As calls for action increase over the climate impacts of aircraft contrails, airborne research is intensifying with the expansion of two key projects in Europe and the US. In Germany, Lufthansa has started converting an Airbus A350-900 for use as a flying research laboratory as part of IAGOS-CARIBIC, a long-running European programme that uses commercial airliners to gather data on air quality for scientific evaluation. The A350 will be equipped with around 20 measuring instruments for a multi-year project beginning late next year to measure trace gases, aerosol and cloud parameters on selected long-haul flights. In the US, engine manufacturer GE Aerospace and NASA have just completed two flights with a Boeing 747 testbed aircraft to record three-dimensional imaging of contrails to better understand how they form and behave in certain conditions. The 747’s emissions were scanned using Light Detection and Ranging (LiDAR) technology installed on a following aircraft.

IAGOS (In-Service Aircraft for a Global Observing System) is a European programme established in 1994 to assess atmospheric composition, air quality and climate, using commercial jets as research platforms. There are currently 10 widebody Airbus A330 and A340 family jets from seven airlines deployed in the project, with another 10 having previously been used, again from seven participating airlines.  

The Lufthansa A350 selected for the IAGOS programme, registered D-AIXJ, is almost seven years old, and will add a new-generation airliner to the research fleet.

A measuring laboratory weighing two tonnes is being developed for the next phase of the programme, and once fitted with some 20 instruments, will be installed in the cargo hold of the A350 on selected scheduled flights from late 2025.

The onboard laboratory will be connected to the air intake system on the jet’s outer fuselage through permanently installed pipes, and used to measure over 100 trace gases, aerosol and cloud parameters from the ground up to the tropopause atmospheric region, at altitudes between nine and 13 kilometres.

The IAGOS programme is led by the Jülich Research Centre, one of Europe’s largest research organisations, which combines the expertise of global partners in weather services, airlines and the broader aviation sector.

The programme combines the complementary concepts of two research projects: MOZAIC (Measurement of Ozone, Water Vapour, Carbon Monoxide and Nitrous Oxides by Airbus In-Service Aircraft), which was funded by the European Commission between 1993 and 2004, and CARIBIC (Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container).  

Lufthansa, which with Air France was an IAGOS launch partner in 1994, has gathered climate-related data for research on more than 35,000 of its passenger flights over the three decades.

Together with the Jülich Research Centre and Karlsruhe Institute of Technology, the Lufthansa Group has fitted a total of six Airbus aircraft with measuring equipment since the programme was inaugurated to collect information about atmospheric conditions during scheduled flights.

Lufthansa currently has two aircraft, an A330 and an A340, deployed in the programme, as well as another A330 from sibling airline Eurowings Discover.

On December 9, the Eurowings jet was used to gather climate data during a 10-hour, 45-minute flight from Frankfurt to Orlando, Florida. The information was collected continuously while the aircraft flew at an altitude of more than 10,000 metres (33,000 feet) over a distance of 7,600 km.

Other airlines currently participating in the programme are Taipei-based China Airlines, with two A330s, and Air Canada, Air France, Cathay Pacific, Hawaiian and Iberia, each with one A330.

After each flight, climate information gathered by the aircraft is sent automatically to the database of Centre National de la Recherche Scientifique in Toulouse, France, from where it is accessible for global research.

The data is currently used by about 300 organisations worldwide to provide fresh insights into climate development and atmospheric composition and help refine climate models and improve weather forecasting.

“We are proud to have been able to make a significant contribution to climate research for 30 years,” said Lufthansa Group’s Chief Technology Officer, Grazia Vittadini. “Through our commitment, we are helping to sustainably improve climate models and weather forecasts. Scientifically-sound findings are the basis for targeted measures on the path for more sustainable aviation.”

GE/NASA contrail research flights

In the US, GE Aerospace and NASA have built upon a 50-year collaboration by performing two research flights for their Contrail Optical Depth Experiment (CODEX) in which three-dimensional imaging was generated of contrails created by GE’s Boeing 747-400 Flying Test Bed aircraft.

The 747 was trailed by a G-111 aircraft from NASA’s Langley Research Centre in Virginia, which deployed Light Detection and Ranging (LiDAR) technology to scan the wake of the larger jet, enabling researchers to use new imaging to better understand how contrails form and behave.

During the flight tests, 3D images were generated of contrails from all four CF6 engines on the 747. GE Aerospace was also able to isolate the contrails from a single engine on the test jet.     

The flights expanded the company’s capabilities ahead of flight tests it is planning during this decade to assess the performance of new commercial aircraft engine technologies, including Open Fan, advanced combustion designs and other propulsion systems.  

