Achieving net zero by 2050 will mean decarbonising aviation, which is responsible for around 2 percent of global energy-related CO2 emissions. This will involve converting aircraft engines to an energy supply based on batteries or synthetic fuels.
In 2015 and 2016, the project Solar Impulse saw Swiss pilots Bertrand Piccard and André Borschberg successfully make the first round-the-world flight in a solar-powered electric aircraft. This was primarily about demonstrating the possibilities of renewable energies and efficient technologies. However, Solar Impulse’s intercontinental and night flights also provided a glimpse of the potential of powerful battery storage and electric propulsion systems for future aircraft. This gave rise to the spin-off H55, which aims to further develop and certify battery-powered propulsion technology for commercial aircraft. The name of the company, headed by André Borschberg, comes from where the firm was first based: in Hangar 55 in Visp.
Achieving net zero in aviation by 2050 is a huge challenge. Firstly, weight plays a major role, and batteries are still much heavier than conventional fuel tanks with the same energy content. A heavier propulsion system reduces payload, and with it cost efficiency and range. The second key challenge is obtaining certification from the relevant authorities. When it comes to proving the safety of new aviation technologies, the requirements are very demanding and the processes very strict. As André Borschberg, co-founder and Executive Chairman of H55, points out: “In aircraft development, there are no short cuts.” This means that innovation is slower-paced than with road vehicles, for example.
H55 intends to first develop the new propulsion technology for relatively simple two-seater training aircraft, designed for training sessions that last around one hour. The plan is to then scale up the system for more sophisticated types of aircraft, such as those used to transport goods or passengers on a regional basis. Last year, the European and Swiss aviation safety authorities granted the firm the necessary approvals to develop and manufacture an electric propulsion system. Meanwhile, flight experience is being gathered with prototypes, and by the end of 2024, type approval should be obtained for a small aircraft, confirming that it complies with Swiss regulations.
One thing that sets this Valais-based company apart is its battery technology, which is adapted to the special requirements of aviation. Twenty years of experience have gone into the development of modular battery packs that can be scaled for different types of aircraft and use specific structures and electronic control units to prevent battery cells from overheating or even catching fire. Such complex patented solutions make H55 an exciting partner for major aircraft manufacturers who have yet to develop expertise in electrification. For example, the firm is developing the battery storage system for a 49-seat passenger aircraft with hybrid electric propulsion on behalf of Pratt & Whitney Canada.
Although a small number of light aircraft are already flying on battery power today, electric propulsion systems are unlikely to be used in long-haul aircraft any time soon, due to batteries’ limited storage capacity. “Clean flying with small regional aircraft could be commercially available by 2030,” explains André Borschberg. For large aircraft, the focus will probably be on hydrogen engines – at least in the medium term. The technologies will have to be improved step by step, and it is likely that a mixture of solutions will be developed and used in parallel: hybrid engines with fossil fuels, which are more efficient but still emit greenhouse gases; hybrid engines with hydrogen, as long as this is produced using renewable energies in order to achieve the climate goals; and fully electric propulsion systems. All options involve batteries and electric motors. H55’s propulsion system can therefore be used and adapted anywhere. Borschberg sees the firm’s clear vision as a recipe for success: “To make flight clean and, in the long term, to get away from combustion engines and fossil fuels.” However, he says there is still plenty to be done before that point is reached.