Alternatives to traditional aviation fuel are gaining momentum, whether they take the form of biofuels or other solutions that reduce fuel consumption in some way. Meanwhile, co-operation between governments, academia and industry is increasing, as it is recognised that every little helps, as Megan Ramsay explains
According to the Intergovernmental Panel on Climate Change (IPCC), aviation accounts for approximately 2% of global human-made CO2 emissions, international aviation being responsible for approximately 1.3%. The most recent estimates by the International Civil Aviation Organization (ICAO) anticipate that aviation fuel consumption will increase by a factor of between 2.8 and 3.9 by 2040, underpinned by the growth of the sector.
However, an ICAO spokesperson notes: “Improvements in aircraft technology, infrastructure and operations should keep this growth toward the lower end of the estimate. It means that any action taken to limit the environmental impact of aviation now will allow the sector to grow on an environmentally sustainable footing, hence the importance of sustainable alternative fuels.”
There is, of course, a flip side to the importance of environmental awareness. The ICAO spokesperson points out: “Global air transport connectivity sustains socio-economic development and sustainable alternative fuels support a number of the United Nations Sustainable Development Goals (UN SDGs). From access to clean energy, to the end of poverty and social and inclusive growth, sustainable alternative fuels for aviation show a number of co-benefits that extend their impact beyond the environment.
“Last but not least, one of the key legacies of the Paris Agreement is creating a paradigm shift for action, where every drop of fuel counts. ICAO’s holistic environmental strategy, underpinned by the organisation’s aspirational goals for international aviation CO2 emissions, is a reflection of this paradigm shift.”
Keeping emissions down
ICAO’s Committee on Aviation Environmental Protection (CAEP), comprising 170 international experts, unanimously recommended the organisation’s new CO2 emissions standard in February, paving the way for its adoption by the UN agency’s 36-state Governing Council.
“The goal of this process is ultimately to ensure that when the next generation of aircraft types enter service, there will be guaranteed reductions in international CO2 emissions,” emphasised Olumuyiwa Benard Aliu, president of the ICAO Council. “Our sector presently accounts for under 2% of the world’s annual CO2 emissions, but we also recognise that the projected doubling of global passengers and flights by 2030 must be managed responsibly and sustainably.”
The new standard would apply to new aircraft designs as of 2020 – but also to deliveries of current in-production types from 2023, with a cut-off date of 2028 for production of aircraft that do not comply with the standard. CO2 reductions could arise from various innovations, whether structural, aerodynamic or propulsion-based, ICAO acknowledged.
The organisation said that while the standard covers all sizes and types of planes, it will be “especially stringent where it will have the greatest impact: for larger aircraft. Operations of aircraft weighing over 60 tonnes account for more than 90% of international aviation emissions. They also have access to the broadest range of emissions reduction technologies, which the standard recognises.”
US-based aircraft manufacturer Boeing voiced its support for the standard, saying: “This agreement represents real progress beyond the substantial industry achievements already made to reduce aviation emissions, with more steps ahead. The new standard is ambitious and will become part of the certification process applied to every airplane before delivery based on the ICAO schedule.
“Our new commercial airplanes have been designed to meet and even exceed challenging emission requirements. The 787 Dreamliner family reduces fuel use and CO2 emissions by 20 to 25% compared to airplanes it replaces. The new 737 MAX, with first delivery expected in 2017, will reduce fuel use and emissions by 20% compared to the original Next-Generation 737. The 777X, with first delivery expected in 2020, will be the world’s largest and most fuel-efficient twin-engine jet. For other current or future models, we will make product development decisions based on a range of factors, including cost, certification requirements and market demand.”
Different approaches
Earlier this year, low-cost carrier easyJet revealed that it was working on designs for a hybrid aircraft that would use a zero-emissions hydrogen fuel cell stowed in the plane’s hold to power operations on the ground. The airline believes the design could save around 50,000 tonnes of fuel a year, and reduce CO2 emissions concurrently. It is aiming to cut those emissions by 7% by 2020.
Inspiration for the project came from students at Cranfield University who were asked to develop ideas for what air travel might look like in 20 years’ time, as part of a competition to celebrate easyJet’s 20th birthday in November 2015. Other ideas included dynamic wings which change shape in flight, a super-efficient ‘shark skin’ coating to reduce surface drag and, in the cabin, ultra-lightweight seats carbon fibre seats incorporating wireless phone and tablet charging panels.
The hybrid system allows energy to be captured as the aircraft brakes on landing, charging lightweight batteries when the aircraft is on the ground – much like the Kinetic Energy Recovery System (KERS) found in Formula 1 cars, easyJet explains. The aircraft can then use this energy – for example when taxiing – instead of its jet engines.
“Due to the high frequency and short sector lengths of easyJet’s operations, around 4% of the airline’s total fuel consumed annually is used when the airline’s aircraft are taxiing,” the carrier outlines. “easyJet’s aircraft average 20 minutes of taxi time per flight – the equivalent of around 4 million miles a year – akin to travelling to the moon and back eight times.”