“Understanding how contrails act in flight with the latest detection technology is how we move innovation forward,” said Arjan Hegeman, GE Aerospace GM of Future Flight Technology. “These tests will provide critical insight to advance next generation aircraft engine technologies for a step change in efficiency and emissions.”

Dr Rich Wahls, manager of NASA’s Sustainable Flight National Partnership, welcomed participation “on this first-of-its-kind flight experiment” in helping to reduce the impact of contrails.

“NASA is advancing the scientific understanding of contrails to improve our confidence in future operational contrail management decisions that consider overall climate impact and economic trades,” he said.

NASA, German Aerospace Centre (DLR) and contrail forecasting and management company SATAVIA, are also working together on atmospheric forecasting to identify the best conditions for studying the formation of contrails. SATAVIA was recently acquired by Aerospace Carbon Solutions, a division of GE Aerospace.

In this collaboration, DLR will help to identify the altitude and dimensions of contrail-forming regions, so that flight tests can be conducted using the LiDAR technology to improve contrail prediction, while SATAVIA will use the flight test results to validate and improve its numerical weather prediction capability, used to forecast contrail formation conditions.

At this year’s Farnborough Airshow, the chief technology officers of GE Aerospace, Boeing, Airbus, Dassault, Rolls-Royce, RTX and Safran called for government support to expand research that enhances scientific understanding of aviation non-CO2 effects such as contrails, nitrogen oxides, sulphur, aerosols and soot.

Top photo: The first IAGOS system has been in use on a Lufthansa Airbus A340-300 since 2011

Bottom photo: GE Aerospace’s 747 Flying Test Bed

Tony Harrington

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SATAVIA has claimed significant reductions in climate-warming contrails from a range of commercial jet types during a 10-month test programme conducted last year on 65 flights operated by 12 airlines. The UK-based company said route optimisation developed using its DECISIONX contrail software had collectively avoided over 2,200 tonnes of carbon dioxide equivalent (CO2e), or an average of more than 40 tonnes per flight, with minimal impact on aircraft fuel consumption or flight distances. Contrails are formed in specific meteorological conditions which cause vapour to freeze around soot particles expelled from aircraft engines, creating cloudy canopies of ice crystals which can trap heat in the air and worsen aviation’s climate warming effects. SATAVIA’s software uses extensive atmospheric modelling data to help flight planners identify and avoid conditions in which contrails can form. Among the airlines participating in the tests were Icelandair, Kenya Airways, Condor and SunExpress, performing a mix of short, medium and long haul flights.

Aircraft contrails can either cool or warm the atmosphere by day, depending on conditions, while all contrails created at night cause warming. SATAVIA’s CEO, Dr Adam Durant, said identifying and avoiding conditions which enable formation of the most warming contrails provided a proactive and immediate mitigation strategy to help manage the non-CO2 climate impacts of aviation.

“We’re not reducing emissions, we’re avoiding the warming caused by the clouds aircraft can make,” he said, emphasising that contrail management was not a carbon offsetting measure. “We’re addressing what is known as a short-lived climate forcer, calculating the energy we’ve avoided and converting that to a CO2-equivalent mitigation.”

The  SATAVIA test programme, financially backed by the UK and European space agencies, enabled the company and the participating airlines to assess the contrail avoidance software in a wide range of routine operating environments. 

The company said the initial test results also highlighted a significant opportunity for a new voluntary carbon market segment as the aviation industry continued to seek ways to address its environmental impacts.

Additionally, said SATAVIA, the tests progressed its plans to secure endorsement from Gold Standard, the Swiss-based climate accreditation platform, ahead of an EU requirement from next year that airlines must monitor, report and verify their non-CO2 impacts as part of the European Union Emission Trading System (EU ETS).

Achieving accreditation from Gold Standard is a high priority for SATAVIA, which wants its contrail avoidance technology externally validated, and non-CO2 mitigation credits recognised and introduced for the aviation sector.

Having last year received concept approval from Gold Standard, SATAVIA is now undergoing design certification of its patented methodology, which it says will provide commercial incentives for airlines to voluntarily reduce their contrails before the practice is mandated.

“This new voluntary carbon market will be worth billions of dollars globally, creating a bottom-line rationale for operators to cut their non-CO2 climate footprint,” explained Durant. “As a low-cost, easy-to-implement software solution, contrail management can help move aviation towards climate-neutral operation on near-term timescales.

“We’ve shown that aircraft operators can use DECISIONX to minimise the warming caused by aircraft contrails and reduce their climate footprint with minimal impact on day-to-day operations,” he said. “We also invested in extensive scientific validation to support post-flight verification of avoided climate impact.”

