The start of 2023 has been a challenging time for US sustainable aviation fuel startup Alder Fuels as it undergoes changes following the sudden departure of its founder and CEO Bryan Sherbacow. Following a new multimillion-dollar injection of funding from its existing investors, the company has now reorganised its operations, personnel and partnerships, and is focusing its resources on commercial deployment and certification of its Alder Greencrude (AGC) technology. Industry veteran Sherbacow, who the Alder board said had “engaged in questionable financial transactions that benefited him personally”, has been replaced by Acting CEO Tim Obitts. In positive news for the company, Alder has received a Phase 1 Grant Award of $2 million from the US Department of Energy, its third award, to support the engineering design of the company’s first demonstration-scale plant, which is expected to be located in the US Southeast. Investors in Alder include United Airlines and business aviation fuel and services provider Avfuel, who also have offtake purchase agreements in place for 1.5 billion and 1 billion gallons of SAF respectively over 20 years.

In a statement, a bullish Xavier Adserà, Chairman of Alder Fuels and CEO of London-based private equity firm Adequita Capital, commented: “With multiple DOE grants awarded, strong leadership, multimillion-dollar investments, significant strategic partners and a commercial path forward, Alder’s enormous potential is clear. Once commercialised, Alder’s proprietary technology will play a pivotal role in decarbonising and defossilising critical parts of our economy. The Board and its investors are committed to the company’s success.”

The statement added: “To our friends and colleagues whose roles were directly affected by this reorganisation of operations at Alder Fuels, we thank you for your commitment to the company. You executed your work diligently, with a belief that our mission is bigger than any one individual. Without doubt, you have made this company and our culture better, and we are grateful for your time with us.”

Among the casualties of the reorganisation is Chief Sustainability Officer Nancy Young, who has now left the company. Young was previously VP Environmental Affairs for trade association Airlines for America (formerly the Air Transport Association of America) for 14 years. During this period, she served on working groups at the Commercial Aviation Alternative Fuels Initiative and at ICAO, as well as on the Board of the aviation industry’s Air Transport Action Group.

Sherbacow co-founded AltAir Fuels, a retrofitted refinery in Paramount, California, producing renewable diesel and renewable jet fuel, in 2010 and stayed on as Chief Commercial Officer when the company was taken over by World Energy in 2018. The facility was the world’s first commercial-scale renewable jet fuel plant and began supplying regular deliveries in 2015 to United Airlines.

Obitts took up the role of Acting CEO last month, having joined Alder as Chief Legal Officer early last year. He was previously President & CEO of the National Transportation Association, a US trade body made up of over 3,700 companies. “At Alder, we remain focused on a singular goal: to deliver commercial deployment of our proprietary Alder Greencrude technology,” he said following his appointment.

The Alder technology is based on already commercially viable and validated fast pyrolysis in which woody biomass is converted to a green biocrude that can then be co-hydroprocessed with esters and fatty acids (HEFA) within existing refinery infrastructure to produce a sustainable aviation fuel rich in cyclo-paraffins and aromatics. The company says the SAF properties have exceptional energy density, reduced sooting tendency and polymer seal swell, so enabling a 100% blend. Partners involved in developing the technology include Honeywell UOP (another investor in the company), BTG Bioliquids, National Renewable Energy Laboratory, Washington State University, RPD Technologies, Boeing and others.

“At Alder and with our partners, our technology team has worked tirelessly to advance AGC production and hydrotreating from the lab to pilot scale using a rigorous ‘stage gate’ development process,” said Derek Vardon, Chief Technology Officer at Alder. “We simply would not have been able to advance AGC without the support of these technologists and industry-leading experts.”

Last October, Alder selected BTG’s proprietary fast pyrolysis technology for its first AGC processing facility at the so-far undetermined site in the US Southeast. BTG  develops production plants through its engineering, procurement and construction partner, TechnipEnergies. Fast pyrolysis bio-oil conversion of Alder’s feedstock has been completed at both BTG pilot and demonstration scale plants in the Netherlands, which has been shipped back to Alder’s laboratory and will be used for ASTM certification purposes.

