[OPINION] The High-Flown Fantasy of Aviation Biofuels

[Read the opposing view, “Takeoff for Aviation Biofuels: How, Where, When?” by Jim Lane, editor and publisher of Biofuels Digest.]

– by Almuth Ernsting, Co-Director, Biofuelwatch

On 24th February 2008, pictures of Richard Branson tossing a coconut into the air next to an aircraft at Heathrow were broadcast around the world, as he announced the world’s first biofuel flight. Biofuel, he claimed, would “enable those of us who are serious about reducing our carbon emissions to go on developing the fuels of the future.”

Environmental NGOs denounced his test flight as a publicity stunt, intended to deflect attention from the fact that aviation is one of the fastest growing sources of greenhouse gas emissions worldwide, and most carbon intensive form of transport. As far as Branson and his airline, Virgin Atlantic, were concerned, the flight was indeed no more than a stunt: The “biofuel test flight” burned 95% ordinary kerosene and just 5% biofuels, made from coconut and Brazilian babassu nut oil. Virgin Atlantic has not used any biofuels since that day.

Since then, however, at least 24 other airlines have blended biofuels with kerosene. By September 2015, more than 2,050 such flights had taken off, most by commercial airlines, some by the US and Dutch military and US and Canadian research institutes. This year, KLM has launched a series of 80 passenger flights with biofuel blends, and since March, United Airlines has been using such blends for regular flights between Los Angeles and San Francisco. They aim to expand their use to all their flights out of Los Angeles. Across the aviation industry, biofuel use and investments have moved far beyond what could be considered a mere publicity stunt.

Even if biofuels were carbon neutral – which is far from the case – there is no realistic prospect of them making any significant dent in aviation’s contribution to global warming. Between 2002 and 2012, global jet fuel use increased by one-fifth, to 5.42 million barrels a year (around 695,000 tonnes). Apart from a minor dip during the global financial crisis in 2008-2009, it has been growing year after year. Global biofuel production has reached the equivalent of around 70.8 million tonnes of oil a year, accounting for little more than 2% of the world’s transport fuels. However, as we shall see below,only a small fraction of the biofuels which are being produced annually today could conceivably be upgraded for use in aviation. Nearly the world’s entire biofuel infrastructure is for ethanol and biodiesel, which cannot be used in aircraft.

When discussing carbon emissions from aviation, it is important to note that the climate impacts of aviation are much greater than those of its CO2 emissions alone: As well as CO2, airplanes emit water vapour, oxides of nitrogen (NOx) and soot at high altitude, all of which have a significant warming impact. This is partly due to the fact that NOx increases ozone, which causes warming, particularly in the upper troposphere (where planes fly), and partly due to cirrus clouds formed by contrails.

There is uncertainty about the scale of the non-CO2 climate impacts of aviation, but there are credible estimates that they could double the warming impacts of aviation’s CO2 emissions. Swapping some fossil fuels for biofuels does not affect those impacts, hence even if a ‘carbon neutral’ biofuel existed, burning it at high altitude is still likely to cause as much warming as burning an equivalent amount of fossil fuels at ground level.

The reason why the aviation industry is keen to be seen to invest in biofuels are obvious: International aviation has been exempt from emissions reduction commitments under the Kyoto Protocol, and the industry is keen to ensure that its year on year growth won’t be hampered by climate policies in future.

When the EU passed a law to include the sector in its Emissions Trading Scheme from 2012 the industry managed to put enough pressure on policymakers to get this measure postponed until the start of 2017, and it now hopes to get it suspended again. Inclusion in the EU Emissions Trading Scheme, far from stopping the growth in aviation emissions, would merely oblige airlines to pay for dubious “offsets” if they exceed what tend to be highly generous carbon allowances given to polluters. The price of a tonne of carbon, i.e. of carbon offsets, has been falling drastically in recent years. However, for airlines, a principle is at stake: the principle of a total exemption from any climate policy that possibly resembles regulation.

The “alternative” put forward by the International Air Transport Association (IATA) since 2009, is a voluntary commitment to improve fuel efficiency by 1.5% per year until 2020 and then to achieve “carbon neutral growth.” IATA’s “commitments” could soon be enshrined into international policy drawn up by the International Civil Aviation Organisation (ICAO), a specialised UN agency. The two planks to the “carbon neutrality” proposal are biofuels and an new carbon offset scheme for aviation. The latter has been denounced by over 80 civil society organisations.

Compared to the current growth in aviation, the scope for cutting emissions through greater fuel efficiency is minor: Since 2010, new aircraft have become 1.1% more efficient a year, but IATA forecasts an annual growth of 4.1% in annual air miles. Aircraft are only replaced every 25-30 years, so any technical improvements are very slow to have an impact on fuel use.

There are no other possible techno-fixes for aviation: whereas electric cars are an option for road transport, planes can only fly by burning carbon-rich fuels, i.e. fossil fuels or specialist biofuels.