SATAVIA has previously simulated tests of its software with Dubai-based Emirates, the world’s largest operator of long-haul flights, followed by in-service assessments with the national carrier of the United Arab Emirates, Abu Dhabi-based Etihad, with which the company has an extensive partnership.   

The latest test programme was performed last year with 12 participating airlines including Icelandair, Kenya Airways, Lufthansa Group’s Condor and SunExpress, a joint venture between Lufthansa Group and Turkish Airlines.

The study included both day and night flights operated by aircraft types ranging from Embraer regional jets to narrowbody and widebody Airbus and Boeing equipment.

The flights assessed in the programme were divided between short-haul services of less than three hours, medium-haul flights of three to six hours, and journeys of more than six hours. They included both passenger and freight flights, all of which were powered by conventional jet fuels.

As well as further evaluating SATAVIA’s contrail-avoidance technology, which directs aircraft to climb above or descend below contrail-forming conditions, the latest study also identified operational challenges occurring in daily flight operations.

“The results from the trials with DECISIONX, which uses Earth Observation and other meteorological data to power and validate atmospheric modelling, demonstrate how fundamental the use of space is to this global ambition,” said Dr Craig Brown, Director of Investment at the UK Space Agency, which co-funded the 12-airline study. “SATAVIA’s technology could make a significant impact on the voluntary carbon market, boosting opportunities for aviation sector investment in the UK while supporting major industry initiatives against climate change.”

Arnaud Runge, technical officer for the European Space Agency, said his organisation’s co-funding of the programme had helped SATAVIA to engage a larger group of airlines, generating a greater range of data and highlighting how space technologies could assist the air transport industry in progressing its environmental agenda.

Sophia Dunning, Condor’s senior manager for sustainability, said contrail management “offers potential for a much more conscious approach to the impact of daily flight operations on the environment and the climate.

“We are very excited about future developments of the technology in this area.”

Photo: Satavia

Tony Harrington

Correspondent

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While mitigating CO2 emissions from flights through the sale and purchase of carbon offsets or credits has been around for many years, no such market mechanism exists to address the non-CO2 climate impacts from flights, although some carbon offset providers will apply a simple multiplier to the CO2 emissions to account for them. Contrail prevention technology company SATAVIA is now working to develop a methodology concept that would deliver credits for mitigating climate warming caused by aircraft-induced clouds. The methodology has just been approved for progression by carbon and sustainable development standards body Gold Standard, which could pave the way for the future issuance of non-CO2 Certified Mitigation Outcome Units (CMOUs) to provide a credit-based incentive for aircraft operators implementing contrail management.

Aircraft-generated contrails are short-lived climate forcers (SLFCs) that cause surface warming, which may account for over 60% of aviation’s climate impact, around double that of direct CO2 emissions from aircraft, says SATAVIA.

“SLFCs are an important and growing field of climate impact mitigation, pioneered by Gold Standard in 2015,” said Owen Hewlett, Chief Technical Officer at Gold Standard. “It is clear that in order to combat the climate crisis, we need to couple a serious conversation about the volume and necessity of flights with a significant reduction in the impact of flying.”

Cambridge, UK-based SATAVIA has been working with airlines including Etihad to develop a contrail management platform called DECISION:NETZERO that optimises flight plans for contrail prevention, incorporating contrail likelihood forecasts based on atmospheric and climate science. The platform is designed to validate contrail prevention and achieved climate benefit, using atmospheric modelling and observational data. The company is seeking to build a methodology to convert the achieved climate benefit into future carbon equivalent units that can be traded on voluntary carbon exchange platforms.

“SATAVIA’s methodology is an example of a novel activity addressing SLFCs and will provide aircraft operators with a clear incentive to implement contrail management in day-to-day activity, making a tangible reduction of aviation’s climate impact,” said Hewlett.

Approved for progression, SATAVIA is now aiming to get approval from Gold Standard’s Technical Advisory Committee and has ambitions to achieve Design Certification later this year or early 2024. According to SATAVIA, this will then enable the issuance of contrail CMOUs against declared aviation non-CO2 climate impact inventories, so ensuring their use in support of contrail management activity. It stresses CMOUs will be subject to sector-specific rules and restrictions, so limiting their use to in-sector stakeholders, and in parallel, Gold Standard will also develop registry functionality to allow CMOU trading.

SATAVIA says it will seek CMOU recognition from ICAO in respect of the UN agency’s CORSIA offsetting scheme for international aviation, “with the aim of bringing contrail management incentives to the widest possible market.”

Commented the company’s CEO, Dr Adam Durant: “Our practical approach to contrail mitigation offers an incentive for aircraft operators to immediately start cutting their non-CO2 climate footprint, which we hope will drive rapid adoption across the industry. As a software solution incorporating the excellent and decades-mature atmospheric science available to us, contrail management provides the airline sector with an immediate and tangible option to reduce the climate impact of flying.

