From Small Drones to Commercial Aircraft: The Advancements in Hydrogen Fuel Cell Technology for Electric Flight

Hydrogen fuel cells represent a transformative step in sustainable energy solutions, generating electricity through an electrochemical reaction between hydrogen and oxygen, with water as the sole byproduct. This process eliminates harmful emissions, offering a cleaner alternative to internal combustion engines that release greenhouse gases and pollutants. Furthermore, hydrogen fuel cells are highly efficient, achieving up to 80% efficiency when producing both heat and electricity. Their ability to integrate seamlessly with renewable energy systems like solar panels and batteries enhances their versatility, supporting the development of a more resilient and environmentally friendly energy infrastructure. This adaptability underscores their potential to contribute significantly to global efforts aimed at reducing carbon emissions and transitioning to cleaner energy systems.

In aviation, hydrogen fuel cells hold particular promise, addressing critical challenges in reducing emissions and enhancing efficiency. Unlike traditional jet engines, hydrogen-powered aircraft produce zero greenhouse gas emissions, releasing only water vapor, which significantly minimizes their environmental impact. Moreover, hydrogen offers a high energy-to-weight ratio, outperforming batteries and enabling longer flights. In addition to being environmentally friendly, fuel-cell-powered propulsion systems operate more quietly than conventional engines, reducing noise pollution and creating a more pleasant experience for both passengers and communities near airports.

While the adoption of hydrogen fuel cells in aviation has been hindered by technological and economic challenges, significant progress is being made. Innovations in fuel cell design, advancements in hydrogen storage technologies, and better integration with aircraft systems are addressing these barriers. As these breakthroughs continue to evolve, hydrogen fuel cells are emerging as a cornerstone of aviation’s transition to sustainable and carbon-neutral flight, paving the way for a new era in cleaner, more efficient air travel.

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While hydrogen fuel cells offer immense potential for sustainable aviation, several challenges must be addressed to ensure their widespread adoption. One of the most significant hurdles is hydrogen storage. Storing hydrogen onboard aircraft demands lightweight, cryogenic tanks capable of withstanding high pressures, a requirement that presents complex engineering and cost challenges. These tanks must also meet rigorous safety and performance standards while minimizing their impact on aircraft weight and efficiency.

Dan Steingart, an associate professor of chemical metallurgy at Columbia University, explained that “in a single hydrogen molecule, there is somewhere between one-fourth and one-eighth the total energy available in a single typical jet fuel molecule.” So, for the same amount of fuel, “planes would go one-fourth the distance.” Obviously, that’s not ideal. So large aircraft meant to go any substantial distance would need much larger fuel tanks. And those tanks would need to be frozen to minus 420 degrees Fahrenheit — close to absolute zero — to liquefy the hydrogen. That is almost as cold as anything in the universe can get.

Another key challenge lies in the infrastructure needed to support hydrogen-powered aviation. Developing a global network of hydrogen refueling stations at airports is essential for operational scalability. This infrastructure must be capable of efficiently handling the production, transportation, and storage of hydrogen, ensuring a reliable supply chain for airlines. Hydrogen production, storage, and distribution systems are gradually being established, initially driven by demand from the automotive and heavy trucking sectors. These developments are expected to pave the way for aviation applications.

Economic viability is another critical factor. The cost of hydrogen production—particularly green hydrogen—and fuel cell systems must decrease to compete with conventional jet fuel. Scaling production, improving fuel cell manufacturing technologies, and optimizing supply chains are vital steps toward reducing costs and enhancing affordability.

Regulations: Updating aviation standards to accommodate hydrogen-powered technologies is necessary for widespread adoption.

Addressing these challenges requires collaboration across sectors. Governments, industry leaders, and research institutions must work together to drive innovation and policy development. Investments in green hydrogen production technologies, such as electrolysis powered by renewable energy, and advancements in fuel cell design will play pivotal roles. By fostering partnerships and directing resources toward overcoming these obstacles, the aviation industry can accelerate its transition to a hydrogen-powered future, paving the way for cleaner, more sustainable air travel.

