Sustainable Alternative Fuels
Progress Paper
Summer 2010
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Sustainable Alternative Fuels for Aviation
Summer 2010
Summary
•
Sustainable fuels, derived from biomass and mixed with kerosene, have
considerable potential to reduce net CO2 emissions from the airline
sector in the UK.
•
There have been several successful demonstration flights using
blended fuels and it has been shown that certification standards can be
achieved.
•
However, the extent to which the full potential of these alternative fuels
can be realized is still unclear.
•
Key issues include sustainability criteria and availability of adequate
land and/or marine space.
•
In order that the UK carbon inventory can benefit from sustainable
aviation fuel, government at national, regional and global levels has an
important part to play in development of the regulatory and fiscal
background.
•
Sustainable Aviation believes that a significant part of the revenue from
aviation trading activities within the EU ETS and other environmental
economic instruments should go into sustainable biofuel feedstock
cultivation and developing processing or refining capacity.
•
In the meantime, the monitoring, reporting and verification requirements
associated with aviation's entry into the EU ETS must be amended as
soon as possible to enable airlines to account for the use of lower
carbon fuels.
•
Alternative fuels are developing rapidly – this brief review will be
updated at appropriate stages.
1. Sustainable alternative fuels
When the Sustainable Aviation Strategy was first published in 2005, it contained a
commitment to “Review periodically the potential and practicalities of alternative fuels
to aviation kerosene”. Since 2005, considerable progress has been made in
evaluating and testing alternatives to traditional crude-oil derived kerosene. This is a
rapidly developing field and this brief paper is a summary of the situation at this time.
A directory of more detailed information and papers can be found at the end of this
brief.
Aviation fuels derived from biomass will form a key component of the industry’s longterm sustainable growth, complementing advances in engine and airframe
technology, operational practices and air traffic management. This position remains
unaffected by the shorter-term debate concerning the most appropriate application
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for bio-derived fuels in the near future, pending the wide-scale decarbonisation of the
power sector and electrification of the ground transport sector.
Globally, the aviation industry burns over 200 million tonnes of fuel per year. This
gives an idea of the scale of a potential market for sustainable jet-fuels, even if only
for displacement of a small fraction of global kerosene usage. Hybrid technologies,
fuel cells and rechargeable vehicles are already in use (or at advanced stages of
development) for the ground transportation sector. Commercial jet aircraft are an
ideal market for the emerging biofuel sector.
Aviation fuel is not defined by chemical composition. Thus, there is no requirement
for sustainable fuels to replicate the precise composition of current aviation fuel,
derived from crude oil, which in fact varies in chemical composition. However,
composition is important in broad terms as it determines the physical and chemical
properties which are required for performance and for certification. This challenge
has already been met through the production of jet fuel from coal in South Africa.
Coal, however, is not a sustainable source.
Sustainable Aviation supports the development only of sustainable fuels, which must
meet at least the following requirements:
1. Meet or exceed existing international jet fuel standard specifications;
2. Have a significantly lower life-cycle carbon footprint than conventional jet fuel;
3. Do not cause deforestation or the loss of high-value ecosystems;
4. Do not compete with food production for land or freshwater;
5. Retain social and economic benefits in the communities in which they are
produced;
6. Have the potential to be produced at a sufficient scale to generate a material
reduction in global aviation’s life-cycle GHG emissions on a carbon-equivalent
basis (i.e. taking into account emissions of other Kyoto gases)
We recognize the need to develop internationally accepted standards and support
the work of relevant organisations in this area. Considerable progress has already
been made in developing a sustainability benchmark for aviation biofuels.
2. Feedstocks, technologies and standards
The classification of biofuels is still somewhat confused as a result of the range of
developments.
2.1 Feedstocks
'First-generation biofuels' are biofuels such as ethanol made from sugar and
starch, or diesel from vegetable oil or animal fats. The basic feedstocks for the
production of first generation biofuels are often seeds or grains such as wheat, from
which starch is fermented to produce bioethanol, or sunflower seeds, which are
pressed to yield vegetable oil for use in biodiesel. These feedstocks could be used in
feeding animals and humans, and with an increasing global population, their use in
biofuels has been criticised for diverting food from humans, leading to food shortages
and price rises. Other concerns include deforestation and the clearing of land, or
conversion of agricultural land, for the cultivation of biofuel feedstocks. Sustainable
Aviation does not consider such fuels to be sustainable
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Second-generation (2G) biofuel production processes can use a variety of
feedstocks from non-food crops and sources. These include waste biomass, the
stalks of wheat, corn, wood, and special energy-or-biomass crops (e.g. Miscanthus
giganteus, a rapidly growing plant sometimes referred to as “Elephant Grass”). Many
second generation biofuels are under development such as biohydrogen,
biomethanol and biodiesel; however, only fuel with appropriate properties that can be
mixed with kerosene is suitable for use in aviation.