“With the incentive provided by Gold Standard CMOUs, aviation could reduce its non-CO2 impact by perhaps 50% before 2030. All we need is a willingness to adopt this approach that, importantly, doesn’t require any changes to regulation and could be deployed at scale today.”

SATAVIA has so far worked with Etihad, KLM and KLM Cityhopper, and Emirates, in addition to multiple operator demonstrations supported by the UK-based European Space Agency through the Business Applications programme.

Since starting aircraft operator contrail management trials in 2021, SATAVIA said having now worked with nine airlines, results had shown on average around a 75-tonne CO2-equivalent saving per flight, with a fuel impact of 0.1% on modified flights only.

“This exciting development will supercharge industry progress towards greener flight operations,” said Mariam Musallam Al-Qubaisi, Head of Sustainability and Business Excellence at Etihad Airways. “By implementing small navigational changes to a minority of flights, Etihad can use SATAVIA technology to prevent contrails and generate CMOUs to support new and more sustainable business models.”

Professor Sir Iain Gray of Cranfield University, Chair of the UK’s Jet Zero Council Task & Finish Group on aviation’s non-CO2 effects, commented: “The aviation sector has, and remains, focused on finding ways to cut CO2 emissions but it is also widely understood that aviation has significant non-CO2 impacts, such as contrails. It’s great to see a UK-based SME leading on ways in which to address contrail management and help mitigate this climate-warming effect.”

EU lawmakers believe non-CO2 effects on climate from aviation are at least as important as the impact of CO2 alone. An agreement earlier this year between the European Council, representing EU member states, and the European Parliament on changes to the EU Emissions Trading System provides for the Commission to implement a monitoring, reporting and verification (MRV) system for non-CO2 effects in aviation from 2025. By 2027, the Commission is expected to submit a report based on the MRV and, by 2028, after an impact assessment, make a proposal to address non-CO2 effects.

Photo: SATAVIA/Gold Standard

Christopher Surgenor

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Weather prediction and navigational technology developer SATAVIA is partnering with AirCarbon Exchange (ACX) to support trading of carbon credits generated by SATAVIA’s contrail prevention technology. The company’s atmospheric modelling enables aircraft operators to optimise flight plans for avoiding contrails, which contribute substantially to aviation’s non-CO2 climate impact. The subsequent climate benefit, say the partners, can be converted into tradable carbon credits in a new market they estimate could be worth up to $9 billion at current nominal voluntary carbon pricing, which is forecast to rise tenfold by 2030. A first ACX trade to monetise contrail prevention activity coincided with a number of sustainability initiatives carried out by SATAVIA’s commercial partner Etihad during the week leading up to Earth Day last month that included optimising multiple flight plans for contrail prevention. Etihad undertook research and testing on over 30 flights covering operational efficiencies, as well as testing technology and procedures to reduce carbon emissions. The Abu Dhabi-based carrier also released its sustainability report for 2020-2021 that outlines the impact the airline has had on the environment and details of its Greenliner and Sustainable50 programmes.

Commenting on the new partnership with ACX, SATAVIA CEO Adam Durrant said: “Credits are already available to offset aviation’s direct CO2 emissions but direct emissions only account for about a third of the sector’s climate impact. Generating tradable credits for indirect impacts arising from aircraft contrails is a big step forward in attempts to decarbonise aviation as a sector, creating commercial incentives for operators to enable smarter, greener flying.”

The company describes its DECISIONX:NETZERO platform as a software solution “with immediate applicability and near-term returns”. It adds: “By engaging in contrail prevention activity, eco-conscious operators like Etihad will now be able to generate commercial returns from climate-friendly operations, helping to support commercially sustainable green aviation.”

Launched in 2019, ACX is a global exchange for the voluntary carbon market, with a client base comprising corporate entities, financial traders, carbon project developers and other industry stakeholders.

“Our ground-breaking blockchain architecture is a great fit with SATAVIA’s disruptive tech-led innovation and I look forward to supporting greener aviation with further trades in the months and years to come,” said ACX Managing Director and Co-founder, William Pazos.

The $9 billion carbon market valuation is based, say the partners, on scientific research suggesting aircraft contrails generated up to 1.8 billion tonnes of CO2e in pre-Covid 2019.

“Low-hanging fruit of this magnitude doesn’t come along very often,” commented Pazos.

Etihad’s week-long programme included around 20 commercial flights operating across its network to test SATAVIA’s contrail avoidance technologies as part of the year-long partnership. It also operated dedicated ‘EcoFlights’ involving A350 and Boeing 787 aircraft, including the Etihad Greenliner and the airline’s newest Sustainable50 aircraft, to test a range of flight and engine optimisation initiatives, with trials proving successful to be incorporated into regular scheduled operations.

