The high flown fantasy of aviation biofuels – Blog by Biofuelwatch

In a blog, Almuth Ernsting, Co-Director of Biofuelwatch, explains some of the issues with aviation biofuels, and the problems of ICAO hoping aviation can use them to get off the carbon “hook”. The reality is that only a tiny number of flights have been made using biofuels, with the only ones claiming to be genuinely “sustainable” being those derived from used cooking oil. There are various ways of making jet fuels out of biofuel, with the most successful and commercially viable one being HVO (Hydrotreated Vegetable Oil (HVO) or HEFA (Hydroprocessed Esters and Fatty Acids). Other processes are based on gasification and Fischer-Tropsch reforming; farnesene which is  produced from sugar using GM yeast; and producing fuel from bio-isobutanol.  HVO production is relatively straightforward, cheaper than the others, and already happening on a commercial scale.  However HVO relies largely for its feedstock on vegetable oil, though tallow and tall oil can also be used.  In Europe, HVO production is heavily reliant on palm oil, with its well known environmental /deforestation problems. Airlines have so far been careful to avoid sourcing biofuels from palm oil, fearing bad publicity.  Greater aviation biofuel use, from any vegetable oil, is likely to drive up demand and push up the global price of vegetable oils – making land conversion, particularly in the tropics even more lucrative.



[Read the opposing, pro-biofuels, 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 [see very useful table of which airline, date, blend, feedstock, distance travelled etc etc for all biofuel plane trips] 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 (around 695,000 tonnes) a year.  [From US Energy Information Administration EIA data].

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 around 70.8 million tonnes of oil equivalent in 2014 [ BP data] so far, 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 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 non-CO2 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 aviation 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 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:

1. 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.

2. 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.

3. 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.

4. 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 (if it used any form of oil that could be put to other purposes, such as palm oil, soybean oil, camelina oil, used cooking oil etc ) 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 [rape seed] 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 smaller 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.


Which airlines have so far used biofuels?

Interesting table showing which airlines have flown using any biofuels so far with drop down details on each.

For example,  one of the most recent listed start date:


Flight by Iata Code.  Lufthansa commercial flight – [FRA] to [TXL]
Blend %.  10%
Biofuel blend feedstock10% Farnesane (from sugar)
Start Date. 2014-09-15
End Date. 2014-09-15
Flight Frequency. Single flight
Number Flights. 1
Airframe Manufacturer Name. AIRBUS
Number Engines. Two of two engines
Q Biofuel Used. 400 Kilogram
Supplier Name. Total
Fuel TypeSIP
Producer NameAmyris
Key Conversion Process.  Conversion of biomaterial to farnesene using microorganisms, then chemical process to convert farnesene into farnesane.
Quality CertificationASTM D7566 Annex 3
Refuelling Airport Name. Frankfurt, Departure.
InfrastructureDedicated bowser truck
Plant Name. Amyris Brotas plant


i.e. This plane flew using fuel derived from sugar.  So that means it is in direct competition with human food.


Below is a small section of the table, showing the more recent flights.  More recent biofuel flights

See full table at   and click on each to see drop-down details of fuel, airline, amounts, date, manufacturer etc etc.   Many are single flights on one date.

A few have made many flights.  For example, the Air France one copied below:

Air France

Flight by Iata CodeAir France commercial flights – [TLS] to [ORY]
Blend %10%
Biofuel blend feedstock   10% Farnesane (from sugarcane)
Start Date  2014-09-17
End Date  2015-09-17
Flight Frequency   Multiple flights
Duration Sequence  1 year
Number Flights   52
Seats Flown   212   (sic)
Airframe Manufacturer Name    AIRBUS
Engine Manufacturer Name   CFM International
Same Type  yes
Same Blend  yes
Same Supplier  yes
Number Engines.  Two of two engines
Q Biofuel Used.   125 tons (10% blend)
Sustainability Certification   RSB / Bonsucro
Tons Carbon Saved      Single FlightAround 0.5 tons
Supplier Name   Total
Fuel Type   DSHC
Producer Name   Amyris
Key Conversion Process    Direct sgar to hydrocarbon
Blending Player Name   Total
Quality Certification    ASTM D7566
Refuelling Airport Name   Toulouse Blagnac (TLS)
Infrastructure   Supply is made by a dedicated normal truck.
Feedstock  Sugarcane
Plant Name   Amyris Brotas plant