Each hybrid aircraft would have motors in its main wheels and pilots would be able to control its speed, direction and braking during taxi operations, reducing (or even removing) the need for tugs to manoeuvre aircraft in and out of stands, making operations more efficient and cutting turnaround times. The only waste product produced by the system is clean water, which could be used to refill the aircraft’s water system during the flight.
easyJet head of engineering Ian Davies comments: “The hybrid plane concept … is both a vision of the future and a challenge to our partners and suppliers to continue to push the boundaries towards reducing our carbon emissions. It’s also a great example of the benefits of our strategic relationship with Cranfield University.”
easyJet and Cranfield University signed a three-year strategic partnership agreement last year to share innovation and knowledge. The low-cost carrier will now work with its industry partners and suppliers with a view to running trials of the hybrid system later this year.
easyJet operates a fleet of over 240 A319s and A320s with an average age of just six years. The airline will start taking delivery of A320neo aircraft from June 2017 and the new aircraft will be 13 15% more fuel-efficient than the aircraft they are replacing.
Elsewhere, United Airlines launched regular scheduled flights using sustainable biofuel in March. The airline noted that it is the first US carrier to use the alternative fuel on a commercial scale on regular flights rather than on a temporary basis. “The launch marks a significant milestone in the commercial aviation industry by moving beyond demonstration flights and test programmes to the use of advanced biofuels for United’s ongoing operations,” it said.
United is to purchase up to 15 million gallons of sustainable biofuel from AltAir Paramount over a three-year period.
Speaking in March, United Airlines spokesman Charles Hobart commented: “The mix is 30% biofuel with 70% traditional fuel until 25 April on our B737 flights between Los Angeles and San Francisco, but then we’ll be bringing in AltAir fuel across all our operations at LAX – dropping it into our existing stockpile of traditional fuel.”
He noted that the US Federal Aviation Administration does not allow more than 50% biofuel in the mix. “Granted, that’s a small percentage of all ongoing flights; however, the total amount over the three years covered by this agreement (15 million gallons) equates to 12,500 flights between LAX and SFR using traditional fuel.
“It’s hard to say yet whether it will be cost-effective. Traditional petroleum-based fuel is a volatile market and right now it’s down, but we wouldn’t want to abandon the initiative. Investing in biofuel is a way to hedge against the volatility of petroleum. Molecularly, it’s identical to traditional jet fuel [ASTM D1655] – that’s part of the process that AltAir undertakes.”
United has collaborated with AltAir since 2009 with the aim of bringing an ongoing source of sustainable aviation biofuels to an airport. A United statement explained that AltAir had retrofitted portions of the Paramount Petroleum Corporation – a subsidiary of Alon USA Energy – refinery in Paramount, California, to create a 35 million gallon per year advanced renewable fuel unit that converts sustainably sourced non-edible, natural oils and agricultural wastes into jet fuel. It is expected to provide a reduction of over 60% in lifecycle carbon emissions when compared to fuel produced from traditional petroleum.
Hobart is keen to highlight United’s US$30 million investment in US-based alternative fuels developer Fulcrum BioEnergy, Inc – “a pioneer in converting MSW (municipal solid waste – basically, household garbage) into jet fuel. We expect this to be cost-effective. Fulcrum is going to be building refineries at locations strategic to United’s operations between 2018 and 2021. They expect to produce around 90 million gallons per year at full capacity. In 2018, production is anticipated to be around 13 million gallons.”
With regard to hybrid technology along the lines of easyJet’s current development programme, United has no plans at the moment. Instead it is focusing on improving the efficiency of its aircraft and ground vehicles. The carrier will soon take delivery of new, more efficient aircraft including B737-MAX9s, B737-900s, B787s and A350s, as well as Embraer E-175s that will be used on the regional routes operated by its partners. “Also 70% of our ground equipment is electric,” Hobart notes, adding: “The best way to limit our footprint on the environment is to use efficientequipment and alternative fuels.”
Other airlines placing their faith in alternative fuels include Air New Zealand and Virgin Australia, which in March announced they would work together to find local sources of aviation biofuel, and issued a request for information that is open until 30 May.
Air New Zealand chief flight operations and safety officer Captain David Morgan believes this is a key initiative under the airline’s carbon management programme, continuing: “By working in partnership with our alliance partner Virgin Australia we hope we can stimulate the local market, drive innovation and investment and potentially uncover a sustainable biofuel supply suitable for our respective operations.”
Virgin Australia head of sustainability Robert Wood adds: “Aviation biofuel offers a significant opportunity for the aviation industry to reduce emissions whilst also building long-term fuel security for the sector.”
