Hydrogen fuel cells, explained
Cross-industry collaboration is set to unlock the technology’s potential for aviation
Hydrogen fuel cells are emerging as a high-potential technology that offers significant energy efficiency and decarbonisation benefits to a range of industries—including automotive and heavy transport. In a strategic partnership with automotive systems supplier ElringKlinger, Airbus is investing to mature fuel cell propulsion systems for the aviation market. In 1838, judge-turned-scientist Sir William Grove came up with a novel idea: to construct a cell consisting of two separate sealed compartments, each of which was fed by either hydrogen or oxygen gas. At the time, he called his invention a “gas voltaic battery.” Unfortunately, it did not produce enough electricity to be of much use. It remained a scientific curiosity until the 20th century, when English engineer Francis Thomas Bacon matured the original idea to develop the world’s very first hydrogen-oxygen fuel cell in 1932. Bacon’s fuel cell was such a success that it has been used by the space industry to power satellites and rockets for space exploration programmes, including Apollo 11, since the 1960s. As the story goes, then-US President Richard Nixon famously said: "Without you Tom, we wouldn't have gotten to the moon.” Today, hydrogen fuel cell technology is being used for a variety of applications, including to:- provide emergency backup power to critical facilities like hospitals
- replace grid electricity for critical-load facilities like data centres
- power a variety of transportation modes such as cars, buses, trains and forklifts.
Hydrogen fuel cells: how do they work?
Similar to batteries, a fuel cell is a device that converts energy stored in molecules into electricity through an electrochemical reaction. Composed of two electrodes (an anode and a cathode) separated by an electrolyte membrane, a typical hydrogen fuel cell works in the following way: Hydrogen enters the fuel cell via the anode. Here, hydrogen atoms react with a catalyst and split into electrons and protons. Oxygen from the ambient air enters on the other side through the cathode. The positively charged protons pass through the porous electrolyte membrane to the cathode. The negatively charged electrons flow out of the cell and generate an electric current, which can be used, for example, to power an electric or hybrid-electric propulsion system. In the cathode, the protons and oxygen then combine to produce water. Today, Airbus has significant know-how in electric propulsion and fuel cells thanks to work carried out at our E-Aircraft System House and currently taking place at the ZAL in Hamburg. This partnership will be a phenomenal acceleration in bringing hydrogen fuel cells to future aircraft. Because fuel cells generate electricity through an electrochemical reaction, they are a clean source of power. In fact, fuel cells that use pure hydrogen are carbon-free. Some other key advantages of fuel cells include the following:- Unlike batteries that need to be recharged, fuel cells can continue to generate electricity as long as a fuel source (hydrogen) is provided.
- Individual fuel cells can be “stacked” to form larger systems capable of producing more power, thereby allowing scalability. A single fuel cell can produce enough voltage to power small applications, while fuel cell stacks can be combined to create large-scale, multi-megawatt installations.
- Because there are no moving parts, fuel cells are silent and highly reliable.