ZeroAvia Hydrogen Plane: Technical Challenges Emerge

ZeroAvia's Hydrogen Flight: A Closer Look

Last September, ZeroAvia’s six-seater aircraft successfully completed an eight-minute flight originating from Cranfield Airfield in the U.K. The company heralded this event as a “major breakthrough,” marking the first hydrogen fuel cell-powered flight of an aircraft of commercial dimensions.

According to ZeroAvia, the adapted Piper Malibu propeller plane now represents the world’s largest hydrogen-powered aircraft. CEO Val Miftakhov stated that this aircraft size indicates the potential for passengers to soon experience genuinely zero-emission flights.

Examining the Hydrogen Power Claim

However, the extent to which the aircraft was powered by hydrogen requires further scrutiny, and the timeline for passenger flights remains uncertain.

Miftakhov clarified during a subsequent press conference that the energy source wasn’t exclusively hydrogen. He explained that a combination of battery power and hydrogen fuel cells was utilized, though the system allowed for operation solely on hydrogen.

The Role of Batteries and Aircraft Modifications

Further investigation by TechCrunch reveals that batteries supplied the majority of the power during this significant flight. Batteries will also remain a crucial component in ZeroAvia’s extended flights and future aircraft designs.

While the Malibu is classified as a passenger aircraft, ZeroAvia had to remove four of its five passenger seats to accommodate the necessary hydrogen tanks and associated equipment.

Rapid Growth and Future Prospects

Within a short timeframe of under four years, ZeroAvia has progressed from ground-based component testing to securing backing from the U.K. government. The company has also garnered investment from prominent figures such as Jeff Bezos, Bill Gates, and, recently, British Airways.

The central question now is whether ZeroAvia can sustain its progress and ultimately revolutionize the aviation industry.

Here's a breakdown of key aspects:

• Hydrogen Fuel Cells: ZeroAvia is pioneering the use of hydrogen fuel cells in commercial aircraft.
• Battery Integration: Batteries currently play a significant role in powering the aircraft, supplementing hydrogen fuel cells.
• Investment & Support: The company has attracted substantial investment and government support.
• Aircraft Modification: Significant modifications were required to the Piper Malibu to accommodate hydrogen technology.

The Challenge of Sustainable Flight

Currently, aviation contributes 2.5% to global carbon emissions. Projections indicate this figure could rise significantly, potentially consuming a quarter of the planet’s carbon budget by the year 2050.

Alternative solutions like biofuels present challenges, potentially displacing land used for forestry or food production. Batteries, while viable, are currently too heavy for long-distance flights.

Hydrogen emerges as a promising alternative. It can be produced utilizing renewable energy sources like solar and wind power, and boasts a high energy density.

How Hydrogen Fuel Cells Work

Fuel cells operate by combining hydrogen with oxygen from the atmosphere. This process generates electricity, heat, and water as byproducts, offering a clean energy solution.

However, integrating fuel cells into existing aircraft isn't straightforward. Their weight and complexity, coupled with the need for substantial hydrogen storage, present significant hurdles for developers.

The Founding of ZeroAvia

Valery Miftakhov, originally from Russia, immigrated to the United States in 1997 to pursue a doctorate in physics.

Following a period at Google and the establishment of several ventures, he founded eMotorWerks (EMW) in 2012. The initial focus was on creating electric conversion kits specifically for the BMW 3-series.

Early Challenges at eMotorWerks

In 2013, BMW alleged trademark infringement by EMW. Miftakhov agreed to modify the company’s logo and marketing materials to avoid any implication of affiliation with the car manufacturer.

Furthermore, demand for the conversion kits from BMW owners proved to be lower than anticipated.

A Pivotal Shift and Acquisition

EMW subsequently transitioned its focus to developing charging solutions and a sophisticated energy management platform. This strategic change proved successful.

In 2017, Italian energy firm Enel acquired EMW for a reported $150 million. Despite this success, Miftakhov encountered further legal issues.

Legal Disputes and Resolution

George Betak, a former EMW vice president, initiated two civil lawsuits against Miftakhov. These suits included allegations of patent omissions, financial withholding, and document falsification related to intellectual property rights.

Some of Betak’s claims were later withdrawn, and the cases were ultimately settled confidentially in the summer of 2020.

The Birth of ZeroAvia

Just weeks after the sale of EMW in 2017, Miftakhov established ZeroAvia in San Carlos, California. The company’s stated mission was to achieve “zero emissions aviation.”

He anticipated greater interest in aircraft electrification within the aviation industry compared to the response from BMW vehicle owners.

Early Stages: Powering Flight with Batteries

ZeroAvia’s initial public demonstration occurred in October 2018 at Hollister Airport, situated 50 miles southwest of San Jose. Valery Miftakhov integrated a propeller, an electric motor, and a battery system into the bed of a 1969 El Camino, achieving a speed of 75 knots—approximately 85 mph—using solely electric power.

