When Greta Thunberg, the youngest TIME Person of the Year, traversed the Atlantic on a sailboat, she once again exposed a serious and growing sustainability problem in transportation. Unfortunately, the majority of us can't spend weeks sailing back and forth across the ocean. One of the only things we can do today is purchase carbon offsets and hope that those donations reduce our impact.
However, I don't believe carbon offsets are sustainable long-term. In 2018, the commercial aviation industry reportedly accounted for 918 million tons or about 2.4% of global CO2 emissions from fossil fuel use. While 2.4% may not seem like much, the International Council On Clean Transportation reported that CO2 emissions from commercial aviation increased by 32% between 2013 and 2018. If this trajectory continues, some say aviation could account for over 25% of the worldwide carbon budget by 2050. While bio and synthetic fuels are the other industry-standard responses, efforts I've seen have been small and advancement slow. In addition to these fuels being more expensive by many estimates, their scalability may be limited. Moreover, they may not address particulate and nitrogen oxide (NOX) emissions adequately, less-publicized serious pollution problems in aviation that one study identified.
At the same time, the U.N. warns that human-sourced CO2 emissions must be reduced by 45% of 2010 levels by 2030. Therefore, we have only 10 years to make a significant change or face catastrophic environmental and economic consequences. Considering that aircraft can stay in service for 20 to 30 years, it’s obvious to me that our normal incremental improvements are not going to work. Instead, we should make some immediate and fundamental changes in how we power aviation. If the industry ignores this, it faces the risk of regulatory pressure or severe growth headwinds from cultural and social changes.
The Electric Era
To solve these problems, we should work to create new, truly zero-emission fuels. Building on years of great decarbonization momentum in other industries, such as the increase in U.S. electric vehicle sales, electrification is the logical next frontier to me. The U.S. is gradually reducing emissions from electricity, and according to IEA, the electric vehicle industry is growing gradually in several regions. It’s time for aviation to follow suit.
When history looks back, it might view 2019 as the year we got serious about electrified air travel. Startups tackling the commercial aviation challenge are pursuing a variety of novel propulsion systems. Three of them flew real, commercially relevant zero-emission aircraft in 2019. My company — a hydrogen-electric powertrain company — recently flew a modified Piper airplane. In June 2019, Ampaire had a maiden flight of its electric hybrid Cessna. Finally, Harbour Air and MagniX flew a six-passenger, battery-electric seaplane on a short test flight in December 2019. With several other startups and some of the aviation majors, like Airbus and Scandinavian Airlines, announcing their future electrified aircraft plans, the industry is beginning to move.
Yet serious challenges remain. Aircraft are extremely weight-sensitive, which is a challenge for battery development. And if the multi-decade history of battery development is any indication, we can truly rely only on modest, 3–5% annual improvements like those of the lithium-ion battery. Therefore, realistically, I don't believe that battery-powered aircraft will have any appreciable share of aviation anytime soon — and not by 2030. Extending battery range using fossil fuel generators is likely possible but challenging to scale, and according to NASA research, turbo- and hybrid-electric aircraft are promising but challenging due to weight and complexity issues. They may also create significant emissions for any but the shortest routes.
What the industry needs is a practical approach to deliver longer zero-emission range in the near term, which can reliably scale to 1,000 miles or more in larger aircraft. This leads to the next logical fuel option for zero-emission power: hydrogen.
Hydrogen-Powered Flight Advancements
Hydrogen has been considered as aviation fuel before — from the CL-400 to the Soviet Tu 155 and the hydrogen-electric-powered Boeing in 2008. However, more recent technology and safety improvements, combined with growing real-world experience with ground vehicles such as trains, are finally making a practical hydrogen-electric commercial aircraft possible. Hydrogen-electric safety and operational reliability are now more established in numerous ground mobility applications — from fuel-cell-powered cars to an estimated 20,000 hydrogen fuel-cell forklifts in warehouses across the U.S.
There are already several hydrogen-electric aviation programs underway. My company is working to launch a 500-mile, 19-passenger aircraft by 2023. HES has announced a four-passenger concept that could travel between 500 and 5,000 kilometers (311 to 3,107 miles) and expects to have a prototype in 2025. Another four-seat effort — although more academic — is the Pipistrel, Hydrogenics, University of Ulm and German Aerospace Center airplane called HY4, which has been flying since 2016.
Of course, there are some challenges of hydrogen to overcome. Any new fuel requires new infrastructure. A new supply and delivery chain would have to be built across all airports. But we could do it profitably by effectively paying for it through the savings from fuel and maintenance costs that hydrogen-electric powertrains could bring. Note that battery-electric aircraft would require an infrastructure build-up as well. Access to renewable power near the airports may be limited, so on-site production would be more difficult and affect local economies. The solution could be a new delivery method, such as ammonia, or building hydrogen pipelines.
As 2020 begins, I believe the aviation industry is entering an exciting Electric Age. For the first time since turbines emerged 80 years ago, we are witnessing a fundamentally new propulsion technology take hold. We could see more electrified aircraft take flight and many records break as entrepreneurs and pioneers push the boundaries of what we think is possible. It will be up to manufacturers, operators and regulators to pursue zero-emission aircraft or risk playing a part in humanity's inability to reach its CO2 reduction goals.
As Miss Thunberg would say, "The rules have to change. Everything needs to change. And it has to start today."
