"BIOFUELS"

Pressure on the aviation industry to balance increasing demand with environmental protection is at an all-time high, according to the International Civil Aviation Organisation.

The sustainability of the aviation sector is increasingly in the spotlight, thanks to its impressive growth rate and the fact that it uses so much fuel. This is reflected in the EU's move to include it in its Emissions Trading System and ICAO's tortuous progress towards a global scheme.

The industry collectively agreed in 2008 to the world's first sector-specific climate change targets, including a commitment to continue improving fleet fuel efficiency by 1.5% per year until 2020.

From 2020, aviation will cap its net carbon emissions and by 2050, the industry has committed to reducing its net carbon footprint to 50% below what it was in 2005. In addition, the European Commission wants to see 4% of aviation fuel coming from bio-based sources by 2020.

There are plenty of ways to make aircraft more fuel efficient, from winglets to lightweight composite materials to more efficient engines. But when it comes to fuel, aviation is different from other forms of transport in that it has little alternative to liquid fuels - electrification is not an option because batteries are too heavy and do not provide enough power to get an aircraft off the ground.

As a result, according to Tom Enders, former chief executive of Airbus and now chief executive of EADS, "the production and use of sustainable quantities of aviation biofuels is key to meeting our industry's ambitious CO2 reduction targets". And given the relatively small size of the aviation fuel market compared with other forms of transport, it is hoped that in time, biofuels will play a major role in improving the sustainability of air travel. Analysis suggests that biofuels will reduce overall life-cycle CO2 emissions by 80% compared with traditional jet fuel.

Already, significant progress has been made - from a standing start in 2007, more than 1,500 passenger flights have been made using biofuels produced from feedstocks ranging from household waste to excess gas, industrial processes and algae.

The major challenge now is to work out how to produce large quantities of sustainable biofuel at a cost that is commercially competitive to airlines.

At the moment, biofuel costs around three times as much as conventional jet fuel, although this is expected to fall as production capacity is increased beyond the current small-scale projects.

At the same time, Jet A-1 prices are expected to head in the opposite direction as conventional oil becomes scarcer and harder to obtain.

However, in the short term, the scaling-up process has been held back by the sector's caution about using biofuels that are not sustainable, including first-generation fuels made from feedstocks such as corn that compete with food for resources or those made from palm oil grown on land cleared from rainforest, which have a huge impact on emissions. "Sustainability is a must for us," stresses Frederic Eychenne, new energies programme manager at Airbus.

The aviation industry took careful note of the negative effects when the first generation of biofuels were deployed in road transport and is determined not to repeat those mistakes, says the industry pressure group Aviation Benefits Beyond Borders. In addition, many of these fuels were unsuited to aviation - ethanol does not have the required energy density, while biodiesel has a tendency to freeze at high altitudes.

The other factor that has to be taken into account is the need for any sustainable alternative fuel to be of "drop-in" standard, so that it has the same chemical properties as conventional jet fuel. With drop-in fuel, "no new engines, no new aircraft and no separate fuel delivery systems are needed at airports," says the Air Transport Action Group (ATAG). "It is the most practical solution. More biofuel can be added to the system as it comes on stream."

This leaves companies dependent on new feedstocks that do not cause deforestation or other environmental impacts and that do not compete with food crops for land or water. But before a particular type of biofuel production can be scaled up, it must first win certification from one of two certification bodies - ASTM, a US-based body that deals with standards for civil aviation, UK-based Def-Stan, which focuses on fuel for use in military applications, which have slightly different requirements, or the US Department of Defense.

It is not just the feedstocks that are under scrutiny but the production process. There are currently two approved processes for producing alternative aviation fuels, explains Richard Mills, UK director of strategy at Boeing. The first to be approved, as far back as 2009, was synthetic paraffinic kerosene (SPK) produced using the well-understood Fischer-Tropsch process that allows the use of a range of feedstocks, including municipal solid waste and various types of biomass.

The other approved process, which was certified in 2011, is known as hydro-processed esters and fatty acids (HEFA), which produces fuel derived from biomass feedstocks such as camelina, jatropha or algae. Certification of aviation fuels is an arduous process, says Mark Rumizen, who worked on the HEFA standard as lead of the certification-qualification group for the US-based Commercial Aviation Alternative Fuels Initiative (CAAFI). "Because of the great emphasis on safety when you're dealing with aviation fuel, the (certification process) required a collaborative and co-operative effort between the members of the aviation fuels community."