The company subsequently acquired a Piper PA-46 Matrix in December, a six-seat propeller aircraft closely resembling the model that would be utilized in future U.K. trials. Miftakhov’s team then installed the electric motor alongside roughly 75kWh of lithium-ion batteries, a capacity comparable to that found in a base-level Tesla Model Y.

By February 2019, and following FAA approval with an experimental airworthiness certificate granted just two days prior, the fully electric Piper successfully completed its maiden flight. Further testing in mid-April confirmed the Matrix’s ability to reach both its maximum speed and power output, paving the way for a transition to hydrogen fuel.

Import documentation reveals that ZeroAvia received a carbon fiber hydrogen tank from Germany in March. A single company photograph depicts the Matrix equipped with a tank mounted on its left wing; however, no video footage of the aircraft flying with this configuration was ever publicly released, indicating unforeseen challenges.

A setback occurred in July when ZeroAvia’s Research and Development director posted a request on an online forum dedicated to Piper aircraft owners.

The message inquired about the availability of a Piper Matrix for parts, stating that their aircraft had sustained significant wing damage requiring replacement. Miftakhov later verified that this damage occurred during a reconfiguration process of the aircraft, and the plane has remained grounded since that time.

This incident signaled the nearing conclusion of ZeroAvia’s period as a Silicon Valley-based startup.

Transitioning Operations to the United Kingdom

Following a pause in U.S.-based flight testing, Val Miftakhov shifted ZeroAvia’s focus towards the United Kingdom. This move coincided with Prime Minister Boris Johnson’s commitment to fostering ”a new green industrial revolution.”

In September 2019, the Aerospace Technology Institute (ATI), a company receiving support from the U.K. government, provided funding of £2.68 million ($3.3 million) for a ZeroAvia-led initiative known as HyFlyer. Miftakhov pledged to develop a hydrogen fuel cell-powered Piper aircraft capable of flying distances exceeding 280 miles within one year.

The funding was shared between Intelligent Energy, a manufacturer of fuel cells, and the European Marine Energy Centre (EMEC), which was tasked with supplying the necessary hydrogen fueling technology.

Richard Ainsworth, EMEC’s hydrogen manager at the time, explained that ZeroAvia had already demonstrated the feasibility of integrating an electric powertrain into an aircraft. The HyFlyer project aimed to power this powertrain using hydrogen instead of batteries.

Gary Elliott, CEO of ATI, conveyed to TechCrunch that it was “really important” for ATI that ZeroAvia was utilizing fuel cells, rather than relying on a battery system. He stated the need to diversify investment to maximize the potential for success.

ZeroAvia established a base of operations in Cranfield and, in February 2020, acquired a six-seater Piper Malibu, comparable to the damaged Matrix aircraft. Despite successfully fitting and testing the Malibu with batteries by June, further reassurance was required by the government.

An official communicated, in an email obtained by TechCrunch through a freedom of information request, a willingness to discuss addressing any remaining concerns held by the ATI.

Chris Dudfield, CTO of Intelligent Energy, informed TechCrunch that the HyFlyer program progressed without significant issues. However, he indicated that his company remained several years away from enabling flight with a larger fuel cell system and admitted to never having observed ZeroAvia’s aircraft directly.

While the partnership with Intelligent Energy aided ZeroAvia in securing U.K. government funding, it did not provide the power source for the Malibu. Consequently, ZeroAvia needed to identify a fuel cell supplier quickly.

Fuel Cell Propulsion: A Closer Look

ZeroAvia communicated with government representatives in August, announcing preparations for their inaugural hydrogen-powered flight and extending an invitation to the Secretary of State to witness the event.

According to Miftakhov, the demonstration flight utilized a 250 kilowatt hydrogen fuel cell powertrain – representing the highest power output achieved to date in an aircraft. This power level is equivalent to that of conventional internal combustion engines found in Piper aircraft, providing a substantial safety buffer during critical phases like take-off.

Fuel Cell Power Source Details

ZeroAvia has not publicly disclosed the supplier of their fuel cells, nor have they specified the exact contribution of the fuel cell to the total 250kW output.

Following the demonstration flight, PowerCell, a Swedish firm, released a statement indicating that their MS-100 fuel cell was a key component of the powertrain.

However, the MS-100 has a maximum power output of only 100kW, leaving a 150kW deficit. Consequently, a significant portion of the power required for take-off likely originated from the Piper’s onboard batteries.

Battery Assistance and its Implications

Miftakhov confirmed in a TechCrunch interview that the Piper was unable to achieve take-off solely on fuel cell power during the September flight. He indicated that the aircraft’s batteries were likely active throughout the demonstration, offering an “additional safety margin.”

The integration of batteries is common in fuel cell vehicles, serving to regulate power fluctuations or provide temporary power boosts. However, transparency regarding power sources varies among manufacturers.

A key drawback of relying on batteries for take-off is the necessity of carrying their weight for the duration of the flight.

Weight Considerations and Future Goals

“Weight is a primary obstacle for hydrogen fuel cell aircraft,” explained Paul Eremenko, CEO of Universal Hydrogen, which is developing a 2000kW fuel cell powertrain. “We mitigate this by employing a smaller battery, reserved for instances of rapid throttle application.”