“The results we develop will add to the body of work and knowledge base we’ve built to support the aviation industry on its journey to decarbonisation,” said Etihad Group CEO Tony Douglas.

According to Etihad’s 2020-2021 Sustainability Report, the group’s carbon emissions fell from around 9.8 million tonnes in 2018 to 4.3 million tonnes in 2020 and 2021, a 56% reduction, largely as a result of the Covid pandemic. Etihad has a target to achieve a 20% reduction in emissions intensity in its passenger fleet by 2025, cut 2019 net emissions by 50% by 2035 and reach net zero emissions by 2050.

Other activities during the reporting period include Etihad becoming the first airline to secure commercial finance based on verified compliance with the UN Sustainable Development Goals and the raising of $1.2 billion in the first sustainability-linked loan tied to ESG targets in global aviation.

“Our sustainability report highlights our insistence on harnessing the opportunities that are available today and commits to continuing to find solutions for the future,” commented Douglas. “Many partners joined us on this journey over the last two years and this report demonstrates the potential we have collectively, with an ambition to set the direction for 2022 and beyond.

“We need to be bold in facing this issue. We need to be decisive. There is no other way forward. That is why we have been insistent that we continue to focus on the question as a long-term strategic priority for our business, spearheaded by the Etihad Greenliner and Sustainable50 programmes.”

Photo: Etihad Boeing 787

Although research is ongoing, it is widely accepted aviation’s contribution to global warming goes well beyond that caused by carbon dioxide emissions alone. One of the main non-CO2 impacts is the net warming effect from the formation of contrails and contrail cirrus caused when aircraft engines emit particulates (soot) at altitude in ice-supersaturated regions. The main culprit is the aromatic content of jet fuel, and fuels with a higher concentration of aromatics and especially naphthalene, a bicyclic aromatic compound, cause higher particulate emissions because aromatics burn slower than other hydrocarbons. Sustainable aviation fuels, on the hand, have negligible concentrations of aromatics because they are hydrotreated. Their use therefore could have beneficial consequences, but they are currently only permitted in blends up to a maximum of 50% with conventional fossil jet fuel so the aromatics issue remains. A report by CE Delft for the Dutch government proposes the aromatic content of jet fuel be monitored or controlled within the proposed ReFuelEU Aviation SAF regulation in such a way that it is decreased to ensure the non-CO2 climate impact of aviation is reduced.

A report on non-CO2 impacts by European aviation agency EASA in 2020 identified lowering the aromatic content of jet fuel as a way of reducing the sector’s climate impact and analysed several policy options but concluded current uncertainty and lack of information about aromatic content was a significant barrier to monitoring the effectiveness of such a policy.

Under current jet fuel standards, the aromatic content is limited to a maximum of 25% by volume and a minimum of 8%. In 2011, a jet fuel study for Lufthansa analysed around 2,000 individual batches of jet fuel. About 75% of the batches had an aromatic content between 16% and 20%, with 15 batches analysed at lower than 8%. From analysis of literature and data supplied by a major fuel supplier, the CE Delft research found that a large share of jet fuel sold in Europe has an aromatic content of 15 to 20% by volume. Other data on batches of Jet A-1 produced in a number of European and North American refineries showed a variety between 8% and 25%, with an average of 18.7% aromatics. This is all within the allowed range as set by jet fuel standards, notes the CE Delft report.

The requirement for a minimum 8% content of aromatics has historically been applied for safety considerations, stemming from the role aromatics play in the swell of sealings in the aircraft fuel system. However, the report found contradicting opinions on this, with several modern aircraft and engine types having sealing materials that do not require aromatics for the swell function, and research into new materials is ongoing.

“Moreover, in practice, aircraft sometimes use fuels with an aromatic content of less than 8%, probably unknowingly,” it adds. “All in all, there is consensus on the requirement for an upper limit of aromatics but there is no consensus in the industry for the necessity of a minimum level aromatics in jet fuel. Other than on financial grounds, there are no clear reasons not to reduce the upper limit. Further research is needed to confirm or deny the role of the minimum content of aromatics for their lubrication purpose in aircraft.”

The CE Delft study carried out interviews with industry experts and parties involved in the production and supply chain of jet fuel. It found a gradual reduction in the upper limit would be a possible way to decrease the aromatic and naphthalene content in jet fuel, as some parties indicated the jet fuel market might experience difficulties if a strict or abrupt reduction of the upper limit was enforced. Because of the financial and time investment this would require by refineries, a reduction of aromatics content might lead to a higher cost of jet fuel, although, suggests the report, this increase could contribute to closing the gap in price difference between sustainable aviation fuel and conventional fossil jet fuel.