As a result of a long-term, exclusive contract signed last September, Enviva will supply up to 750,000 tonnes per year of sustainably sourced woody biomass to Alder’s AGC facility when commercial production starts. Enviva says its feedstock adheres to the US Environmental Protection Agency’s Renewable Fuel Standard and the two companies have committed to gaining sustainability certification under the Roundtable on Sustainable Biomaterials standard.

Alder is currently pursuing ASTM certification, a critical next step for the company as its technology is not among the seven technology pathways so far approved as a drop-in, alternative jet fuel. “The preliminary datasets related to fuel properties are encouraging,” a company spokesperson told GreenAir. “They suggest we may be able to enter the so-called ‘Fast Track’ approach to certification, which can take 12-18 months and would be significantly faster than the standard path that can take years. We haven’t received formal approval as yet but we have been in discussions and are hopeful it will come this year. We are confident the technology works.

“It is important to note that even without ASTM certification, AGC can be used to make renewable diesel and marine fuel, as well as green chemicals.”

Five of the pathways that have been approved so far under the ASTM D4054 process are required to be blended with petroleum-based jet fuel up to a 50% maximum level, with the other two requiring a maximum 10% level. The blend percentage for each concept that goes through the D4054 Fast Track is currently limited to 10%.

An attractive feature of the Alder Greencrude product is that as a result of pyrolysis, it retains aromatics that are necessary for seal swell in jet engines. A major reason for the 50% maximum blend limit in the present approved pathways is that the technologies employed produce SAF with no aromatic content. To achieve a 100% sustainable aviation fuel therefore requires an additional synthetic aromatic kerosene content and so the Alder product with its cyclo-paraffins has a potential distinct advantage over other SAFs, while also avoiding some of the downsides of aromatics, such as the generation of excess particulates.

“In theory, we could make a 100% SAF but we’re not pursuing it yet as ASTM has not finalised how they are going to qualify 100% SAF,” said the spokesperson. “We are looking at the Fast Track process and will hopefully get certification within 18 months. Once we have it, we’ll decide on the next level of certification, whether it’s 100% SAF or we look for a higher blending level.”

With discussions still ongoing with states and counties on the exact location for the demonstration-scale plant, the company is not yet ready to disclose when construction will start and does not expect completion within the next two years. The facility will be rated to process 120 dry tonnes per day of forest residuals and produce 3 million gallons per year of liquid hydrocarbon biofuel, of which 2 million gallons will be SAF.

“We are still focused on project development and AGC pilot testing to inform engineering for commercial-scale production. We will have more to share on our revised delivery timeline in the coming months,” he reported. “The focus, for now, is resolutely on achieving key technical milestones that further de-risk our production process and get us to the next stage of growth.”

Photo: United Airlines

Christopher Surgenor

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The unprecedented heatwave sweeping the UK during the 2022 Farnborough International Airshow was a timely, if unwelcome, prod to the aviation sector that it must continue raising its game in the collective fight to mitigate the growing impact of global warming. Established and emerging aerospace players, from Airbus to ZeroAvia, used the biggest air show since the start of the pandemic to promote and progress deals, partnerships and initiatives designed to help deliver net zero emissions by 2050. In addition to more than 300 orders for new-technology aircraft, Farnborough showcased a range of developments on new propulsion systems and fuels, the growing trend to convert fossil-fuelled aircraft to zero emission power and continued strong growth in the urban air mobility sector, reports Tony Harrington. As countries met in Montreal to discuss a long-term target to reduce emissions from international aviation, the UK government released at the air show its eagerly-awaited Jet Zero Strategy to decarbonise the British aviation sector.

Having recently unveiled plans to use an A380 superjumbo as a testbed for its ZEROe hydrogen propulsion programme, Airbus announced it would convert a second A380, this time to be used in a collaboration with engine manufacturer CFM International to test new open-architecture powerplants. This engine technology, known as RISE (Revolutionary Innovation for Sustainable Engines), features large external fans which are expected to drive significant operating efficiencies and cut emissions by 20%.

Airbus UpNext, a subsidiary of the airframer, also announced a partnership with the German Aerospace Center (DLR) to study contrails created by hydrogen-powered engines. Through a new project called Blue Condor, two modified Arcus gliders will be deployed, one powered by a conventional kerosene combustion engine, the other hydrogen combustion. A chase aircraft will follow each of these craft to assess and compare their contrails at high altitude, in what will be the first in-flight tests by Airbus using a hydrogen engine.