Sergey Kiselev, ZeroAvia’s vice president, stated in February that the company aims to eliminate battery usage entirely. He conveyed to the Royal Aeronautical Society that while batteries might offer a temporary “oomph” during take-off, incorporating diverse propulsion or energy storage systems would complicate the certification process.

While utilizing batteries enabled ZeroAvia to conduct a successful demonstration flight for investors and the U.K. government, it may ultimately impede the commencement of commercial passenger flights.

Addressing the Challenge of Heat Dissipation

Fuel cells, lacking a conventional exhaust system for waste heat removal, typically require sophisticated air or liquid cooling mechanisms to prevent operational overheating.

According to Eremenko, this innovative approach to thermal management represents a core element of their intellectual property, distinguishing their system from a simple assembly of off-the-shelf components.

Since 2012, the German Aerospace Center (DLR) in Cologne has been actively involved in flight testing hydrogen fuel cell-powered aircraft. Their latest model, the HY4, a purpose-built aircraft, is capable of transporting four passengers over a distance of up to 450 miles.

The HY4 utilizes a 65kW fuel cell integrated with a liquid cooling system. This system incorporates a sizable, aerodynamically optimized duct to facilitate efficient airflow for cooling purposes.

Image Credits: Credit: DLR

Generally, a comparable 100kW system would necessitate a cooling air intake that is both longer and approximately one-third larger in area than that found on the HY4.

Notably, ZeroAvia’s Piper Malibu aircraft appears to operate without any supplementary cooling intakes.

An aviation fuel cell engineer, requesting anonymity due to professional relationships with companies like ZeroAvia, expressed skepticism, stating, “The existing openings seem insufficient for the airflow demands at both takeoff and cruising speeds.”

Miftakhov responded by asserting that they successfully optimized the positioning and configuration of the heat exchangers. He emphasized that no alterations to the aircraft’s overall design were required to accommodate thermal management.

He further stated that the fuel cell operated within a power range of 85 to 100kW during the test flight.

Subsequent to an interview conducted by TechCrunch with ZeroAvia, the company released video footage. This footage depicts the Piper’s fuel cell achieving up to 70kW output during a ground-based test.

This performance could translate to even greater power levels during actual flight conditions.

While sustained long-distance flight validation remains necessary, ZeroAvia’s advancements suggest a potential resolution to the long-standing heat management challenges that have confronted other engineers in the field.

A Larger Vision for Future Aircraft

Aviation Minister Robert Courts witnessed a demonstration flight at Cranfield in September, marking a significant moment. He stated that the event represented a monumental achievement for ZeroAvia and a historic milestone in aviation. Time magazine previously recognized ZeroAvia’s technology as a top invention of 2020.

Expanding Hydrogen-Electric Powertrains

Despite the ongoing HyFlyer extended flight plans, the U.K. government announced HyFlyer 2 in December. This £12.3 million ($16.3 million) project aims to develop a 600kW hydrogen-electric powertrain suitable for larger aircraft. ZeroAvia initially committed to having a 19-seat aircraft ready for commercial use in 2023, a timeline now adjusted to 2024.

Significant Investment in Sustainable Aviation

Concurrent with the HyFlyer 2 announcement, ZeroAvia revealed a $21.3 million Series A investment group. This included prominent funds such as Bill Gates’ Breakthrough Ventures Fund, Jeff Bezos’ Amazon Climate Pledge Fund, Ecosystem Integrity Fund, Horizon Ventures, Shell Ventures, and Summa Equity. A further $23.4 million was raised in late March, this time with British Airways joining the investor pool, though without Amazon’s participation.

Progress and Adjustments to Flight Testing

According to Miftakhov, the Malibu aircraft has undergone approximately a dozen test flights. The long-distance U.K. flight has been postponed to later this year, primarily due to delays caused by the COVID-19 pandemic. Regarding HyFlyer 2, Miftakhov clarified that the initial phase will utilize a combination of batteries and fuel cells. However, the final, certified configuration will derive its full 600kW power from fuel cells.

Challenges and Future Goals

Delivering on its ambitious promises presents a considerable challenge for ZeroAvia. The company aims to introduce a 19-seat aircraft, followed by a 50-seat model in 2026, and ultimately a 100-seat aircraft by 2030.

Lessons from Past Missteps

Hydrogen fuel cells have faced skepticism, stemming from the case of Nikola, a company whose exaggerated demonstration of a hydrogen fuel cell truck led to a stock price collapse and SEC investigation. For innovative startups like ZeroAvia, transparency regarding their current technological capabilities and the obstacles ahead is crucial. This approach, while potentially moderating investor and public expectations, is vital for fostering trust in the development of sustainable air travel.

Collaboration for Hydrogen Aviation

Paul Eremenko expressed strong support for ZeroAvia’s success. He believes their business models are complementary and that combined efforts will facilitate the realization of hydrogen aviation, completing the necessary value chain.