In the EU debate, NGOs were pushing for a cap on all land-based biofuels as a response to ILUC (albeit with very little success – the cap was set far higher than what NGOs had wanted).  But some are still maintaining that there are land-based biofuels (as opposed to waste-based ones) which don’t result in significant land use change.  That, of course, is wishful thinking.
The “Roundtable on Sustainable Biomaterials” (RSB:) have certified Addax Bioenergy in Sierra Leone, a project which has been investigated in detail and denounced by several NGOs for worsening hunger and malnutrition, for land-grabbing, and for having gone ahead without the free, prior and informed consent of local communities.  See for example ActionAid’s 2013 report: .  That certificate (granted before the ActionAid report and maintained since then) completely undermines the credibility of the RSB.
It may be that the technical potential for aviation biofuels is ultimately as high as the technical potential for biodiesel.  A rapid scaling up of aviation biofuel production would be possible with enough investment and incentives/subsidies.
The only commercially viable way of making aviation biofuels involves hydrotreated vegetable oil (HVO).  HVO is made from exactly the same feedstocks as biodiesel.
Jet fuel made from HVO is approved for blends in commercial flights and accounts for almost all the aviation biofuels tested/used so far.  The only exception of which Biofuelwatch is aware was Alaska Airlines’ limited test light programme in June (2 flights) for which they used upgraded isobutanol from Gevo.  This is made from corn mash (i.e. the same feedstock as corn ethanol).
Gevo has been trying to commercially produce corn-based isobutanol since 2012, and they’ve had very limited success.  What little they have produced has incurred huge financial losses (i.e. losses incurring from production costs exceeding sales costs).  They’ve mainly been making ethanol and have used those residues to cushion the losses from isobutanol production.  So it’s been a massive failure so far.
Gevo keep speaking about making isobutanol from wood in future but the difficulties and costs involved in that are of a whole different dimension than those associated with what they’ve been trying so far.
HVO-based jet fuel is much more straightforward.  Across the EU, HVO production in 2015 was estimated as 2.36 billion litres (compared to 11.12 billion litres of biodiesel produced in the EU).
Also, HVO is more energy dense than biodiesel, so a litre of HVO gives you more energy than a litre of biodiesel.  It is actually easier to upgrade crude oil refineries than conventional biodiesel refineries to HVO production.  That’s what Neste Oil and Eni amongst others have done.  See the relevant sections about HVO here: .
From that report, it looks as if up to 25 billion litres of HVO could be produced with existing infrastructure, i.e. more than twice the EU’s biodiesel production (though I guess some extra investment in upgrading HVO to jet fuel would be required).  [A barrel is about 159 litres. So 25 billion litres is about 157 million barrels]. 
HVO production isn’t just targeted at the aviation sector.  It has the other ‘advantage’ that it can make higher palm oil biofuel blends compatible with car engines during the European winter (palm oil biodiesel solidifies at low temperatures).  But HVO producers are generally speaking about the possibility of making jet fuel.
All of this makes the aviation biofuels debate even more alarming.  We’ve all seen the disastrous impacts of biodiesel, so another market for exactly those same feedstocks has to be disastrous, too.
Palm oil use is particularly high European HVO.  So far, airlines seem to have been understandably reluctant to use any palm oil based HVO.  Diverting used cooking oil from use in cars to jet fuel makes for much better PR for them.
But if an aviation biofuel market was established through public incentives in future then god or bad PR won’t matter so much any longer.
From personal communication with Biofuelwatch.


More about biofuels, and how they are not as great a solution as their proponents hoped they would be