Hydrogen-powered aviation reaches milestone with ZeroAvia’s flight

The largest aircraft powered partly by hydrogen took flight this week over the English countryside.

The startup ZeroAvia said it successfully flew its 19-seat prototype plane during a 10-minute flight test on Thursday, marking an early but important step toward hydrogen-fueled flying. The twin-engine aircraft was retrofitted to include fuel cells — which convert hydrogen into electricity — and batteries on one side, with the other side using an oil-burning jet engine.

ZeroAvia’s flight from Cotswold Airport comes as the global aviation industry is searching for viable alternatives to highly polluting fossil jet fuel.

Around the world, commercial air travel accounts for over 2 percent of energy-related carbon dioxide emissions, a percentage that’s set to soar in the coming years as passenger travel takes off. And as international air travel approaches pre-pandemic levels, the aviation sector is already driving an overall uptick in emissions from the burning of fossil fuels, which hit a record high last year.

In the near term, major airlines and plane manufacturers are seeking to curb emissions by designing more fuel-efficient engines, electrifying ground operations and increasing their use of ​“sustainable aviation fuel,” a broadly defined term that today mainly refers to fuels made from used cooking oil and animal fats. Companies are also developing battery-powered planes to hop between islands or make regional jaunts.

As a long-term solution, however, the industry is increasingly considering hydrogen. So far, the carbonless fuel has been tested dozens of times in tiny, single-digit-passenger prototype models. ZeroAvia’s most recent flight test represents a significant step up from earlier efforts, said Val Miftakhov, founder and CEO of the Hollister, California–based company.

“The first flight of our 19-seat aircraft shows just how scalable our technology is and highlights the rapid progress of zero-emission propulsion,” he said in a statement. ​“This is a major moment, not just for ZeroAvia, but for the aviation industry as a whole.”

Aviation companies are pursuing two forms of hydrogen aircraft: models with combustion jet engines burning liquid H₂, and models with fuel-cell-battery systems using gaseous hydrogen. With the latter, hydrogen flows into the fuel cell and spurs an electrochemical reaction that produces electricity; that in turn drives electric motors and propellers. Since the fuel cells don’t burn hydrogen the way engines do, they don’t generate harmful nitrogen oxides or fine particulate matter.

However, liquid-burning engines are expected to produce more power than fuel cells — enough to cover most short- and medium-haul flights. Fuel-cell aircraft will likely be limited to short-haul regional routes, which are typically less than 400 miles, according to researchers at the International Council on Clean Transportation.

ZeroAvia’s flight, which was initially planned for July 2022, is part of the HyFlyer II project, a major research and development program backed by the U.K. government. In previous experimental flights, the startup used a six-seat prototype propeller plane equipped with only fuel cells and batteries. In April 2021, a prototype called the Piper Malibu was damaged during a forced landing at another small research airport. The bigger Dornier 228 aircraft tested this week had a different technology arrangement than its predecessors, using both a zero-carbon system and a conventional jet engine.

ZeroAvia said it expects to deliver a 2- to 5-megawatt hydrogen-electric propulsion system that’s certified to fly in 2023, with plans to launch nine- to 19-seater commercial aircraft with a 300-mile range by 2025.