To further support its hydrogen ambitions, Airbus has invested an undisclosed amount in Hy24, described as the world’s largest clean hydrogen infrastructure investment fund, focused on supporting large-scale green hydrogen infrastructure projects. “Since 2020, Airbus has partnered with numerous airlines, airports, energy providers and industry partners to develop a stepped approach to global hydrogen availability,” said Karine Guenan, VP ZEROe Ecosystem, Airbus. “Joining a fund of this magnitude demonstrates Airbus’ continuously active role in infrastructure investments for the production, storage and distribution of clean hydrogen worldwide.” 

Rolls-Royce and European low-cost airline easyJet also announced a hydrogen propulsion programme, the H2Zero Partnership, to jointly pioneer the development of hydrogen combustion engine technology suitable for a range of aircraft, including narrowbody airliners, from the mid-2030s. This collaboration, which combines Rolls-Royce’s engine expertise and easyJet’s operational experience, will start later this year with engine tests on the ground and ambitions by both companies to also progress to flight tests.

“In order to achieve net zero by 2050, we have always said that radical action is needed to address aviation’s climate impact,” said Johan Lundgren, CEO of easyJet. “The technology that emerges from this programme has the potential to power easyJet-size aircraft, which is why we will also be making a multi-million-pound investment into this programme. In order to achieve decarbonisation at scale, progress on the development of zero-emission technology for narrowbody aircraft is crucial. Together with Rolls-Royce, we look forward to leading the industry to tackle this challenge head-on.”

Boeing, which announced more than 200 aircraft orders at the show, has become a founding member of the University of Sheffield Energy Innovation Centre to explore various methods of producing sustainable aviation fuel, and bringing it to market. During the air show, the aircraft OEM revealed it was advancing its partnership with the University of Cambridge on the Aviation Impact Accelerator (AIA), an international group of practitioners and academics convened by the university. AIA develops interactive evidence-based models, simulations and visualisation tools for decision-makers and the wider engaged public to understand the pathways to net zero flight. The outcomes and key learnings will eventually be integrated into Boeing’s Cascade data modelling tool, which provides real-time visualisation of carbon emission reductions in aviation, and also announced during the show. The model assesses the full lifecycle impacts of renewable energy by accounting for the emissions required to produce, distribute and use alternative energy carriers such as hydrogen, electricity and SAF. Boeing said it plans to utilise the tool with airline operators, industry partners and policymakers to inform when, where and how different fuel sources intersect with new airplane designs.

The company also expanded a long-standing collaboration with Japan’s Mitsubishi Heavy industries to study electric and hydrogen propulsion, development of green hydrogen, new feedstocks and technologies for development of SAF, carbon capture and conversion, sustainable materials and new aircraft design concepts. As well, Boeing announced a $50 million investment in AEI HorizonX, a partnership it established with private equity group AE Industrial Partners to support transformative aerospace technologies.

“In order for the aviation industry to meet its net zero carbon emissions commitment by 2050 it will take all of us collaborating and investing in scientific research and testing,” said Boeing’s VP of Global Sustainability Policy, Brian Moran.

Boeing also announced a new partnership with Alder Fuels to expand production of SAF around the world. Using Boeing aircraft, the companies will test and qualify Alder-derived SAF, advance policies to expedite aviation’s energy transition.

Meanwhile, Virgin Atlantic, Corendon Dutch Airlines and Albawings have selected Boeing’s Jeppesen FliteDeck Advisor to optimise operational efficiency and reduce fuel consumption across their fleets of Boeing aircraft. During a three-month trial on its 787 Dreamliners, Virgin Atlantic found the digital solution delivered cruise fuel savings of 1.7%, saving around 1,900kg of CO2 per flight.

