Could the world be on the brink of a new, cleaner era of aviation? That’s certainly what you might think from the way some people are talking.
Mandates for blending so-called Sustainable Aviation Fuel into jet kerosene form one plank of the European Union’s recently announced plans to reduce emissions 55% by 2030.
The technology will be key to airlines’ ambitions to get to net zero by mid-century, according to a study by the World Economic Forum. Airbus SE has released dazzling concept designs for three zero-emission aircraft, and plans to devote five years to studying the idea before deciding whether to spend money developing a commercial version.
The feeling of progress toward eliminating air travel’s carbon footprint is no doubt valuable to the sorts of affluent, globally aware customers on whom the industry depends. There’s a reason airlines were some of the earliest and most important sellers of carbon offsets to consumers — though the environmental benefits from such products are often patchy at best.
Unfortunately, the truth is that mitigating emissions from aircraft is one of the most challenging areas the world will face over the coming decades. In power generation, road transport, steel, chemicals and shipping, there are genuine breakthrough technologies such as wind, solar, batteries and green hydrogen which could sharply reduce or even eliminate carbon. Aviation’s best alternative technologies are far more incremental, and each have substantial barriers to adoption.
Take Sustainable Aviation Fuel, or SAF. The vegetable oils that we use in cooking and cosmetics are chemically not all that different from the hydrocarbon chains derived from petroleum. Blending a mix of up to 50% biofuel into an aircraft’s tanks doesn’t even normally require any change in the basic technology. SAFs already comprise about 0.1% of the jet fuel market, and data providers S&P Global Platts and Argus Media last year started publishing regular prices.
However, it’s hard to see how SAFs will more than nibble at the edges of the aviation industry’s emissions. For one thing, they’re four or five times more expensive, and fuel already comprises about a quarter of airlines’ costs. That’s quite different from renewables and electric vehicles, which are at or below
cost parity with conventional alternatives.
Supply is a further problem. The world’s agricultural land is struggling to meet burgeoning demand for household fats as it is, with palm oil prices rising to a record of 4,506 Malaysian ringgit ($1,066) per metric ton in May. To meet half of 2019’s 300 million tons of jet fuel demand with palm (by far the cheapest as well as most productive commercial vegetable oil, in terms of tons per hectare) would require nearly three times the present area planted for large-scale cultivation.
It’ll be even harder in the future: Aviation fuel demand is likely to rise threefold by 2050. Finally, there’s the question of how much carbon such measures really mitigate.