The only “alternative” proposed would be the use of liquid hydrogen. This, too, is highly problematic because planes would need to be much larger to incorporate bigger fuel tanks, which would require them to fly at higher altitude, i.e. in the stratosphere. Burning hydrogen emits water vapour, which is harmless at ground level, but causes significant warming it in the stratosphere – more than the global warming attributed to aviation emissions at present.

Biofuels are thus of great political importance to the aviation industry, even if their role in terms of fuel supply remains insignificant. Yet, as we have seen with biofuels for road transport fuels, replacing a very small fraction of fossil fuels with bioenergy can have disproportionately large adverse impacts. Biofuels and biomass electricity have by far the greatest land footprint of any form of energy. This is due to the fact that photosynthesis is of an order of magnitude less efficient at capturing solar energy than solar PV.

Like everybody else in the biofuel industry, the aviation industry claims to only be interested in “sustainable biofuels.” So how different will those be from biofuels used in cars today?

So far, four different types of biofuels have been approved for use in commercial aircraft: One is based on gasification and a process called Fischer-Tropsch reforming. The process was invented in the 1920s but nobody has yet found a way of commercially producing such fuels, i.e. of producing them with acceptable energy balances and without constant disruptions due to technical problems. Several heavily subsidized projects in the US have ended in bankruptcy.

Another approved aviation biofuel is made from a product called farnesene. In 2013-2014, four airlines bought farnesene from a biotech company called Amyris, which produced the fuel with the help of genetically engineered yeast. Technically, farnesene use in planes was successful, economically it was a costly failure. Amyris incurred substantial losses on every gallon of farnesene they sold for biofuels. Judging by their production costs for another farnesene product, producing one barrel of biofuels would have cost the company over $3,000. Today, Amyris’s sales are largely confined to expensive personal care products.

The latest novel aviation fuel, to be approved is made from isobutanol. Air Alaska obtained this fuel for two of their flights earlier this year from a company called Gevo, which produces isobutanol from corn. Like farnesene, burning isobutanol-based biofuels in planes is technically feasible, but producing them is prohibitively expensive and extremely difficult.

Gevo has been trying to produce it in a refinery in Minnesota since May 2012. During the first six months of this year, they incurred losses of $19.3 million on production alone, which means that it cost them that much more money to make biofuels than they earned from selling them. This is particularly remarkable because so far, Gevo has mainly produced conventional corn ethanol, which they would presumably have sold at a profit. This suggests that the losses from their limited isobutanol production must have been even higher.

This leaves one other type of aviation biofuels, made from Hydrotreated Vegetable Oil (HVO) or Hydroprocessed Esters and Fatty Acids (HEFA). Unlike Fischer-Tropsch biofuels, farnesene and bio-isobutanol, HVO production is relatively straightforward and already happening on a commercial scale. So far, most HVO is sold for use in cars, but it can be quite easily (if more expensively) upgraded to jet fuel.

HVO can be made in purpose-built refineries, or in upgraded crude oil refineries, though not in biodiesel plants. Leading producers of HVO include the Finnish oil company Neste Oil, Honeywell subsidiary UOP (who provide the technology to various companies), and the Italian oil company Eni. Other big players include AltAir (who have a partnership with UOP) in Texas, Diamond Green Diesel and Renewable Energy Group in Louisiana, Preem in Sweden, UPM in Finland, and Cepsa and Repsol in Spain. HVO relies on the same feedstock as biodiesel, i.e. largely on vegetable oil, though tallow and tall oil (made from a residue of pulp and paper production) can also be used.

In Europe, HVO production is heavily reliant on palm oil, used to make HVO by Neste Oil, Eni, Cepso and Repsol. Palm oil is by far the cheapest virgin plant oil. Its use in biodiesel is limited by the fact that diesel blended with a higher proportion of palm oil biodiesel solidifies at northern winter temperatures, but HVO overcomes this problem.

Airlines have so far been careful to avoid sourcing biofuels from palm oil, no doubt because they fear bad publicity, given that palm oil is widely known to be a leading driver of tropical deforestation, particularly in Indonesia and Malaysia. Sourcing used cooking oil clearly looks more sustainable, but the global demand for biofuels far exceeds the amount of used cooking oil or other waste sources available. Hence burning it in airplanes simply ensures that more biofuels made from palm or soybean oil will be burned in cars.

Greater aviation biofuel use would thus further push up the global demand for vegetable oil. Whether directly or, via price mechanisms, indirectly, this would push up the price of palm, soybean and canola oil and thereby make land conversion, particularly in the tropics even more lucrative.

At least as harmful, however, is the fact that the hype around aviation biofuels is being used to legitimise continued growth of aviation. Only a tiny proportion of the world’s population will ever step on a plane, yet global aviation emissions far exceed the total greenhouse gas emissions of most countries. If we want to avoid the worst impacts of climate change, there is no alternative to drastic curbs on aviation.

Almuth Ernsting is co-director of Biofuelwatch, a non-profit advocacy organization focusing on the impacts of bioenergy, based in the UK and US.

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