Keys to Decarbonisation, Part 1: Biofuels



Commercial aviation (along with much of aviation in general) has for more than a decade now been committed to “green” development, with much of the sector now dedicated to reducing polluting emissions with a goal of net zero by 2050. To put this into perspective, this sector emits less than three percent of greenhouse gases into the Earth’s atmosphere, whilst cattle raising is responsible for 19 percent; Internet servers more than two percent; and the information/communication technology sector another two percent. But with the year-to-year expansion of global air traffic, it’s been estimated that left unchecked, that less than three percent could rise to 20 by 2050.

Thus the supreme importance of this “green revolution” in flying – and one of its most critical elements is the increasing use of biocombustibles – fuels derived from plants.  In 2009, IATA (the International Air Transport Association) – whose members account for more than 90 percent of international flights – committed them to net zero carbon emissions by 2050 and two years issued standards allowing the use of of a 50-50 biofuel-kerosene mix (known as SAF, sustainable airline fuel), in commercial aircraft. To complement this, besides its emphasis on biocombustibles and SAFs the airline sector has put into service an increasing number of more efficient aircraft as well as electric vehicles at airports.

On 14 July of this year, the European Commission unveiled a package of measures it calls Fit for 55, which includes an initiative called Refuel EU Aviation, the objective of which is to stimulate the supply and demand of sustainable aircraft fuels within the European Union, reaching two percent of all fuel use by 2025, five percent by 2030, and 63 percent by 2050.

Just this past October, the 77th Annual General Assemby of IATA passed a resolution aimed at achieving zero carbon dioxide (CO₂) emissions by 2050: “a commitment by the air transportation industry in line with the objective of the Paris Accords to not surpass 1.5 degrees Celsius”.

Willie Walsh, IATA’s director general (as well as former advisor delegate of IAG, the holding company to which Iberia belongs), noted at this meeting that “the world’s airlines have taken a momentous decision to ensure that flying is sustainable. The post-COVID-19 re-connect will be on a clear path towards net zero. With the collective efforts of the entire value chain and supportive government policies, aviation will achieve net zero emissions by 2050”.

The aviation industry must progressively reduce its emissions while accommodating the growing demand of a world that is eager to fly. To be able to serve the needs of the ten billion people expected to fly in 2050, at least 1.8 gigatonnes of carbon must be abated in that year. Moreover, the net zero commitment implies that a cumulative total of 21.2 gigatonnes of carbon will be abated between now and 2050.

Walsh continued, “Achieving sustainable global connectivity cannot be accomplished on the backs of airlines alone. All parts of the aviation industry must work together within a supportive government policy framework to deliver the massive changes that are needed, including an energy transition. That is no different than what we are seeing in other industries. Road transport sustainability efforts, for example, are not being advanced by drivers building electric vehicles. Governments are providing policies and financial incentives for infrastructure providers, manufacturers and car owners to be able to collectively make the changes needed for a sustainable future. The same should apply to aviation”.

The strategy is to abate as much CO₂ as possible from in-sector solutions such as sustainable aviation fuels, new aircraft technology, more efficient operations and infrastructure, and the development of new zero-emissions energy sources such as electric and hydrogen power.

According to Walsh, “A potential scenario is that 65 percent of this will be abated through sustainable aviation fuels. We would expect new propulsion technology, such as hydrogen, to take care of another 13 percent. And efficiency improvements will account for a further three  percent. The remainder could be dealt with through carbon capture and storage (11 percent) and offsets (eight percent). The actual split, and the trajectory to get there, will depend on what solutions are the most cost-effective at any particular time. Whatever the ultimate path to net zero will be, it is absolutely true that the only way to get there will be with the value chain and governments playing their role”. Here we’re going to focus on that 65 percent Walsh mentioned in the name of this economic sector.

In 1927, Friedrich Bergius, who in 1931 would win the Nobel Prize in chemistry, began to produce synthetic petrol after 15 years of work and testing. Subsequently, various other methods were developed of creating synthetic fuels from various sources. During World War II, German forces depended to a great extent on petrol synthesised from carbon; it’s estimated that 92 percent of the fuel utilised by German planes and 50 percent of that burned by trucks and tanks was synthetic; by the start of 1944, when that production reached its high point, 25 factories produced 124,000 barrels per day – the equivalent of 159 litres (42 gallons) each.