One of the potential sources of biofuel is so-called ‘super plants’. Boeing, Etihad Airways, Masdar Institute of Science and Technology and Takreer (a jet fuel company based in the UAE) have launched a new facility in Masdar City, near Abu Dhabi International Airport, for the cultivation of plants that will produce renewable aviation fuel.
In an article published by Boeing in March, Dr Alejandro Rios, director of the Sustainable Bioenergy Research Consortium (SBRC) at Masdar Institute, said: “Seawater and sand, which most people consider a weakness when investigating bio-energy, turn out to be our strengths,” as they provide an ideal environment for the salicornia plant, a salt-tolerant halophyte that can grow in seawater. Its seeds contain plant oils that can be turned into jet fuel, while its sugars and proteins may also be used for biofuel (among other products). Research at the SBRC has also shown that these plants can produce biofuel more efficiently than other well-known feedstocks.
The Seawater Energy and Agriculture System (SEAS) is also home to an aquaculture farm for shrimp and fish, whose waste nourishes the plants – which in turn clean the water and air as they grow, Boeing said.
Marc Allen, president of Boeing International, added that the SEAS facility “shows real promise to transform coastal deserts into productive farmland supporting food security and cleaner skies”.
Back at ICAO, the spokesperson points out that sustainable alternative fuels are one of the elements of the ‘Basket of Measures’ agreed by the organisation’s member states to meet its carbon neutral goal from 2020. While ICAO does not conduct primary research on alternative fuels, it does maintain the Global Framework for Aviation Alternative Fuels, which provides up-to-date information on alternative aviation fuel projects worldwide. Investment in such projects comes from a broad range of stakeholders, including the public sector, fuel producers, feedstock producers, airports, airlines and aircraft manufacturers.
The spokesperson observes: “Our work helps to inform policy decisions that are taken by our member states. Technical areas that are currently being evaluated include future projections of alternative jet fuel availability and their potential effect on lifecycle emissions, as well as the development of a lifecycle assessment methodology for use in a global market-based measure.”
Furthermore: “ICAO is aware of research into the use of hydrogen fuel cells for aircraft, in particular as a source of energy for the auxiliary power unit (APU). This technology has the potential in the future to reduce aircraft emissions. Drop-in sustainable alternative fuels are a technology that is available today that delivers reduced lifecycle CO2 emissions and lower particulate matter emissions. They can be used by any aircraft without modification. In the future, these technologies may very well complement each other.”
Large-scale adoption
ICAO’s spokesperson believes: “With more than 2,000 commercial flights operated with a blend of alternative fuels and kerosene and three production paths certified so far, [the presence of] alternative fuels in aviation is a reality.”
They are essential to ICAO’s environmental strategy to achieve carbon neutrality from 2020. They also form an integral part of airlines’ environmental strategy. Indeed, sustainable alternative drop-in fuels are the only renewable energy option available for aircraft today, he notes.
“So, while the technical feasibility, the environmental impacts and the safe use of biofuels have been demonstrated, integrated thinking is now required to accompany their large-scale deployment. It means that a supply chain approach must be taken to overcome the cost and other barriers to biofuel production at commercial scale. Local supply chains should be considered, bringing biofuel production closer to the airports, supporting the social and economic development of the regions where the production is located,” the spokesperson urges.
He emphasises that a holistic approach should aim to increase public awareness, as public support is necessary to “make the biofuel revolution happen”.
ICAO has identified scenarios in which the industry could fly on 100% sustainable alternative fuels in the future; this would, of course, depend on the policies put in place for the development and deployment of such fuels. “Switching from conventional fuels to low-carbon alternatives is the next challenge faced by all businesses and biofuels are the game-changer of the aviation sector,” the spokesperson concludes.
ICAO intends to have its second Conference on Alternative Fuels in 2017.
The global picture
The ICAO Global Framework for Aviation Alternative Fuels shows that more than 30 states are partnering with research institutes and the industry to develop sustainable alternative fuels for aviation.
For instance:
SkyNRG is a partner of the ‘Fly Green Fund’, which is aimed at establishing an entire supply chain for biofuels in the Nordic countries
In Norway, since January 2016 all airlines refuelling at Oslo Airport can have sustainable jet fuel delivered from the airport’s main fuel farm, via the existing hydrant system. Oslo then became the world’s first biofuel hub
Brazil-based airline GOL’s biofuel programme is based on the ‘farm to fly’ concept, where raw material from family farming is prioritised and co-benefits are encouraged. Thus, it contributes to the reforestation objective of the Brazilian government
Canada, the UK, South Africa, Spain, Germany, Indonesia and the UAE are also amongst those active states that seek to develop biofuels or aviation on a commercial scale
In the Pacific region, meanwhile, Virgin Australia’s Wood observes: “We are seeing the development of the aviation biofuel industry accelerate internationally but that is not yet the case for our region. We are confident that our collaboration with Air New Zealand to procure a large volume of aviation biofuel will de-risk investment in the sector, creating high-tech, high-skilled jobs in the region.”