Research and Collaborative Innovations

Despite these hurdles, the aviation industry remains optimistic. Collaborative efforts between governments, research institutions, and manufacturers are accelerating progress. Experts predict that the cost of hydrogen will become competitive with jet fuel by the 2030s, further catalyzing its adoption.

Doosan Mobility Innovation displayed a hydrogen fuel cell power pack for UAVs that can keep the aircraft airborne for two hours on a single charge of hydrogen, utilizing a detachable hydrogen container for easy refueling. Meanwhile, Intelligent Energy unveiled its 800W Fuel Cell Power Module (FCPM), which offers a 10% increase in power density over its predecessor. With this technology, multicopter UAVs can carry a kilogram of cargo for two hours or two kilograms for one hour. The company also plans to offer customizable configurations to meet different operational needs. Additionally, FCHEA member Alakai Technologies is working on a hydrogen fuel cell-powered, all-electric, vertical takeoff and landing (eVTOL) aircraft capable of carrying four passengers, which could further push the boundaries of hydrogen fuel cell applications in aviation.

Advancements by Industry Leaders

The development of hydrogen fuel cell technology in UAVs is not limited to small drones. Boeing’s subsidiary, Insitu, has made significant strides in advancing fuel cell technology for its UAVs. In December 2020, Insitu completed the first flight of the ScanEagle3 UAV powered by a hydrogen-fueled, PEM (proton exchange membrane) fuel cell. The company is now preparing for test flights using a 3D-printed Liquid Hydrogen (LH2) storage tank, which is expected to provide over 10 hours of endurance. The success of these tests has implications not only for UAVs but also for military applications, where fuel cells’ reduced thermal and acoustic signatures offer advantages for covert operations.

On a larger scale, ZeroAvia, a leader in hydrogen-electric aircraft propulsion, has made remarkable progress with its high-temperature proton exchange membrane (HTPEM) fuel cell technology. The company recently tested a 20-kilowatt HTPEM fuel cell stack, achieving a specific power level of 2.5 kW/kg, with the goal of exceeding 3 kW/kg in the next two years. This breakthrough could potentially enable hydrogen-electric propulsion systems for larger commercial aircraft, such as the Boeing 737 and Airbus A320 families. ZeroAvia’s recent successful flight test of a 19-seat Dornier 228 airliner retrofitted with hydrogen propulsion systems further underscores the viability of hydrogen fuel cells for regional airliners. Moreover, the company’s acquisition of HyPoint and its integration of turbo-air-cooled HTPEM fuel cells aim to expand the application of hydrogen propulsion to a broader range of aircraft, including eVTOLs and rotorcraft.

Airbus’ Commitment to Hydrogen-Powered Aircraft

In addition to ZeroAvia, Airbus has made significant strides toward large hydrogen-electric aircraft. Through its ZEROe project, Airbus has integrated a 1.2-megawatt hydrogen fuel cell system with electric motors into an iron pod propulsion system, marking a key milestone toward its goal of developing emission-free aircraft by 2035. The successful testing of this integrated propulsion system is a significant step toward addressing energy and weight requirements for commercial aviation. Airbus’ continued optimization efforts, along with the opening of the ZEROe Development Centre in Lower Saxony, demonstrate its commitment to advancing hydrogen technologies for the aviation industry.

These advancements, driven by industry leaders and innovative companies, highlight the accelerating progress in hydrogen fuel cell technology and its integration into both small UAVs and larger aircraft. With continued breakthroughs in fuel cell design, energy storage, and hydrogen infrastructure, the dream of sustainable, zero-emission aviation is rapidly becoming a reality.

Airbus, a leader in the aerospace industry, is also exploring hydrogen propulsion with its ZEROe aircraft concepts. These designs include hydrogen-powered turboprops and turbofans, targeting entry into service by the 2030s.  Boeing has also conducted tests with hydrogen-powered aircraft, demonstrating the feasibility of hydrogen propulsion for both manned and unmanned flights. The ultimate goal is to integrate hydrogen fuel cells into larger commercial aircraft.