As they are conforming to jet fuel standards, from the refinery perspective, there is currently no incentive, financially or legally, to modify the production process to diminish the content of aromatics, sulphur and naphthalene in conventional jet fuel, it points out. Airlines might be interested because jet fuel with lower aromatic content has higher energy density and therefore slightly less jet fuel is needed for flying a given distance, and it also reduces their environmental footprint, but likely it would come at a higher fuel price.

Even if fuel suppliers charged airlines for the higher cost, airlines may choose to refuel at other airports in nearby markets. However, says the report: “If the EU were to put a lower maximum aromatics limit for all EU airports in a regulation, with a proper monitoring, reporting and verifying system, there would be little room to bypass the requirements.”

The study analysed how a new system could be set up to monitor aromatic and naphthalene concentrations in aviation fuels, which would allow for the assessment of the impacts of policies like ReFuelEU Aviation on contrail formation and also provide for better estimates of aviation non-CO2 impacts in general, so “filling the data gap that currently exists”.

Under ReFuelEU Aviation, the European Commission is proposing mandatory supply and use of sustainable aviation fuel. SAF could require new standards for aromatic and sulphur content, even if just to confirm the same standards that kerosene has today, suggests the report.

“Monitoring of aromatic and naphthalene content can be internalised with the reporting of SAF shares by the fuel suppliers,” it says. “This approach involves the lowest possible additional cost for the sector and for authorities to monitor, process data and verify. However, the exact design of such a monitoring and reporting system should follow policy or legal requirements for SAF or a lower aromatic content in jet fuel blends.”

The study also looked at how new aviation fuel specifications to reduce contrail formation could be drawn up in the EU and whether the jet fuel ASTM and DEF standards could be set under EU legislation. The report argues there is no EU or international law that would prevent the EU establishing a new standard for aviation fuel, implemented by either a new body or delegating it to an existing body like EASA, to reduce contrail formation and/or air pollution.

“ReFuelEU Aviation offers a great opportunity to establish a system for monitoring the aromatic content of jet fuel, which will increase our understanding of non-CO2 climate impacts and be a building block for addressing contrail formation,” the lead author of the CE Delft report, Jasper Faber, told GreenAir.

However, Adam Durant, CEO of Satavia, whose company is developing weather prediction and navigational avoidance technology designed to help aircraft operators avoid the risk of causing contrails in the first place, argues that while widely-available sustainable aviation fuels are definitely required to decarbonise aviation, the science linking exhaust emissions soot particles to contrail lifetime is still evolving.

“How long is it going to take to scale SAF production – 10, 20, 30 years, or even longer?” he questions. “Contrails management can be done at full scale within the next two years with adequate support. It is important to separate the two issues as SAF is not going to solve contrails.”

Photo: DLR

Two prominent themes emerged at the 2021 Dubai Airshow: recalibration and decarbonisation. With recovery now underway in the air transport industry, confidence was in abundance, with major orders for passenger and freighter aircraft accompanied by the ubiquitous deployment of the word ‘sustainable’, as the air transport industry zeroed in on net zero, while simultaneously increasing operations post-pandemic, reports Tony Harrington. For the first time outside the United States, Boeing displayed and demonstrated its super-efficient but delayed 777-9 widebody, ordered by major customers including all three big Gulf carriers, Emirates, Qatar Airways and Etihad. The latter announced it was renewing and expanding its Greenliner sustainability programme – currently focused on the airline’s GEnX-powered Boeing 787 aircraft – to include its Rolls-Royce XWB-powered Airbus A350 fleet. Building on its 2020 commitment to achieve net zero by 2050, UAE national airline Etihad revealed during the air show interim targets to reducing emissions intensity and volumes, and signed a number of sustainability-focused agreements.

It announced that by 2025, the carrier would reduce its fleet emissions intensity by 20% and by 2035 it would halve its 2019-equivalent emission volumes, en-route to the net zero 2050 target.

Etihad’s first of five Airbus A350-1000s, which rolled off the production line and into storage prior to the Covid outbreak as the airline restructured its operations, was unveiled at the show in a ‘UAE50’ livery in recognition of the 50th anniversary of the federation of the UAE and Etihad’s net zero by 2050 commitment. Last month, the UAE announced the UAE Net Zero by 2050 Strategic Initiative, making it the first nation in the Middle East to commit to the emissions goal.

