Sustainable Aviation Market Takes Global Stage

By Meredith Roaten
Wisk Aero

Wisk Aero LLC image

FARNBOROUGH, United Kingdom — Outside one of the world’s largest air shows, the temperature was climbing into the hundreds as a July heat wave swept across Europe.

Inside the air-conditioned chalets and less air-conditioned exhibition halls, industry executives and government officials were showing off aviation technology that they hope will reduce carbon emissions and help slow the effects of climate change.

While it was too late to avoid the sweltering heat during the show, aerospace companies are exploring electric and hybrid-electric engines, hydrogen power and sustainable aviation fuel to cut down on the carbon emissions that are worsening the impact of climate change.

Aviation is estimated to be one of the largest contributors to the U.S. military’s carbon footprint. In 2017, the Air Force purchased $4.9 billion worth of fuel — the most of any service in that year — according to 2021 research by Lancaster University academics titled “The Carbon Bootprint of the U.S. Military and Prospects for a Safer Climate.”

The World Economic Forum last year estimated that the airline industry is responsible for nearly 3 percent of global carbon dioxide emissions.

While there is a growing interest by government customers to reduce carbon emissions, discussion tends to be focused on the future, Dale Swartz, an analyst for consulting firm Mc­Kinsey said during a panel discussion at the airshow. The technology just isn’t mature enough yet, he said.

“I think as this gets proven out, I think as the economics continue to be more favorable in a lot of ways, and you have those proof points there, you’re going to see a lot more of it,” he said.

Internationally, governments are looking at ways to become more carbon neutral, said Robin Riedel, an analyst for McKinsey.

He pointed to the Air Force’s technology incubator program, Agility Prime, as an example of the impact the military can have on the sustainable aviation space. AFWERX, the service’s tech incubator, has helped connect companies like Vermont-based start-up Beta Technologies with Defense Department funding.

But it can be challenging to transfer technology from passenger to military aircraft, he noted.

“The performance requirements in the defense environment are often a bit higher than a commercial environment,” he said.

One aerospace prime with a big defense business that is taking a leap toward green aviation is Boeing.

Boeing-backed company Wisk Aero put its all-electric vertical take-off and landing air taxi on static display at the airshow. Though the commercial aerospace company intends to use the plane for passengers, the technology could eventually be used for defense purposes.

“Anything we do in [the commercial] world drops back in the defense world as our customers evolve and are ready for it,” Ted Colbert, CEO and president of Boeing Defense, Space and Security, said during an event leading up to the air show.

The company is leveraging digital engineering to reduce carbon emissions in its defense business, he noted. Colbert pointed to an example of one defense customer, which he declined to name, that saved “a ton of fuel on several missions” because of the data collected through digital engineering tools.

“We use that already today to support efficiency in the defense space for our customers with specific products,” he said.

The eVTOL market at the show was crowded. A full-scale mockup of the air taxi VX4, designed by Vertical Aerospace of the United Kingdom, was on display in an exhibit hall. Aerospace companies Eve and Supernal also displayed cabinet concepts for their electric aircraft designs.

Boeing has also flown five different aircraft using hydrogen propulsion technology, Steve Gillard, Boeing’s U.K. and Ireland sustainability director and international defense sustainability leader, said in an interview. Boeing performed six demonstrations of hydrogen technology, according to the company’s sustainability presentation.

“Boeing isn’t necessarily thought of as being the hydrogen guy,” but the company is exploring its potential, including in space, Gillard said.

However, the majority of the carbon reduction in the future will come from sustainable aviation fuel, which is made from renewable sources, he said.

“It’s not going to be too different in the military world as well, just because of the energy density of some of the applications that we’re looking at,” he said.

Because NATO members are taking climate change seriously, it is encouraging militaries to buy more sustainable aviation fuel, he noted.

“They recognize the important role that the military can play in scaling SAF and getting it to commercial scale. … It’s the only way that the military can meaningfully decarbonize quickly,” he said.

Boeing purchased 2 million gallons of sustainable aviation fuel for 2022 commercial operations, according to the company.

Another company moving into the electric aircraft space is Canadian aircraft training company CAE, which signed an agreement with French aerospace company Safran to acquire an engine for an electrified version of its single engine trainer, the Piper Archer. Called ENGINeUS 100, the aircraft’s engine delivers a maximum of 100 kilowatts at take off and contains a fully integrated motor controller.