Hydrogen propulsion pioneer ZeroAvia secured an additional $30 million from new investors including Barclays Sustainable Impact Capital, NEOM, a sustainable regional development in Saudi Arabia, and the impact technology fund AENU, as well as additional capital from International Airlines Group, an existing investor and parent of airlines including British Airways, Iberia, Aer Lingus, Vueling and LEVEL. “Our new investors are each looking at our journey through a different lens,” said Val Miftakhov, founder and CEO of ZeroAvia, “but all energised by our mission to enable zero-emission flight using hydrogen-electric engines.”

ZeroAvia, Universal Hydrogen and Ampaire announced during the air show a total of 55 firm orders for kits to convert commuter or turboprop aircraft from fossil fuels to zero-emission electric or hydrogen propulsion, while Swiss aero-battery manufacturer H55 launched a partnership with Canadian training group CAE and Piper Aircraft to convert to battery-electric power two-thirds of CAE’s fleet of Piper Archer training aircraft. Ampaire also flagged in excess of 200 orders on the horizon for its Eco Caravan and Eco Otter aircraft, re-engined variants of the Cessna Caravan and De Havilland Twin Otter regional aircraft.

GKN Aerospace revealed during the show that advances in fuel cell technology could enable hydrogen-electric propulsion to be scaled up more quickly than previously thought. The company had assumed that hydrogen propulsion was easiest to introduce for aircraft seating around 19 passengers, but now believes the use of cryogenic cooling technology can expedite deployment of the technology to power aircraft seating 96 or even more passengers, and reducing both CO2 and non-CO2 emissions.

Norway’s Widerøe Zero, the sustainability arm of regional airline Widerøe, signed a MoU with Embraer to help develop the airframer’s new Energia family of zero emission aircraft, with four variants ranging from 19 to 50 seats, while Collins Aerospace has completed the preliminary design of a 1-megawatt motor and controller to power a hybrid-electric demonstrator aircraft for the engine manufacturer Pratt & Whitney Canada.

Collins and Pratt & Whitney also launched a new electric propulsion concept, the Scaleable Turboelectric Powertrain Technology demonstrator (STEP-tech), to power novel aircraft including high-speed electric vertical take-off or landing craft (eVTOL), unmanned aerial vehicles (UAV) and small-to-medium commercial aircraft, while new deals, developments and partnerships were announced in the eVTOL segment by companies including Germany’s Lilium, Embraer’s Eve, UK-based Vertical Aerospace, French start-up Ascendance Flight Technologies and a tie up between Rolls Royce and Hyundai Motor Group’s air taxi division, Supernal.

GE Aviation announced a milestone for its own electric engine programme, conducting the world’s first test of a hybrid-electric propulsion system in simulated high-altitude conditions. Using NASA’s Electric Aircraft Testbed (NEAT) in Sandusky, Ohio, GE assessed a pair of hybrid electric systems, one to simulate an aircraft’s left engine, the other its right engine, in conditions expected when flying at 45,000 feet. The test simulated the electrical loads needed to optimise engine performance, while propelling and powering an aircraft at that altitude.   

Mohamed Ali, VP and GM of Engineering for GE Aerospace, said: “We’re making aviation history by developing the technology to help make hybrid electric flight possible for everyday commercial air travel. We just passed a key milestone by successfully concluding the world’s first test of a high power, high voltage electric system at altitude conditions. This is one of many milestones in our journey with NASA towards demonstrating a hybrid electric aircraft engine system for a more sustainable future of flight.”

A small Spanish airline, AlbaStar, was identified at Farnborough as the European launch customer for the US-made WheelTug electric taxiing system, which enables aircraft to be manoeuvred around airports without using external tractors or their own engines. Using a small electric motor installed within the nosewheel, pilots can control all ground movements by their aircraft, including reversing from airport aerobridges. AlbaStar, which operates six Boeing 737 jets, estimates that in a year the WheelTug system could eliminate 1 million kilograms of CO2 and nitrogen oxide emissions from the airline’s operations. The WheelTug system is due to be introduced into service in mid-2023.