2.2 Technologies
There are two main technologies for producing biojet fuel:
•
Fischer Tropsch1 (in which the feedstock is first converted to a mixture of
carbon monoxide, hydrogen and hydrocarbons with the subsequent catalytic
process leading to a mixture of hydrocarbons)
•
Hydrogenation of biomass fatty acids and oils (for example from jatropha or
algae)2
It is also feasible to produce liquid fuels derived from lignocellulose in plants, woody
material which can constitute the bulk of plant matter.
2.3 Standards
Sustainably produced aviation fuels, as well as meeting points 1-6 above, require no
changes to aircraft engines and fuel systems or fuel supply infrastructure. That is,
they must offer a “drop in” alternative to conventional fossil-fuel based kerosene. To
make a significant contribution to reducing net CO2 emissions, there must be
potential for large-scale production of feedstocks and refining capacity. Globally
recognized sustainability standards must be adhered to. Fuels from such new
sources must be capable of being blended at ever-increasing ratios within the
commercial aviation fuel supply chain. If this can be done, which looks increasingly
likely, the potential environmental and energy security benefits are considerable.
In 2009, ASTM International (the fuel standards body for commercial aviation)
approved “D7566 - Standard Specification for Aviation Turbine Fuel Containing
Synthesized Hydrocarbons” and also its incorporation in “D1655 - Standard
Specification for Aviation Turbine Fuels” (that is JET A / JET A-1 – more generally
known as kerosene). This has allowed blends of up to 50% of SPK (synthetic
paraffinic kerosene) fuels to be produced using the Fischer Tropsch process, for use
on commercial aircraft. The FT process can be used to make fuels from coal (CTL,
coal to liquid), gas (GTL, gas to liquid) or bio-mass (BTL, biomass to liquid); only
biomass is an appropriate feedstock for sustainable alternative aviation fuel. This
certification standard takes into account stringent safety requirements.
A report is presently being compiled to expand the types of fuels covered by D7566
to include hydrogenated fatty acid SPKs, the relevance of which has been
1
Gasification is a process that converts carbonaceous materials, such as coal or biomass, into carbon monoxide and
hydrogen by reacting the raw material at high temperatures with a controlled amount of oxygen and/or steam. The
resulting gas mixture, synthesis gas, is further converted by the Fischer Tropsch process to liquid hydrocarbons,
which can be refined to produce a kerosene substitute.
2
BioSPK / kerosene blends have been successfully tested with biofuel derived from jatropha, a succulent plant with
inedible seeds that can be grown in marginal land, and from camelina, which belongs to the same family as oil-seed
rape and can be grown as a rotational crop when land would otherwise be fallow. Other potential sources include
biomass waste and algae and plants that are salt tolerant or halophytic (salt liking).
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demonstrated on three flights in late 2008 and early 2009 on commercial aircraft. The
report will use data from these demonstration flights along with data from the USA
military and will cover fuels from different suppliers (i.e. EERC, ENEOS, Neste Oil,
Syntroleum & UOP), which are being developed using their own patented processes.
Inclusion of these fuels in D7566 is anticipated in 2011.
3. Successful trials with biofuels
The industry continues to make progress in testing bio-derived replacements for
kerosene, characterising their physical and chemical properties, as well as their
performance in flight and on the ground.
SA members have participated in several different programmes to test the potential
of lower carbon, alternative fuels:
•
Feb 2008: Airbus A380 gas-to-liquid (GTL) demonstration flight – partnership
with Rolls-Royce, Shell and Qatar Airways and subsequent GTL revenue
flight in Oct 2009. The GTL process pointed the way to development of
processes for manufacturing sustainable biofuels.
•
Feb 2008: Virgin Atlantic biofuel “proof of concept” flight – partnership with
Boeing, GE and Imperium.
•
Dec 2008: Air New Zealand demonstration flight with Rolls-Royce as a
partner– 50% jatropha-based SPK blend in one engine.
•
BA and Rolls-Royce have announced a programme of ground tests on
alternative fuels
•
Also demo flights by: Continental (jatropha & algae), Japan Airlines
(camelina, jatopha & algae) and KLM (camelina).
•
British Airways, in partnership with the Solena Group, is to establish Europe's
first sustainable jet-fuel plant and plans to use the low-carbon fuel to power
part of its fleet from 2014.
•
Airbus has called for more research and development of algal-based biofuels
with a goal of 15% of all aviation fuels from such sources by 2030. Qatar
Airways, with Airbus support, has recently announced ongoing biomass-toliquid BTL project.
