Green hydrogen is emerging as an attractive alternative for the aerospace industry, which is being encouraged to move towards sustainable solutions and contribute to the 1.5 degree target set out in the Paris Agreement. As the world looks to decarbonise transport and energy systems, green hydrogen – an emission-free fuel produced by electrolysis of water from renewable energy – offers great potential for the sector. One of its most innovative applications is its use in stratospheric balloons, which could redefine near-space operations without emissions or aerosols.
What is green hydrogen?
Green hydrogen is created by breaking down water molecules into dioxygen and dihydrogen using electricity generated from renewable sources (solar or wind power, for example). Unlike conventional methods of hydrogen production linked to the petrochemical and gas industries, this process does not emit greenhouse gases, making a major contribution to decarbonisation efforts in all sectors, including aerospace.
Stratospheric balloons: A new frontier
Stratospheric balloons powered by green hydrogen are attracting increasing interest as a sustainable alternative for a variety of aerospace applications. These lighter-than-air (LTA) vehicles use hydrogen for lift, giving them unique advantages:
- Zero emissions: Hydrogen combustion produces only water vapour, which eliminates the pollutants traditionally produced when hydrocarbons are burnt.
- High altitude operations: These balloons can operate at altitudes of 20–50 km, ideal for scientific research, telecommunications, and surveillance.
- Cost efficiency: By generating hydrogen on-site through renewable energy sources, operational costs and logistical challenges are significantly reduced. This can even be integrated directly into the balloon production site to streamline the supply chain.
Latest innovations
In September 2024, Swiss pilots Laurent Sciboz and Nicolas Tièche demonstrated the potential of green hydrogen. Their balloon flight from Gruyère in Switzerland used hydrogen generated entirely by solar energy. This milestone underlines the feasibility of hydrogen production for aeronautical purposes.
In the aerospace sector, Zephalto illustrated the potential of hydrogen during its latest flight at 6 kilometres altitude. The company has developed a reusable hydrogen balloon capable of carrying passengers and payloads into the stratosphere. Made from sustainable materials, the envelope can be reused several times, significantly reducing its carbon footprint. Each flight emits just 26.6 kg of CO2, less than the carbon footprint of manufacturing a pair of jeans.
Progress has also been made in the field of solid-state hydrogen storage and seawater ballasting systems, which have improved the efficiency of these balloons. For example, the salt water ballast can be used as a flow battery to produce hydrogen on site. This innovation reduces dependence on external refuelling and favours long-duration missions.
Applications in aerospace
Stratospheric balloons powered by green hydrogen could revolutionise a number of sectors:
- Scientific research: High-altitude balloons can carry instruments to study atmospheric phenomena or monitor climate change.
- Telecommunications: They can be used as communication relays during natural disasters or in remote areas.
- Military operations: Hydrogen balloons are used for surveillance, reconnaissance and even drone deployment.
- Space exploration: These balloons enable experiments to be carried out in near-space environments. Some industrial players are also looking into the possibility of platforms for launching small satellites.
Scaling up green hydrogen for a zero-emission future
The global green hydrogen market is expected to grow at a compound annual growth rate (CAGR) of over 31% between 2024 and 2032, driven by advances in electrolysis technologies and increased investment in renewable energy infrastructure. For aviation in particular, Airbus aims to introduce hydrogen-powered aircraft by 2040, underlining the industry’s commitment to this clean energy source.
Green hydrogen is transforming the aerospace industry by offering an alternative to fossil fuels, which are often used to power certain space launch vehicles. With advances in electrolysis and the optimisation of cryogenic storage, this technology is becoming a viable solution for emission-free flights, paving the way for a more sustainable industry.
With many governments and companies prioritising decarbonisation, the era of hydrogen-powered green aerospace is closer than ever. As technology advances and costs fall, solutions such as Zephalto are redefining the way humanity explores the earth’s atmosphere and space, cleanly and responsibly.