Image (Embraer): Norwegian airline Widerøe has signed a MoU with Embraer to help develop the airframer’s new Energia family of zero emission aircraft

United Airlines Ventures (UAV) has announced an investment in New York-based Dimensional Energy, the airline group’s fourth move into sustainable aviation fuel production, and its first into power-to-liquid (PtL) technology, in which carbon dioxide is transformed into SAF. United has also agreed to purchase at least 300 million gallons of SAF from Dimensional over 20 years, adding to multiple existing agreements that the airline claims add up to the biggest collective SAF commitment by any airline. The deal caps off a flurry of fresh SAF announcements across the US, from Hawaii to New York, as the air transport industry intensifies efforts to cut its carbon emissions. A project involving Delta Air Lines and Neste is now delivering SAF through fuel pipeline systems direct to New York LaGuardia. Meanwhile, there have been renewed calls from across the US aviation sector for greater government incentives to expedite and increase the availability of affordable supplies of SAF, reports Tony Harrington.

Dimensional Energy converts carbon dioxide and water into usable ingredients for the Fischer-Tropsch (FT) process that can turn those elements and others into liquid fuels. While this system has been widely used to create fossil fuels, Dimensional claims it will be one of the first to produce sustainable aviation fuels from the process. Last year, the company’s activities attracted funding from climate technology investor Elemental Excelerator, through which it was introduced to United, which wants to cut emissions directly rather than through offsets.

“Sometimes you have to look to the past to solve new problems and we recognise that decarbonising air travel is going to require combining proven technologies, such as Fischer-Tropsch, with the latest advances in science and engineering,” said United Airlines Ventures President Michael Leskinen. “As we grow our portfolio of companies like Dimensional, we are creating opportunities to scale these early-stage technologies and achieve United’s commitment to carbon neutrality by 2050, without the use of traditional carbon offsets.”

UAV has already invested in SAF producer Alder Fuels, from which United Airlines will acquire up to 1.5 billion gallons of SAF, while United itself has bought into Fulcrum Bioenergy, together with an option to buy up to 900 million gallons of SAF. As well, UAV recently invested in Cemvita Factory, a US-based synthetic biology company which is planning SAF production.

Dimensional says it can transform carbon dioxide from sources including direct emissions from industrial sites, direct air capture and biological paths including fermentation and biomass gasification, providing United with some protection from the constraints of feedstock availability affecting other biofuel pathways. Last year, in Tucson, Arizona, the company began constructing a CO2-to-fuels facility, part-powered by locally-produced renewable energy, and expects to begin operating next month.

”United’s support of sustainable aviation fuel made from captured emissions is an important step in the aviation industry’s pursuit of carbon neutrality,” said Jason Salfi, CEO and joint founder of Dimensional Energy. “We envision a world run on truly conflict-free energy that can scale to meet the global demand for hydrocarbon fuels and feedstocks.”

Meanwhile, competitor Delta Air Lines was one of four participants in a milestone project to deliver the first supplies of SAF to New York’s LaGuardia Airport using existing infrastructure. The fuel was processed in Texas by waste-to-SAF producer Neste, then transported via the Colonial and Buckeye pipeline systems to the airport to power a Delta flight. “SAF is the most effective tool we have to decarbonise our industry,” said Delta’s Chief Sustainability Officer, Pamela Fletcher. “These efforts show how existing infrastructure can be used to transport SAF to east coast airports and drive down emissions, a critical step as we move toward a more sustainable future for air travel.”   

The fuel was loaded by Neste into the Colonial Pipeline and pumped almost 1,500 miles to New Jersey, where it was transferred into the Buckeye Pipeline which feeds LaGuardia Airport. “The US east coast is home to some of the USA’s busiest airports and the vast majority of them get their fuel from the Colonial Pipeline system and, in New York, the Buckeye Pipeline system,” added Chris Cooper, Neste’s VP of Renewable Aviation in the Americas. “What we’re doing here is showing that just around the corner is a future where passengers at Atlanta’s Hartsfield-Jackson, up to LaGuardia, JFK (Kennedy Airport) and EWR (Newark Airport) can board a plane flying on SAF.”

Delta and Neste have called for additional government policy settings and supply chain incentives in the US to increase production pf SAF, while driving down its cost. Announcing the LaGuardia initiative, they said: “A SAF Blender’s Tax Credit, for example, that is technology and raw material-neutral, will even the playing field between SAF and fossil jet fuel. At the state level, a Low Carbon Fuel Standard with voluntary opt-in provisions for SAF will provide a policy framework with a proven track record to incentivise SAF production and speed the development of cleaner infrastructure, supporting healthier environments for our communities.”

