Sustainability in aviation: Is green hydrogen the future?
Sustainability in aviation is a pressing issue for the sector and green hydrogen may be about to revolutionise the energy industry. The fuel is carbon-free and can be made from water, using only renewably produced electricity to split hydrogen molecules from oxygen molecules. It can also be created by reacting natural gas or renewable liquid fuels with high-temperature steam or converting fermented biomass.
With the aviation industry contributing up to 3% of global CO2 emissions, the sector must become more sustainable in order to combat climate change and work towards reaching net-zero in 2050. The UK ETS scheme, which has now replaced the EU ETS scheme for the UK, reaffirms the importance of this for aviation. The scheme aims to encourage emission reductions to help the UK meet its net-zero target. The Paris Agreement and the European Green Deal has also put aviation and sustainability on the agenda as the sector now must find an alternative to kerosene-powered aircraft and green hydrogen may just be the answer.
September 2020 saw the successful flight of hydrogen-powered commercial aircraft over the skies of Bedfordshire, in a world first. ZeroAvia, the company behind the maiden flight, now hopes commercial aviation can be emission free by 2023.
How does it work?
A hydrogen powered aircraft would store liquid hydrogen that would either combust in a hydrogen turbine or made to react in a fuel cell. Either reaction would produce water vapour instead of emitting any CO2.
CO2 would not be produced through the combustion or the production of green hydrogen, instead emitting water. Studies estimate that hydrogen aircraft can help reduce the aviation industry's climate impact by between 50% and 90%.
Other alternatives being considered are electric battery powered flights, however, it is currently not viable for batteries to power long-haul journeys. Hydrogen’s high energy density is three times higher than traditional jet fuel, meaning it can carry more energy per unit of weight.
Another advantage is that it can temporarily store electricity, either through electrolysis or regenerated electricity. These are both key advantages being considered when it comes to addressing alternative fuels for long-haul flights.
There is still a long way to go before fully hydrogen powered aircrafts take to the skies. One challenge in particular is the ways in which the gas is stored aboard the aircraft.
Storing and transporting the highly flammable gas is not easy; it tends to leak easily in the form of a gas, which could be a hazard. Dedicated pipelines are required to transport the gas, which are costly to build and may weigh more, meaning the rest of the plane’s weight may need to be reduced.
Currently kerosene tanks are located in the wings of the plane, however, hydrogen tanks would not be able to reside there due to weight restrictions. This means time and money would also have to go into the restructure and design of existing aircraft.
The rapid growth of renewable energy over the last year has seen investment in wind and solar energy soar. The International Energy Agency (IEA) predicts that this interest will drive down the costs of green hydrogen for the future due to its increased availability. Energy agencies around the world are looking to developments in green hydrogen to boost clean energy supply.
It has been announced that the UK’s first homes equipped with hydrogen boilers and hobs will be completed by April this year and the NHS has outlined its plans to trial hydrogen-powered ambulances in London later this year.
The UK is set to lead an innovative hydrogen propulsion programme costing £54m, called H2GEAR. With an aim is to develop the first hydrogen propulsion system for sub-regional aircraft, industrialising the breakthrough technology to fly aircraft with zero CO2 emissions in the next five years.
Transportation organisations may now look to incorporating green technology, such as hydrogen fuel cells, into their environmental management systems. Q-Pulse Law can help aid your business when it comes to keeping up to date with any legislative or regulatory changes.
Sustainability in aviation is an important part of the collective effort for the UK to become carbon free by 2050. Find out more about green hydrogen and its role in the green industrial revolution plan.