The CHEETA Project

One example is NASA’s CHEETA (Cryogenic High-Efficiency Electrical Technologies for Aircraft) project, which aims to develop an all-electric aircraft platform powered by cryogenic liquid hydrogen. The project is a partnership between NASA and a consortium of eight research institutions, including the Air Force Research Laboratory, Boeing, and General Electric. The initiative will focus on integrating cryogenic hydrogen fuel cells with advanced superconducting technologies to create a highly efficient, lossless electrical system that can drive electric propulsion. By using hydrogen’s chemical energy in conjunction with ultra-efficient electric motors, the project seeks to demonstrate the potential for fully electric aircraft to replace conventional fossil fuel-powered propulsion systems.

This project is particularly ambitious because it also explores the use of superconducting motors, which would allow for highly efficient energy transmission, similar to technologies used in MRI machines. However, integrating these systems into aircraft is a complex task that still requires significant research and development. The ultimate goal is to build fully electric aircraft that can operate with hydrogen as a clean, efficient fuel source. The outcome of this research could pave the way for the commercialization of hydrogen-powered aircraft, contributing significantly to the decarbonization of the aviation sector.

Element One: World’s First Hydrogen-Electric Passenger Aircraft

A promising example of the application of hydrogen fuel cells to commercial aviation is Element One, the world’s first regional hydrogen-electric passenger aircraft. Developed by Singapore’s HES Energy Systems, Element One is designed to carry up to four passengers and offer a range of 500 to 5000 km, depending on whether the hydrogen is stored in gaseous or liquid form. The aircraft is designed as a zero-emissions vehicle, which aligns with global efforts to reduce the carbon footprint of air travel. With its lightweight design and hydrogen fuel cell propulsion, Element One demonstrates a performance level far superior to that of current battery-electric aircraft, which are limited by the low energy density of their batteries.

The aircraft is not just a technological milestone; it is part of a broader vision to create new air routes connecting smaller towns and rural areas. The ability to fly over distances of up to 5000 km opens up the possibility of connecting regions that are currently underserved by conventional aviation infrastructure. This makes Element One a promising candidate for revolutionizing regional air travel, potentially transforming the way people access remote or smaller destinations.

Element One is designed with modular, distributed electric propulsion, which enhances safety through redundancy and ensures that the aircraft can remain operational even if one of the systems fails. HES Energy Systems has spent 12 years developing the necessary technology, and the company plans to build the first flying prototype by 2025. This progress could potentially set the stage for the commercialization of hydrogen-electric aircraft in the near future.

Japan pours billions of yen into plan to build the world’s largest hydrogen fuel cell for aviation

Japan is making significant strides in sustainable aviation with a major investment of ¥17.3 billion (around $110 million) to fund two pioneering hydrogen research projects. One of the key initiatives is the development of a 4MW hydrogen fuel cell propulsion system, the largest of its kind globally. This ambitious project aims to demonstrate the feasibility of hydrogen-powered flight within the next five years, providing a clean and efficient alternative to traditional jet fuel-powered propulsion systems. By converting hydrogen into electricity, the fuel cell system produces only water as a byproduct, making it a promising solution for zero-emission aviation.

The development of a hydrogen fuel cell system of this scale presents several technological challenges, including ensuring sufficient energy density to match jet fuels, managing heat generation, and addressing the complexities of hydrogen storage and delivery. Innovations in fuel cell design, lightweight composite materials for hydrogen tanks, and advanced cooling systems are expected to overcome these hurdles. If successful, the 4MW system could revolutionize aviation, enabling mid-to-large aircraft to operate emission-free and potentially transforming regional and long-haul flights. The project is part of Japan’s broader push for clean energy solutions and is expected to have a significant impact on other sectors, such as maritime and ground transportation, while contributing to global decarbonization goals.