In Los Angeles, alongside the IX Summit of the Americas, at a roundtable event they hosted on sustainable air transport, industry body IATA and Boeing also ramped up pressure on governments to support SAF production with incentives.

”To reach the industry’s net zero goal, governmental support is critical to developing policies that efficiently accelerate the commercial production and deployment of SAF,” said Peter Cerdá, IATA’s Regional VP for the Americas.

Landon Loomis, Boeing’s VP Latin America, Caribbean and Global Policy, added: “The message from the experts at the roundtable is clear. In addition to a sector-wide partnership, it takes policy commitments, technology deployment and infrastructure efficiency improvements to achieve the industry’s commitment to reach decarbonisation by mid-century.”

Corresponding with the event, Boeing and seven airlines – Aeromexico, Alaska Airlines, American Airlines, COPA Airlines, Delta, United and WestJet – collectively bought 100,000 gallons of SAF (379,000 litres) from World Energy to part-power flights from Los Angeles International Airport, collectively cutting their CO2 emissions by around 472,000 pounds (214.3 tonnes).

In a message to the roundtable, John Kerry, US Special Presidential Envoy for Climate, said: “Reducing emissions from hard to decarbonise sectors like aviation is essential to tackling climate change. I am encouraged by the commitment of airlines worldwide to scale up the use of sustainable aviation fuels, which have the potential to not only significantly reduce emissions in-sector but also to provide economic opportunity.”

As part of its 2022 ecoDemonstrator programme, Boeing will fly one of its own 777-200ER aircraft using a 30/70 SAF blend for all test flights. During the next six months of flight and ground tests, Boeing will evaluate around 30 new technologies aimed at improving sustainability and safety for the aerospace industry, including a water conservation system to reduce aircraft weight and fuel, and technologies to improve operational efficiency.

Separately in Honolulu, Hawaiian Airlines announced a partnership with Par Hawaii, one of the state’s largest energy providers, to explore the viability of developing SAF in the islands from sustainable crops, while in Houston, Texas, renewable energy start-up No Carbon Air announced plans to produce sustainable aviation fuel, hydrogen fuel, and other green energy sources through Fischer-Tropsch conversion of landfill materials including municipal solid waste, hazardous materials, tyres, waste coal, sludges and other waste streams. The company’s CEO, Bill Smith, said the waste, once converted to synthetic gas, would be processed through an FT system capable of producing 3,000 gallons of sustainable jet fuel per day, or 1 million gallons per year.

Photo: United Airlines

United Airlines has operated the first-ever passenger flight with an engine using 100% sustainable aviation fuel. In a partnership with Boeing, CFM International, Virent and World Energy, yesterday’s flight of a new Boeing 737 MAX 8 from Chicago O’Hare to Washington DC’s Reagan National Airport carried 100 passengers. Commercial passenger flights are currently permitted to fly with a maximum of only 50% SAF in their engines but United and their partners received special authorisation from the FAA for the one-off demonstration flight because of the use of Virent’s synthetic aromatic kerosene (SAK) in the fuel blend, which was first used in a United test flight in October. The airline has also announced new corporate participants in its Eco-Skies Alliance corporate programme launched in April this year that has now collectively contributed towards the purchase of more than 7 million gallons of SAF. United claims its SAF purchase commitments are nearly twice the size of those by the rest of the global airline industry combined.

“We continue to lead from the front when it comes to climate change action,” said United CEO Scott Kirby, a passenger on the ORD-DCA flight. “Today’s SAF flight is not only a significant milestone for efforts to decarbonise our industry, but when combined with the surge in commitments to produce and purchase alternative fuels, we’re demonstrating the scalable and impactful way companies can join together and play a role in addressing the biggest challenge of our lifetimes.”

An important reason for the 50% maximum permitted SAF use in commercial flights is the absence of aromatic compounds from the HEFA-based SAF in use today. The minimum aromatic content in conventional jet kerosene is about 8% on average and in common jet engines the aromatic content encourages the seals to swell, so providing more protection from leakage. When operating with SAF, the lack of aromatics can be overcome by adding them to the fuel or blending it with conventional jet fuel, although concentrations of aromatics should be minimised to reduce carbon emissions.