SA in its “CO2 Road Map” has assumed a 50% lifecycle saving in GHGs for each litre
of kerosene displaced. IATA has estimated 60-90% for biomass to liquid fuels –
some other estimates of carbon savings are higher (see the Committee on Climate
Change report listed at the end of this document).
4. Bringing to market
Processing technologies currently being developed can convert second generation
feedstocks into fuels which meet or exceed the stringent performance criteria of
conventional jet fuel. Although biofuels are not yet in routine use for commercial
aviation, BTL is already certified for use and technical certification is proceeding
rapidly for other 2G biofuels. It is expected that “drop in” biofuel/kerosene blends will
enter the normal jet fuel supply chain within the next few years. The CO2 roadmap
[Figure 1] published by SA in 2008, offered a conservative assessment that 20% of
fuel for UK departing flights would come from sustainable alternative sources by
2050, contributing to a 10% cut in absolute CO2 emissions. IATA, representing 93
percent of the world’s carriers, has set a goal of drawing 10 percent of its fuel from
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renewable sources by 2017. The UK’s Committee on Climate Change estimated a
similar contribution to that in the SA road map while indicating that this was
conservative in comparison to some other predictions [Figure 2]. The Air Transport
Action Group (ATAG) has suggested that with 15% and 30% consumption of biofuel
in 2020 and 2030, the EU aviation industry will be able to avoid 35 million tonnes of
CO2 emissions in 2020 and 100 million tonnes in 2030. A study by eq2Insight has
pointed to the economic attractiveness of biofuels.
Through internationally recognised bodies such as the Commercial Aviation
Alternative Fuels Initiative (CAAFI) and the Roundtable on Sustainable Biofuels
(RSB), the supply of biofuel for aviation [Figure 3], subject to common sustainability
standards, can be developed at a global level. The supply chain for aviation is at a
very early stage of development, so, in addition to other sustainability criteria, it is
essential that new fuels being produced for our sector have verifiably lower life-cycle
GHG footprints than current crude oil-based jet fuel. They must, of course, also meet
technical standard requirements such as the UK MoD Defence Standard 91-91 and
ASTM International D1655.
In order to optimise use of sustainable, lower carbon biofuels by the aviation sector,
procedures will need to be developed, internationally, to account for their usage and
to allow for flexibility within the aviation biofuel supply chain.
5. Land and water – area requirements
Clearly the availability of land or water for cultivation will be important. Aviation
consumption of fuel is set to rise as countries like India and China develop their
networks.
An E4tech study reported by IATA suggests that fully replacing jet kerosene by 2050
would require approximately 37 million hectares for new oil crops (camelina, jatropha,
algae) and 194 million hectares for energy crops (for BTL), a total of 231 million
hectares. The use of residues and waste would reduce the land use required for
energy crops.
This estimate is roughly equivalent to around 16% of the land currently under
cultivation around the world, although lower quality land not currently being cultivated
could be used. There is an estimated 386 million hectares of marginal land3 globally,
which would be suitable for the new oil crops (IATA, 2009). It has been reported that
yield advantage would not outweigh the cheaper cost of marginal land, so, demand
for arable land on which to grow new oil crops should be minimal.
Boeing has estimated that a much smaller area of the size of Belgium, some 3 million
hectares, would be required to fuel the current commercial aviation fleet using fuel
derived from algae, grown in water, possibly salt water, in hot climates. Of course
area requirements, whether land or water, will depend on factors such as the
geographical location, climate and nutrient supply.
By 2012, when aviation will be required to comply with the EU Emissions Trading
Scheme (EU ETS), the relevant cost hurdle for aviation biofuels to overcome will be
the market price of jet kerosene plus the cost of buying carbon or CO2 allowances to
offset the emissions resulting from burning that fuel.
3
In farming, poor-quality land that is likely to yield a poor return. It is the last land to be brought into
production and the first land to be abandoned.
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SA believes that a significant part of the revenue from aviation trading activities within
the EU ETS and other environmental economic instruments should go into
sustainable biofuel feedstock cultivation and developing processing or refining
capacity, to provide a lower carbon alternative for aviation and other transportation
sectors. SA is concerned, however, about the potential negative unintended
consequences associated with mandatory targets on UK or EU-departing airlines.
SA recognises that much more work must be done to assess the sustainability of
feedstock cultivation, and the land-area requirements related to production on a
sufficient scale. Government support for research in this area would facilitate
improved understanding of the life-cycle impacts of the various alternative
feedstocks, informing and complementing the technical work being carried out within
the industry.
6. Infrastructure and government
Although large amounts of oil are currently transported around the world, moving
biofuels from the centres of production [Figure 3] to major aviation hubs could negate
a part of the potential net carbon savings. Instead, it is likely to be more efficient to
use biofuels at local aviation hubs wherever possible. However, this begs the
question of aviation fuel supply at locations distant from both oilfields and biofuel
production centres; there is clearly work to be done on optimization of biofuel
distribution.
