of technology. They would need very light-weight batteries. As take-offs demand enormous thrust, an airframe design that can get airborne on electric power remains a steep ask. Until key breakthroughs are made, there will be no estimated-time-of-arrival for clean air travel. Hence, the industry’s best bet right now for carbon neutrality is the adoption of SAFs (combined with carbon capture). This is a transition that the GBA aims to accelerate.
The SAF-led path to carbon neutrality, however, is unlikely to be smooth, strewn as it will be with various possible air pockets. Consider SAF supply capacity. Biofuels typically require vast quantities of agricultural produce. Ethanol yielding crops like sugarcane and corn are used for it and their acreage has been increasing across the world. Yet, as it involves a diversion of farm resources away from primary purposes like nutrition, output constraints will kick in sooner than we’d like. Thankfully, other kinds of biomass can be used too. The government has indicated that India’s SAF plans are based on making use of bio-waste—like used cooking oil, forest residue and agricultural and municipal refuse—apart from non-food crops. Even so, feedstock sufficiency will be hard fought. The idea is to start with a blend of very little biofuel—say 1%—mixed with regular jet fuel, and then gradually raise the bio-content as SAF-adapted aircraft come along. According to Puri, even if a 50% mix comes into use by 2030, our domestic needs would be less than half of what the country could make. If so, it would be impressive, but that’s a big ‘if,’ given what all it will take. Right now, SAFs make up barely 0.1% of global aviation fuel consumption. Their long and complex production process makes them far costlier than jet fuel and their low energy density means larger volumes are needed to refuel planes. As with batteries, this is a burden.
Clearly, SAF conversion will require a heavy regulatory push. Globally, this has begun as carbon offsets slowly come into play under the Carbon Offsetting and Reduction Scheme for International Aviation laid down by the UN’s apex body for this sector. Foreign flights run by Indian airlines will have to comply with those norms within half a decade. To this end, we have made a small start. On 19 May, we celebrated a Pune-Delhi AIX Connect flight that used a 1% SAF blend produced locally. This is the direction in which Indian air carriers will be prodded as soon as we have enough of the stuff. The real test of SAFs, however, will come once carbon trading—in a market where companies buy and sell the ‘right to pollute’—assumes significance, wider track records emerge, and all claims are put to rigorous scrutiny. Sceptics abound of their emission-cutting claim of 80% even in a best-case scenario. Whether an SAF shift will actually help clean up aviation won’t be known for many years. The innovations we’ll eventually need might have to focus on aeroplanes more than what goes into fuel tanks.