Flash forward 50 years.

When the comercial aviation industry began working to reduce emissions, different types of biocombustibles were tried, derived from organic sources such as kitchen grease, algae, wood, and seeds. In the case of seeds, it was quickly established that they should be from plants that did not involve encroaching on land used for raising crops, but rather they should be plants that grow on land unsuitable for those destined for human consumption; this was to discourage farmers from replacing food crops with others that might be more profitable, leading to potential food shortages.

In 2008, the British airline Virgin Atlantic conducted the first comercial aircraft flight using biocombustible fuel, and on 3 October 2011 Iberia added itself to the list of airlines following suit. Its first flight of this type was on an Airbus A319 EC-KNM from Madrid to Barcelona, using a mix of 75 percent kerosene and 25 percent of biofuel derived from camelina sativa, a type of flax plant also known as “gold of pleasure” and “false flax”.

Iberia collaborated with Honeywell UOP, which raised the plants in the United States and processed it into biofuel in Mexico; with the Spanish oil giant Repsol, which tested and certified the fuel;  and Airbus, which acted in a consulting capacity. Honeywell took four months to successfully produce the proper mix for the flight, which ended up consuming 2,300 kilograms (5,070  pounds) of fuel.

Much of the camelina plant is processed into animal feed, but it also yields an oil used in the production of soap and paint, as well as some foods for human consumption, as it contains a high percentage of Omega-3 fatty acids – more than half of which are polyunsaturated (making it one of the “good” fatty acids). Camelina is also a second-generation biocombustibles source – meaning it doesn’t compete with any plant, unlike for example palm oil or sugarcane extract. It also has the advantage that it can be grown in fields otherwise dedicated to raising grains but left fallow to regenerate (one year out of every three), since camelina’s nutritional requirements are just 20 percent of those of grains like wheat and barley.

Two big drawbacks of SAFs are their availability and cost – much higher than kerosene refined from petroleum. In 2019 they made up just .1 percent of fuels used in commercial aircraft. But factories manufacturing biocombustibles from various sources are currently being built all over the world; for example, in 2020 IAG invested 400 million USD in a company called Velocys, which manufactures SAF from garbage.

And just this past 3 November the second Iberia flight using biocombustible fuel – its use being an option that Airbus now offers all its clients – took place between Madrid and Bilbao on an Airbus A320neo EC-NJY (which by the way burns 15 percent less fuel than its predecessor the A320, adding up to 5,000 fewer tonnes of CO₂ per year as well as 50 percent less nitrogen oxide). During IBE426’s 41-minute duration, this fuel economy – in addition to the SAF and the utilisation of electric vehicles for handling and towing the aircraft from its parking position – it’s estimated we achieved an emissions reduction of 1.4 tonnes of CO₂.

And on this flight, Repsol’s role was not just in testing the fuel but in producing it this past August from waste material in a refinery belonging to its subsidiary owned by its subsidiary Petronor in Muskiz (in the Basque province Vizcaya). This was the first intiative resulting from the agreement signed last July between Repsol and Iberia regarding low-emissions aircraft fuel.

According to a statement from Repsol, “This batch of biocombustible jet fuel is the third one manufactured by Repsol and the first on the Spanish market produced from waste as a primary ingredient. We have integrated tools of circular economy in the process, transforming this waste into high-added-value products, low-carbon-footprint fuel. This batch is being added to the two other previous ones, produced from biomass in Repsol’s refineries in Puertollano and Tarragona”.

Parto of the carbon-emissions savings we mentioned was achieved also using a “green” flight, with a direct ascent to 31,000 feet cruising altitude, which was maintained for three minutos before initiating an almost continuous descent (the rate of descent had to be reduced when intercepting the runway 30 locator), which one in which the aircraft descends with its engines idling, allowing gravity and every aircraft’s glide capacity to take it down to the runway without using its engines to slow its descent or fly farther (compare it to driving downhill in a car in neutral gear), minimising fuel consumption and therefore emissions.

This flight is the first milestone in the Iberia-Repsol agreement’s roadmap, which includes other upcoming flights with low-carbon biofuels in order to achieve more sustainability and efficiency in the aviation sector, where electrification is not feasible at present and renewable hydrogen requires a technological advance in aircraft, so biofuels will be the fastest and most efficient option to reduce transportation emissions in the coming years.