A study by researchers at Chalmers University of Technology, Sweden, has found that electric aircraft can significantly reduce the environmental impacts of aviation – but only if used for long enough.
Aviation accounts for approximately 2% of carbon emissions and 4% of all climate change impacts overall. With little sign of demand slowing, efforts are underway to reduce the environmental impact of flying. Electrification offers the possibility of zero emission aviation, although the technology is mainly limited today to small aircraft used for short flights and pilot training.
“In the short-term future, battery-powered electric aircraft will probably mostly be used for shorter distances, such as what in Norway is called ‘fjord-hopping’, meaning shorter flights between deep fjords,” said Professor Rickard Arvidsson, lead author of the study. “In a larger perspective, the study shows that battery-powered electric aircraft have the potential to significantly reduce the environmental impacts of aviation.”
Arvidsson and his colleagues carried out a life cycle assessment for a commercially available battery-electric two-seater (the Pipistrel Alpha Electro). The aircraft is ideal for direct comparison, with a fossil fuel-powered model also available.
They investigated the impacts of the two aircraft from raw material extraction to end of life, with a functional unit of one hour flight time. Impacts covered many categories, including warming from greenhouse gas emissions; mineral resource scarcity from use of rare minerals (such as lithium); particulate matter formation from emissions; acidification from emissions; and ground-level ozone formation from emissions.
“The key take-home from this study is that small electric aircraft can have a notably lower climate impact – up to 60% less – and a lower level of other types of environmental impact than equivalent fossil-fuelled aircraft. However, there is a trade-off regarding mineral resource scarcity – about 50% more, even in the most favourable scenario – mainly due to rare metals in the batteries of the electric aircraft,” said Ardvisson.
As is the case with electric cars, the electric aircraft is relatively worse for the environment when brand new – this is due to the consumption of energy and resources required to produce its battery. Its relative impact decreases as it enters use, with a break-even point being reached at approximately 1,000 flight hours. After this point, the electric aircraft is better for the environment overall.
The estimated lifespan of this model of electric aircraft is at least 4,000 flight hours.
Further development of batteries is an important step towards reducing the life cycle impacts of electric aircraft, the study said. Since the study was completed, the manufacturer of the Pipistrel Alpha Electro managed to extend the life of its batteries threefold.
“There is a constant development of lithium-ion batteries that can improve the environmental performance of the electric aircraft and make it even more preferable than the fossil-fuelled one,” said Ardvisson. “There are also new battery technologies that could be developed and applicable to electric aircraft in a longer time perspective, such as lithium-sulphur batteries, although these are still in an early phase of technology development.
Source: E&T