Tony Douglas, CEO of Etihad Aviation Group, said “there was no silver bullet, no obvious, single act” that would decarbonise aviation. “It’s going to require the combination and the sum of many different organisations and governments working together for small, incremental improvements,” he said. “Governments and regulators must help the industry to drive innovation for long-term solutions to decarbonising aviation. Support is needed for development of affordable and sufficient supply of sustainable fuels. Optimising flight paths on the busiest routes in the world would prevent untold amounts of CO2 from being pumped into the atmosphere. There is a big opportunity here that doesn’t require any new technology to implement and could be implemented today if there was a will.”

The renewal of the agreement with Boeing and GE will see them exploring opportunities to test new propulsion technologies that lower emissions. The partnership with Airbus establishes a formal framework to collaborate across a number of core areas on Etihad’s A350 fleet to improve environmental performance, specifically the promotion and commercialisation of sustainable aviation fuel, waste and weight management, and the development of data driven analysis. The agreement with Rolls-Royce will look to maximise the potential of the XWB engine as well as targeting the application of electrification technologies and hybrid systems, together with the use of electric motors for commuter aircraft and the emerging urban air mobility sector.

Additionally, Etihad signed MoUs in Dubai to collaborate with UK-based Satavia, which uses data to optimise flight plans and reduce aircraft-generated contrails and CO2, with Tadweer, the Abu Dhabi Waste Management Centre, to jointly explore opportunities to convert commercial, industrial and municipal solid waste into sustainable aviation fuel, and also with The Story Group, to plant mangrove trees in Abu Dhabi’s Jubail Mangrove Park as part of the airline’s carbon offsetting strategy.

Meanwhile, Emirates and GE Aviation also signed a MoU to test fly a GE90-powered 777-300ER with 100% sustainable aviation fuel (SAF) by the end of 2022. John Slattery, CEO of GE Aviation, said the engine manufacturer was committed to developing emission reduction technologies for both in-service and new aircraft, while Emirates COO Adel Al Redha said the partnership was “an important step” towards securing certification of 100% SAF flights.

The airline received its first A380 powered by SAF in December 2020 and, with the support of Swedavia’s Biofuel Incentive Programme, also uplifted 32 tonnes of SAF for its flights from Stockholm earlier that year. Flights from Oslo have also begun operating on SAF under the Norwegian government’s SAF blending mandate policy.

New technologies to improve the sustainable performance of existing aircraft also featured at the Dubai show.

Among them, US-based Universal Hydrogen, which is developing kits to convert conventionally-powered turboprop aircraft to hydrogen-electric propulsion systems, has secured a letter of intent from Acia Aero Leasing for kits to convert 10 ATR-72 aircraft, and options for 20 additional kits for various turboprop types. Universal has developed hydrogen capsules, which can be transported via existing freight networks from hydrogen production facilities direct to airports and loaded into the aircraft they will power.

Lufthansa Technik (LHT) and BASF showcased their Aeroshark surface film, designed to reduce aircraft aerodynamic drag. The product features micro-riblets to replicate the skin of a shark, and initially will be applied to 10 Lufthansa Cargo Boeing 777s from early 2022, reducing carbon emissions by an estimated 11,700 tonnes per year. LHT also signed a MoU with Etihad that will explore digital solutions to further optimise the airline’s technical fleet and operations management, and boost fuel efficiency.

Boeing displayed the latest aircraft in its ecoDemonstrator programme, a Boeing 737-9 on loan from Alaska Airlines, which is being used to evaluate 20 safety and sustainability projects. 

As backdrops to the show, Airbus, Boeing and Embraer all released 20-year forecasts of air travel growth – globally, by region and by segment – with significant but varied predictions of requirements for new aircraft. Airbus estimates that by 2040, 39,000 new-build planes will be needed, 29,700 of them ‘small’ jets such as the narrowbody A220 and A320; 5,300 ‘medium’ A321XLR (extra-long range) narrowbodies or twin-aisle A330neos; and 4,000 large, long-range twins. Boeing goes higher with around 43,000, including 32,660 single-aisle jets, 2,390 regional jets and 7,670 widebodies. Regional specialist Embraer forecasts the need for 10,900 new sub-150 seat aircraft, 8,640 of them jets and 2,260 turboprops. In addition to opportunities to cut operating costs, all cited the need for airlines to decarbonise their operations as one of the key drivers of fleet renewal.

Photo: Dubai Airshow 2021 (© Mark Pilling)

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T&E joins aviation and climate scientists in urging action to reduce warming contrails

16 December 2024 0

Etihad Airways, the national airline of the United Arab Emirates, will mark the second anniversary of its Greenliner programme with a dedicated sustainable flight from London Heathrow to Abu Dhabi on October 23, showcasing a range of initiatives in the air and on the ground that reduce environmental impact, reports Tony Harrington. Using its signature ‘Etihad Greenliner’ aircraft, a themed Boeing 787-10, the airline expects to reduce total emissions of flight EY20 by 72%, and emissions per unit of payload by 56%, compared to the equivalent flight in 2019, at that time operated mainly with Airbus A380s. Among the features of the latest ‘eco flight’ will be a 38% blend of sustainable aviation fuel (SAF) and new technology designed by SATAVIA to minimise climate-warming aircraft contrails. A dedicated page on the Etihad website has been set up to encourage customers to book a journey on the flight and is running a competition offering a free seat.