A system could be established, similar to renewable electricity tariffs in the UK,
whereby airlines could agree to purchase a certain volume of fuel from sustainable
sources as part of their contract with fuel suppliers. A volume of biofuel, equivalent
to the contracted amount, would be guaranteed to enter the aviation fuel supply chain
somewhere in the world but would not necessarily be used by the contracting carrier.
The carrier would, however, receive the benefit of any carbon savings associated
with the cultivation of the fuels (e.g. a 50% saving compared with conventional jet
fuel) and could include this in their carbon reporting at the end of a trading period.
In the meantime, the monitoring, reporting and verification requirements associated
with aviation's entry into the EU ETS must be amended as soon as possible to
enable airlines to account for the use of lower carbon fuels. The current
requirements do not take into account normal operational practice at airports that
uses co-mingled (i.e. shared) fuel tanks. To effectively identify the carbon savings
associated with the consumption of biofuel, quantification and verification must be
done before the fuel enters co-mingled supply. In practice, this means that biofuels
must be monitored at the point of purchase and then a rigorous stock reconciliation
process must be followed.
Looking beyond the EU ETS, organizations such as the Aviation Global Deal are
strongly advocating a global trading system which could include biofuels and
pressure is growing on ICAO to develop global trading for the industry.
Clearly Government at national, regional and global levels has an important part to
play in development of the regulatory background. In the UK there is an additional
aspect in development of the considerable knowledge and expertise held in UK
universities and by UK businesses on second generation biofuels and transferring
this into commercial scale production, putting renewable technologies and lower
carbon fuels for aviation at the heart of the Government’s climate change agenda.
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7. Conclusion
SA recognises that biofuels do not represent a "silver bullet" for our sector's
contribution to climate change. However, in combination with a continued emphasis
on greater efficiencies and market based mechanisms such as carbon cap-andtrading, and as long as stringent sustainability criteria for these biofuels are
embedded in the emerging supply chain, biofuels can offer an opportunity to reduce
the carbon intensity of air travel for our passengers.
It is important that biofuels are recognised within schemes such as the EU ETS,
which is scheduled to include aviation from 2012.
The next few years should see rapid development of commercial scale projects and
development of trading in a global framework. The industry has clearly indicated its
willingness to move ahead in developing a significant aviation biofuel market. This is
a fast moving area, so the SA position on biofuels will be reviewed and updated on a
regular basis.
Further information:
ATAG (Air Transport Action Group), 2009. Beginner’s guide to aviation biofuels.
http://www.enviro.aero/Content/Upload/File/BeginnersGuide_Biofuels_WebRes.pdf
Biofuel Watch, 2009. Biofuels for Aviation. http://www.biofuelwatch.org.uk/
Biofuels digest – a daily news publication covering all aspects of biofuels. www.biofuelsdigest.com
CAAFI (Commercial Aviation Alternative Fuels Initiative). http://www.caafi.org/
Committee on Climate Change, 2009. Meeting the UK aviation target-options for reducing emissions to
2050. http://www.theccc.org.uk/reports/aviation-report
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EQ Insight, 2010. Sustainable Flying: Biofuels as an Economic and Environmental Salve for the Airline
Industry. http://eq2.uk.com/pdf_resources/Aviation%20biofuel.pdf
Hileman et al. 2009. Near Term Feasibility of Alternative Jet Fuels. Rand Corporation, Santa Monica,
CA, USA.
IATA (International Air Transport Association), 2009. Report on alternative fuels.
http://www1.iata.org/ps/publications/alternative-fuels
Partner Project 28 Report. Version1.1.2010. Life Cycle Greenhouse Gas Emissions from Alternative Jet
Fuels. MIT, Cambridge, MA, USA.
Round Table on Sustainable Biofuels.
http://cgse.epfl.ch/webdav/site/cgse/shared/Biofuels/VersionZero/Version%20Zero_RSB_Std_en.p
df
Sustainable Aviation CO2 Road Map. http://www.sustainableaviation.co.uk
US Department of Agriculture/ US Dept of Energy, 2008. Sustainability of biofuels: future research
opportunities.
UNEP, 2009. Towards sustainable production and use of resources; Assessing Biofuels.
www.unep.fr/scp/rpanel/pdf/Assessing_Biofuels_Full_Report.pdf
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Figure 1: SA CO2 Roadmap - projected future emissions of CO2 from UK aviation
Source: Sustainable Aviation www.sustainableaviation.co.uk
Figure 2: Scenarios on proportion of biofuel penetration
Source: Committee on Climate Change www.theccc.org.uk
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Figure 3. Optimal land for growing sustainable aviation biofuels
Source: ATAG www.enviro.aero
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