The SAF used for the United test flight in October, and for yesterday’s passenger flight, was a mix of Virent’s BioForm SAK and World Energy’s HEFA synthetic paraffinic kerosene (SPK). This accounts for the lower aromatic content in the SPK made through HEFA pathways, while still enabling a blend that is 0% fossil fuel-derived and a 100% drop-in ready with no aircraft or engine modification required, said United.

SAK is produced at Virent’s demonstration plant in Madison, Wisconsin, using corn dextrose from Iowa, and the company is targeting a greater than 50% reduction in lifecycle GHG emissions. Virent’s parent company, Marathon Petroleum, provided testing, blending and transportation of the 100% SAF for the United flights. Virent has also developed data from engine testing that shows a SAK/HEFA blend is cleaner burning and has lower particulate matter emissions than conventional jet fuels.

“Showing Virent’s BioForm SAK enables a 100% SAF that meets current jet fuel specifications is a big step, as it demonstrates that SAF can be a reality without the need to make significant changes to the current aviation fleet and infrastructure,” said Dave Kettner, Virent President and General Counsel, after the October test flight. “Virent’s proprietary technology demonstrates that SAF can be 100% renewable and 100% compatible with our current aviation fleet and infrastructure.”

United recently agreed to purchase 1.5 billion gallons of SAF from startup Alder Fuels, which the airline says is enough to fly more than 57 million passengers. Alder Fuels, headed by former World Energy CCO Bryan Sherbacow, recently announced a strategic alliance with government of Colombia to source biomass feedstock for conversion into sustainable low-carbon crude used for producing SAF.

The airline is also an investor in Fulcrum BioEnergy, in which it has an option to purchase up to 900 million gallons of SAF.

United has nearly 30 participants in its Eco-Skies Alliance programme, including 12 new participants such as Maersk, Meta, Microsoft, Salesforce and Visa. The collective purchase this year of more than 7 million gallons of SAF, with 80% GHG emissions reductions on a lifecycle basis, is enough to eliminate around 66,000 tonnes of CO2e emissions, or enough to fly passengers more than 460 million miles, says United. To build transparency and enable certified SAF emission reductions for its corporate customers, the airline recently partnered with Microsoft, Air bp and the Roundtable on Sustainable Biomaterials in a first-ever book and claim pilot (see article).

Photo: Fuelling United’s 100% SAF flight

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United Airlines and Honeywell have announced a joint multimillion-dollar investment in Alder Fuels, a new cleantech venture headed by Bryan Sherbacow, founder of AltAir Fuels (now World Energy), the world’s first commercial sustainable aviation fuel (SAF) producer. United has also agreed to purchase 1.5 billion gallons of SAF over 20 years, the largest publicly announced SAF agreement to date, reports Susan van Dyk. The airline says the purchase is one-and-a-half times the size of the rest of the world’s airlines’ publicly announced SAF commitments combined. Alder claims it will be pioneering first-of-its-kind technologies to produce SAF at scale by converting abundant biomass, such as forest and crop waste, into sustainable low-carbon, drop-in replacement crude oil that can be used to produce aviation fuel. When coupled with Honeywell’s Ecofining process, the start-up says the technologies could have the ability to produce a carbon-negative fuel across the full lifecycle at a specification with today’s jet fuel.

United has pledged to reduce 100% of its greenhouse gas emissions by 2050 through large investments in SAF production, carbon capture and sequestration, and electric aircraft. It was the first airline to use SAF in regular operations on a continuous basis. Since then, the carrier has purchased more SAF than any other airline and now with this agreement has more than 70% of the airline industry’s publicly announced SAF commitments.

“Since announcing our 100% green commitment in 2020, United has stayed focused on decarbonising without relying on the use of traditional carbon offsets,” said United CEO Scott Kirby. “Part of that commitment means increasing SAF usage and availability since it’s the fastest way to reduce emissions across our fleet. However, to scale SAF as quickly as necessary, we need to look beyond existing solutions and invest in research and development for new pathways like the one Alder is developing.”