The Etihad Greenliner programme, a partnership with Boeing and GE, was launched at the Dubai Air Show in 2019 to highlight the importance of industry collaboration in reducing aviation’s emissions. At a joint unveiling with Boeing of the ‘Greenliner’ aircraft livery, Etihad announced that scheduled flights with its entire fleet of Boeing 787-9 and 787-10 aircraft could be used by approved partners for collaborative research of efficiency and sustainability measures in real operating conditions.

Commenting on the October 23 flight, Tony Douglas, CEO of the Etihad Group, said: “This will put into practice all our learnings over the last two years of the Etihad Greenliner programme, which has allowed us to test SAF, eco-friendly products and a range of operational efficiencies, as well as reduce single-use plastic on board and practice optimised flight route planning and continuous descent.”

But he sounded a warning about impediments to achieving net zero emissions aviation.

“We understand that current and near-future technology can only take us and the aviation industry so far,” he said. “We urgently need to see fundamental advances in technology and support from governments and regulators across the world, so we can overcome the current challenges to reaching the industry target of zero emissions by 2050.” 

Among these was the price of SAF, which Douglas told a recent CAPA Live summit was too expensive and needed incentives to encourage airline uptake. “Unless the economics of this can be resolved,” he said, “it clearly isn’t going to be a sustainable part of the solution.”  

The Heathrow – Abu Dhabi flight, which typically takes six hours 50 minutes, will be preceded on October 23 by an aircraft exterior wash, to maximise aerodynamics and efficiency, and a dedicated foam wash for its two GEnX engines, a process developed in partnership with the engine manufacturer, GE. Fuel for the flight will incorporate a 38% blend of undisclosed sustainable product.

Etihad will use new software being developed by UK-based partner SATAVIA to model the formation of contrails, or emitted vapour trails, for the flight, which will be used to optimise routing and help eliminate surface warming generated by aircraft contrails at cruise altitudes.

Through the use of Boeing’s Jeppesen FliteDeck Advisor technology, the pilots will have access to real time data to help maximise the sustainable performance of the aircraft and in collaboration with air navigation service providers, an optimised route will be planned, including the most efficient climb profile from Heathrow, the best path and altitudes for the journey, and a continuous descent to Abu Dhabi.

To further improve fuel efficiency on the flight, Etihad will remove unnecessary weight from the aircraft by reducing the amount of potable water carried, demand for which varies by route and even by time of flight, according to previous research by the airline. Passengers also will be rewarded for flying without checked bags or with lightweight luggage, further reducing aircraft weight through more efficient packing.

On board, lightweight stainless-steel cutlery will be used, as will specially selected catering items including meal trays and crockery, menus will include vegan options, but exclude products including beef and palm oil, which are not produced sustainably. All passengers will receive personal water bottles instead of single use cups, reducing waste, which will be segregated for recycling in Abu Dhabi.

After landing, the aircraft will use single-engine taxi-in and be supported at the terminal by new electric-powered tractors to tow baggage and freight.

Information collected through the aircraft’s sensors will be analysed using tools from another Etihad sustainability partner, GE Digital, and the results added to the airline’s data bank to help pilots and engineers on future flights to recognise patterns of unsustainable activity, and to respond quickly.

In a further initiative to commemorate the special flight, the airline will plant in an Abu Dhabi mangrove plantation one tree for every passenger on the plane, a measure which follows its recent introduction of the CarbonClick programme, through which passengers can purchase offsets to help mitigate their share of flight emissions. The offsets were sourced through the Makame Savannah REDD Project created by Carbon Tanzania and compensate for approximately 80,000 tonnes of CO2, an amount which the airline said would take 100,000 trees one year to consume.

In addition to the special flight, other initiatives have also been used by Etihad this year to help meet a pledge to offset the total emissions generated by the signature Greenliner Dreamliner for the whole of 2021.

Etihad is phasing out its fleet of 19 Boeing 777-300ER passenger aircraft and has indicated that it is highly unlikely to recall all, or possibly any, of its 10 Airbus A380 super jumbos. Alongside its growing fleet of Boeing 787s, Etihad is also introducing more efficient and sustainable Airbus A350-1000 aircraft, as well new Boeing 777-9s.

Photo: Etihad Greenliner