Researchers at Chalmers University of Technology in Sweden have performed the world’s first life cycle assessment (LCA) of an existing, two-seater, all-electric aircraft, with a direct comparison to an equivalent fossil fuel-powered one.
According to the study, after just one quarter of the expected lifespan of the electric aircraft, the climate impact is lower than that of the fossil fuel-based aircraft, provided that green electricity is used.
The downside, however, is increased mineral resource scarcity, researchers noted.
Aviation has grown considerably in recent decades and accounts for approximately 2% of global carbon dioxide emissions and some 4% of all climate change impacts annually, the researchers said, noting electric aircraft are “one option for reducing these environmental impacts.”
The first electric aircraft are already in operation today and are mainly small planes used for pilot training and short flights in the immediate area. This is the type of plane that was studied in the life cycle assessment.
“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. In a larger perspective, the study shows that battery-powered electric aircraft have the potential to significantly reduce environmental impacts of aviation,” says Rickard Arvidsson, the lead author of the study.
Same Aircraft, But Different
The researchers examined a commercially available battery-electric aircraft with two seats, the Pipistrel Alpha Electro. The same aircraft is also available as a fossil fuel-powered model, enabling the researchers to make a direct comparison.
The team investigated the entire impact of each aircraft from “cradle to grave” — from raw material extraction to end of life — with a functional unit of 1 hour flight time. Data and records from the aircraft manufacturer informed much of the study, the researchers reported.
A wide range of impact categories were considered, with a focus on global warming from greenhouse gas emissions (e.g. carbon dioxide), mineral resource scarcity from the use of rare minerals (e.g. lithium for the batteries), particulate matter formation from particle emissions, acidification from acidic emissions (e.g. nitrogen oxides), and ground-level ozone formation from emissions of nitrogen oxides and hydrocarbons.
“The key take-home from this study is that small electric aircraft can have a notably lower climate impact — up to 60% less — and other types of environmental impacts than equivalent fossil-fueled aircraft. However, there is a trade-off regarding mineral resource scarcity — about 50% more even in the most favorable scenario, mainly due to rare metals in the batteries of the electric aircraft,” says Arvidsson.
As with electric cars, electric aircraft are comparatively worse from a climate point of view when the plane is brand new, since the production of the battery consumes a lot of energy and resources. Then, over time, the relative impact decreases as the electric plane is in use and its benefits are realized — namely, emission-free electric propulsion. The longer the electric plane is used, the better it becomes for the environment, and eventually a “break-even” point is reached, according to the researchers.
After approximately 1,000 flight hours, the electric aircraft overtakes the fossil fuel aircraft in terms of less climate impact, after which the electric aircraft is better for the environment, they report. This is measured in carbon dioxide equivalents per flight hour and is true under optimal conditions, where green energy is used.
All use after that becomes a “climate benefit” compared to conventional aircraft.
The estimated lifespan of the aircraft is at least 4,000 hours, or four times as long as the break-even time.
“The lifetime of the lithium-ion batteries, however, would have to be about twice as long for the mineral resource scarcity to be about the same for the electric airplane and the fossil-fuel aircraft. Alternatively, have double the energy storage capacity such that only one of two packs are needed onboard for the same flight time,” says Senior Researcher Anders Nordelöf, one of the other authors of the study.
New and Better Batteries
In the study, the researchers discuss the further development of batteries as a major step towards reduced lifecycle impacts of the electric aircraft.
Already today — but after the study was carried out — Pipistrel has managed to extend the life of the batteries as much as three times, the researchers said.
New battery technologies could further improve both climate impacts and mineral resource scarcity, they added.
“There is a constant development of lithium-ion batteries that can improve the environmental performance of the electric aircraft and make it relatively even more preferable than the fossil-fueled one,” said Arvidsson. “There are also new battery technologies that could be developed and be applicable to electric aircraft in a longer time perspective, such as lithium-sulfur batteries, although these are still in an early phase of technology development.”
The study, “Life cycle assessment of a two-seater all-electric aircraft,” was published in The International Journal of Life Cycle Assessment.
Highly theoretical and completely devoid of any real or practical aspect.
“provided that green electricity is used.”
This says it all. Green energy is a LONG way from prime time. Why don’t they do a real comparison? They know the numbers won’t work out…
One big advantage of electric flight is that it is generally cheaper to power an electric plane than to fuel a fuel-burning plane, because the electric motors are more efficient than the fuel-burning engines.
As battery density and cost increases, thanks in large part to auto EV demand, longer Electric flight starts to be more feasible. Not all battery chemistry is as flammable as Lithium ion, and even NMC batteries are not nearly as combustible as gasoline engines. Stipulating green energy probably simplified the analysis as 0% carbon emissions is easier to analyze than trying to model than the carbon emissions from electricity derived from a mix fossil fuel-burning. Plus green energy from solar panels and wind turbines is now generally cheaper than electricity from fossil fuels due to the lack of fuel costs. Green energy also doesn’t the freshwater supply requirements that boiler-based power plants do. In short, the article points in the direction of the future.
“where green energy is used“
So… the article is relatively meaningless. Where exactly is pure green energy used? Powered by coal.
I told Wilbur and I told Orville…..”pretty cool but they’ll never prove to be useful for anything!”
Breaking news….there’s no free lunch.
Simplified: Your robbing Peter to pay Paul and can only do it for 50 minutes.
If folks think that the buyers of E-aircraft are buying them for the ‘reduced climate impact’, vs the total operating cost and operating economy… what are they smoking.?
The Pipestral Electro-alpha cost $10’s of thousands more than the gas model , for an aircraft that can fly for 50 minutes, at best. Plus, the $15-20K cost of the charger and utility connections.
Unless flight schools are getting huge subsidies, who will buy these.?
Unless there is a 15X improvement in the kWhr per pound of the battery, they may get off the ground, but won’t go far.
This reminds me of the ‘dot-com’ bust of 1999…’vapor’ companies.
We’ll see if any of these aircraft actually become usable over the next 5 – 10 years…!!
“The researchers examined a commercially available battery-electric aircraft with two seats, the Pipistrel Alpha Electro …”
Aircraft designed to be electric from the ground up would presumably be a lot more efficient.
Electric pure battery aircraft are toys compared to other forms of energy. They are also dangerous because batteries are influenced by temperature. The energy to weight ratio is extremely poor. Also in case of spontaneous fire there is no escape. The only electric airplane that will function properly is a hybrid with green hydrogen.