United made headlines in 2015 by investing $30 million in Fulcrum Bioenergy, a developer of SAF production from municipal solid waste, and signing, at the time, the largest offtake agreement for SAF. In 2020, United became the first airline to announce a commitment to invest in carbon capture and sequestration and has since followed with investments in electric vertical takeoff and landing aircraft and 19-seat electric aircraft that have the potential to fly customers up to 250 miles before the decade’s end.

To advance its goals, in June 2021, United formed United Airlines Ventures, a venture fund that focuses on startups, upcoming technologies and sustainability concepts that will complement United’s goal of net zero emissions by 2050. The joint investment with Honeywell in Alder Fuels is the latest from United Airlines Ventures and continues what the the company describes as a commitment to achieve carbon neutrality by 2050 by tackling emissions at their source and continuing and accelerating development and investment in clean technologies.

Back in 2008, Honeywell’s UOP process technology played a pioneering role in the first-ever commercial airliner to fly using biofuel from second generation, renewable feedstocks. Made from the oil of jatropha plants, a 50/50 blend was used to power an engine of an Air New Zealand Boeing 747-400 during a test flight.

Honeywell will use its Ecofining process to partner with Alder to commercialise its technology, which was jointly developed with Eni. UOP currently has licensed 20 Ecofining units in nine countries around the world, processing 12 different types of renewable feedstocks.

“Our work with United and Alder on this new technology will help transform the industry and support the growth of a zero-carbon economy,” said Darius Adamczyk, Honeywell’s CEO. 

Currently, all commercial SAF volumes are produced from fats, oils and greases, a costly feedstock with limited availability to produce SAF at required scale. Shifting to other types of low-cost, low-carbon feedstocks that are available in significant quantities is considered critical to large-scale SAF volumes.

Little information, other than that it is a pyrolysis-type technology, is currently available on the specific technology that Alder Fuels will use. This type of technology produces a liquid intermediate that can be further upgraded into finished fuels such as SAF. It is in the upgrading process that Honeywell’s Ecofining technology and their advanced expertise in hydrotreating will become crucial to produce drop-in fuels such as SAF. Alder Fuels also envisages the suitability of the ‘green’ crude oil to be converted by the global refinery industry with existing equipment and infrastructure. Commercialisation is expected by 2025.

The new company’s President and CEO, Bryan Sherbacow, is a veteran in the industry with over 15 years’ experience in the development of low carbon fuels. He was responsible for the first commercialisation of SAF production as co-founder of AltAir Fuels in 2009, the world’s first refinery designed to produce SAF. Commissioned in January 2016, AltAir Paramount converted a petroleum refinery to the production of SAF, renewable diesel, naphtha and propane. Sherbacow negotiated the aviation industry’s first commercial contracts for SAF with United Airlines, KLM and World Fuel Services. Additionally, he executed the first contract for operational use of renewable diesel fuel by the US Navy. Subsequent contracts include with Gulfstream, Boeing, UPS and Amazon. In March 2018, he facilitated the acquisition by World Energy of AltAir and the Paramount refinery assets. Formerly Chief Commercial Officer of World Energy, Sherbacow will continue as senior advisor to the CEO of World Energy, according to his LinkedIn profile.

“Aviation poses one of the greatest technology challenges for addressing climate change and SAF has demonstrated the greatest potential. However, there is insufficient raw material to meet demand,” he said. “Alder’s technology revolutionises SAF production by enabling use of widely available, low-cost and low-carbon feedstock. The industry is now a major step closer to using 100% SAF with our drop-in fuel that accelerates the global transition to a zero-carbon economy.”

According to the US Department of Energy (DOE), US forestry residues and agricultural residues alone could provide enough biomass energy to generate more than 17 billion gallons of jet fuel and displace 75% of US aviation fuel consumption. If the nation was to broadly adopt regenerative agricultural practices, which capture more carbon in healthier soil compared to traditional methods, the US could generate an additional seven billion gallons of SAF, which would completely replace its current fossil jet fuel consumption. Alder’s technology and demand for its fuel from the aviation industry could create a large new market for biomass from regenerative practices.

Photo: United Airlines

Susan van Dyk

GreenAir Correspondent

www.svdconsulting.ca

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