"Certification is a long process where everyone is involved, from the airframers to the engine manufacturers, to the component makers, to the regulators," says Eychenne. The whole process can take three to four years, he adds, and we are likely to be at least a decade away from having a large amount of alternative fuels on the market.

According to Mills, the next fuel pathway likely to be approved is the direct conversion of alcohol to jet (ATJ) fuel, which would enable airlines to use more fuel derived from bio-ethanol. Given that there are already large amounts of bio-ethanol on the market - principally from Brazil, where it is made from sugarcane and the US, where corn is the main feedstock - this would enable rapid scaling up to commercially viable quantities.

There is the added advantage that ATJ does not need to be blended with kerosene because it already contains aromatics. Critics, however, argue that the environmental benefits of burning ATJ fuels are minimal when the whole life cycle is taken into account, particularly with corn as the feedstock. Nonetheless, ATJ is likely to play a major part in the market - Brazilian airline Azul recently ran a test flight using ATJ supplied by Amyris during the Rio+20 sustainability conference.

Mills warns that no one fuel will be a silver bullet: "There will be a number of different winners because different feedstocks are appropriate in different parts of the world - we will see a portfolio of different fuels."

Boeing is working on algae in China, for example, as well as looking into using halophytes, a plant that grows in salt water, in the United Arab [Vous devez être inscrit et connecté pour voir ce lien].

Meanwhile, Airbus is researching the use of camelina in Romania and Spain and jatropha in Brazil, as well as the Mallee bush in Australia and algae in Qatar.

The aviation biofuels industry is still in its very early days, says Mills, and a lot of investment will be needed to allow the sector to cross the classic valley of death that afflicts new industries, "where the technology has been demonstrated at pilot scale and shown to work but it needs to scale up. However, banks are reluctant to invest until the first full-scale plant is up and running."

But as the industry matures, "further investment will allow us to look at new types of feedstock/pathway combinations that might offer better economics", he adds.

[Vous devez être inscrit et connecté pour voir ce lien] was not among the first airlines that conducted biofuel test flights over the past few years. But being in the front row is not important, says Joachim Buse, vice-president of aviation biofuel at the German carrier. "We rather stay a bit more in the background but have everything carefully worked out, with scientific support and, in the end, economically sensible results."

Last year, however, the Germans eventually taxied to the runway for their first partly biofuel-powered take-off - and nearly 1,200 departures followed as part of the airline's "burnFAIR" long-term trial, with support from the German Aerospace Center (DLR) and federal ministry of economics and technology.

Between 15 July and 27 December 2011, Lufthansa deployed a newly delivered Airbus A321 (registration D-AIDG) on the route between Hamburg and Frankfurt, with one of the two International Aero Engines V2500 powerplants running exclusively on a 50:50 synthetic biofuel-kerosene blend and the other using conventional Jet A1. The aircraft made the approximately one-hour journey up to eight times per day and consumed 1,556t of biofuel in total.

The point was not to see whether the alternative fuel burns in gas turbine engines - that had been demonstrated before - but to evaluate its long-term impact on performance as well as powerplant and fuel system health. "We wanted to make sure that we can safely fly on biofuel without problems," says Buse. "It makes no sense to plan further steps if biofuel leads, for example, to higher maintenance."

The test not only confirmed that the jatropha, camelina and animal fat-based mixture has no negative side effects on equipment and operations - it even showed a 1% lead in specific fuel consumption because of its higher energy density over Jet A1.

Biofuel is among the most promising means to cut aviation carbon dioxide emissions, with a potential to improve the CO2 balance by up to 60%, says Buse. But it also offers an opportunity to reduce the industry's dependence on fossil fuels and global oil-price fluctuations in the long term. The challenge is finding a way to supply the future fuel in sufficient quantity.

A member of Buse's team, which has been working on Lufthansa's biofuel strategy since three years ago, travelled to Russia in early June to inspect camelina fields in the Volga region, where the oil plant is being tested as a potential future crop. Local farmers tried to grow different sorts of wheat in the region, but abandoned a huge area of farmland over the past 10-15 years after numerous crop failures.