Because training aircraft weigh less than others, they represent a big opportunity for electric propulsion, Bruno Bellanger, executive vice president and general manager of the power division at Safran Electrical and Power, said on the sidelines of the air show.

Most of the company’s efforts will be spent demonstrating that the electrified version of the aircraft can fly in every condition, Bellanger noted. Certification is expected by 2023.

The defense industry becoming more green is inevitable, he said. Because of their smaller size, training aircraft could easily kick off the transition.

For example, the U.K. military is already looking into a greener training alternative. The Royal Air Force announced last year that it was seeking input from industry on how to pursue a zero-emissions option for its light trainers.

Currently, the Royal Air Force uses the Grob Tutor T1 to train pilots. However, the service is looking for a new aircraft to enter the fleet by 2027, the Defence and Security Accelerator, the U.K. military’s tech incubator, said in an announcement last year.

While Bellanger said there is a market for all kinds of sustainable aviation, fully electric propulsion will likely remain in the domain of small aircraft with short ranges and small payloads.

There is crossover potential for Safran’s engine technology in hybrid electric systems, he noted. By working on “building block” technology that can be applied in different engines for electric propulsion, the company can be relevant in both electric and hybrid electric markets, he said.

“You can save fuel, and hybridization can also provide some additional benefits to the aircraft, such as noise reduction and … maintenance cost reduction as well,” he said.

While some companies are going in on electric technology, hydrogen fuel may offer another alternative. During the air show, Cranfield Aerospace Solutions showed off its plans to convert a Britten Norman Islander light utility aircraft into a hydrogen-powered passenger aircraft by 2025.

Paul Hutton, CEO of U.K.-based Cranfield Aerospace, said the sustainable aviation field may be too optimistic about the energy density of batteries. In Cranfield’s assessment, the most flight time it could get out of an Islander by 2025 is 20 minutes using electric propulsion.

Hydrogen is three times more energy dense than aviation fuel, so it is possible to get the full-hour range needed for Cranfield’s regional transportation plans. That also means less hydrogen is needed to power an aircraft than traditional fuel.

Vertical take-off and landing vehicles require more power for lift off, which is why Cranfield is converting a more traditional design, he explained.

The Target True Zero initiative — an effort sponsored by the World Economic Forum and the University of Cambridge’s Aviation Impact Accelerator — released a report during the air show that concluded hydrogen could be a solution for mid-range and long-distance flights by 2035.

The report also noted that the energy density and life cycle of batteries are two of several areas that need to be improved to unlock the technology’s true potential.

The report predicted a maximum operating range of about 400 kilometers by 2035 with an additional 200 kilometers in range by 2050.

Hutton called hybrid-electric engines a “dead end” for Cranfield Aerospace’s business case. Because of the additional energy required to power the extra weight of a dual engine, Cranfield only saw a small reduction in carbon emissions which won’t bring customers significant return on investment, he said.

“What’s the point of spending a number of years developing an airplane that gives you at best 10 percent CO2 reduction because the operators will buy an airplane and keep it for 20 years,” he said.

But there are still unresolved issues for the technology. While hydrogen eliminates most carbon emissions from aviation, there could be other environmental impacts from the vapor trails left by hydrogen power, the report warned.

Hydrogen is also expensive, but prices could drop over time as more aerospace companies explore the technology, Hutton added.

Meanwhile, smaller, lighter, uncrewed aircraft represent an opportunity for the military, he added.

Cranfield Aerospace has been approached by other companies whose customers are interested in uncrewed aircraft with heavier lift and longer range but still produce zero emissions, he said.

In a conflict, using hydrogen could have a logistics advantage, he explained. Because hydrogen can be produced with electrolyzers, the military force wouldn’t have to haul fuel to the edge of a contested area.

“If you’re trying to set up a facility at the other end of the world, there might be some tactical advantage of being able to deploy a system electrolyzer and manufacture your own fuel locally,” he said.

At the end of the day, collaboration within industry is what is going to push the needle forward on green technologies, said Sam Healy, group corporate responsibility and sustainability director at U.K. defense company QinetiQ. Companies working together could produce innovation that an individual couldn’t have come up with alone.

“One of the things that strikes so many people is almost how big this is, how overwhelming it is, and it can seem insurmountable,” she said during a panel at the airshow. “What we need to do is recognize that … this is a shared endeavor that we can work together collectively across the sector to solve.”


Topics: Aviation, Climate Change

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