While oil mills have yet to be built to process the crops, he says that the area looks "very promising". The plant's oil yield would also need to be enhanced through modern growing techniques. But given that camelina is a well-understood traditional European agricultural plant, Buse sees no technical difficulties in employing the species.

Aside from providing local farming communities with a more stable economic source and the opportunity to establish a new industrial infrastructure, another advantage of re-utilising former agricultural land is that no compensation areas for biodiversity would need to be established. This would be required if untouched natural areas were to be converted to grow biofuel crops. Buse says that biofuel production should not lead to large monocultures.

Lufthansa is also looking elsewhere for potential areas to grow oil plants.

"We believe we should combine a portfolio of different (growing) methods and raw materials to achieve a more stable supply situation," says Buse. "Africa still offers very good field availability in the semi-arid, subtropical zone." Such areas would be suited to grow jatropha as the climate is too warm for camelina.

The airline is partnering with universities and associations around Germany's ministry for economic cooperation and development to combine its biofuel objectives with policies to establish viable and beneficial agricultural infrastructures for the local communities.

Buse has no illusions that biofuel will replace fossil-based kerosene anytime soon.

He thinks that employing 5% biofuel within five to seven years is feasible, while conventional Jet A1 will remain the main power source over the next 20 years. The main hurdles are locating enough agricultural land that is not suitable for growing food crops and establishing an integrated supply chain for biofuels.

While the fossil oil industry has a long-established integrated infrastructure - covering all stages from exploration to distribution - the biofuel sector is fragmented.

Oil plant growers are not linked up with biofuel refineries, who in turn have little contact with consumers. The existing bio-diesel business for ground vehicles is largely determined by intermediate traders who deal with raw materials in spot markets, says Buse. "Today, the end user is the only one (in the aviation biofuel supply chain) who is able to provide security that the final product will be taken up by the market."

While airlines will have to play a new role as their own fuel suppliers, Buse is confident that the necessary capital to establish such activities can be secured.

Given Europe's economic woes and the fact that government bonds have somewhat gone out of fashion recently, financiers are looking for new investment opportunities - and the agricultural sector has not been fully exploited yet. "We are in the comfortable position that the required funding is available from investors who are seeking long-term opportunities with average but safe returns."

Fuel additives are being developed, which should simplify the use of synthetic bio-kerosene in future. The mixture ratio with Jet A1 - currently limited by the standards authority ASTM International to a maximum 50:50 blend - depends on the fossil fuel's conditioning. If, for example, the Jet A1 sulphur content is low, it may not be mixed half and half with biofuel. Buse expects, however, that additives will become available in the next three to four years, which will allow using 100% bio-kerosene in aircraft. This will not only make the current safety-critical blending step obsolete, but also facilitate combined storage and distribution with conventional Jet A1.

Changing customer behaviour is one of two main factors driving Lufthansa's biofuel strategy. Pressure to make air transport more environmentally friendly has grown most strongly in the airline's cargo division, because commercial customers want to improve the green credentials of their goods and services.

But the trend is set to continue in the passenger business, not only from private travellers, who demand more responsibility toward the natural world, but also corporate clients who want more sustainable flights for employees, says Buse. "Today we can still put this off for a bit and claim that we would like to become more environmentally friendly, but the (biofuel) supply is not yet available. But pressure to become more engaged is unquestionably in the market. And I believe a customer-oriented company is best advised to respond to customer expectations."

The other main driver is the desire to secure a long-term alternative fuel supply to become less subjected to the volatile oil market.

Buse expects the price for Jet A1 to rise no matter how demand develops, firstly because exploration of new oil fields is set to become more expensive while the individual sources yield less return.

The second reason is that kerosene competes with other kinds of fuel, such as vehicle or domestic heating fuels, in terms of refinery capacity. With living standards rising around the globe, Buse expects petrochemical products such as car fuel to become more profitable than kerosene for refineries. So the price of Jet A1 will need to go up for it to remain lucrative. "I don't see that we cannot realise (the projected) aviation growth over the next 10 or 20 years because of a lack of fossil oil," says Buse. "The question is more: will we still be able to afford it?"

Michael Gubisch tweets as @MROreporter and writes news stories for our [Vous devez être inscrit et connecté pour voir ce lien]