The Challenges Of Electric Air Travel

Climate neutrality targets are designed to guarantee that human activities, such as aviation, stop further contributing to climate change. In order to meet ambitious climate targets, the aviation sector needs to neutralize CO2 emissions and reduce non-CO2 climatic effects. Because we live in a global economy, we crave low emission, fossil fuel-free air travel. How viable is electric air travel? Battery-electric terrestrial transportation is taking hold, so won’t electric air travel be next?

Electrical propulsion can transform aerospace and aviation industries with quieter flights, reduced emissions, safer flight conditions, and reduced costs. It can open up new segments of aviation, including urban air taxis and a new sub-regional market.

The trajectory to zero emissions air travel is an environmental necessity in the face of a worsening climate crisis. Then again, it is particularly hard to decarbonize air travel.

Airplanes emit around 100 times more CO2 per hour than a shared bus or train ride, and the emissions of global aviation are around 1 billion tons of CO2 per year — more than the emissions of most countries, including Germany. Aviation contributes an estimated 2.4{6932ee47e64f4ce8eedbbd5224581f6531cba18a35225771c06e4f1b3f0d9667} of global annual CO2 emissions, most of it from commercial travel.

In recent years, new and more efficient engines have helped reduce air travel fuel consumption and harmful emissions. Experts say this is not enough, and, if left unchecked on its current fast paced growth trajectory, the amount of carbon from airplanes is projected to triple by 2050. While technology can theoretically assuage aviation demand growth and climate change mitigation, such reconciliation rests upon very ambitious and potentially unfeasible technological breakthroughs and optimistic assumptions on their ability to rapidly curb emissions.

Electric Air Travel — Coming to an Airport Near You Soon?

There are some significant challenges to using batteries for flight. Electric jets are more sci-fi than applied science right now, as aviation engineers are grappling with several difficult physics problems.

A battery’s efficiency, or ability to hold power, is measured in specific energy. Right now, even the best batteries have a specific energy of only 250 watt-hours per kilogram, but we have to get closer to 800 to really start flying, and that is still nothing compared to jet fuel’s specific energy, which is nearly 12,000 watt-hours per kilogram.

So you lose range because batteries, for the same amount of power, are so much heavier than fuel. Yet experts say that eliminating aviation’s impact on global warming means upending the industry through avenues like electric air travel. The longer that reality is evaded, the harder it will be to find effective solutions.

Uber is working on an electrical vertical takeoff and landing vehicle, or eVTOL, that could pick you up right at your house and fly you to an airport. Even big players like Airbus, Boeing, and Rolls-Royce are betting on this future.

Several aviation companies — from fledgling startups to industry titans and government agencies like NASA — are actively pursuing electric commercial planes in hopes of achieving carbon emissions-free flight. Around 215 types of electric-powered aircraft are currently being developed worldwide, and industry observers say electric airplanes will be commonplace before the end of the next decade.

Israeli company Eviation is producing an all-new electric plane for the regional market. The aircraft, known as Alice, has a range of 288 miles and can carry up to nine passengers. Eviation is making three variants, including commercial, executive, and eCargo.

In 2021, easyJet, Europe’s leading airline, welcomed the announcement by its partner Wright Electric on its engine development program for its flagship 186 seat electric aircraft, named Wright 1.

The Pipistrel Velis Electro, the first electric airplane to receive European Union flight certification. It is able to carry just two people, for only about an hour.

While innovative electric aircraft like these are making headlines, battery technology will have to advance a fair way in terms of both weight and storage to make large, commercial electric planes a reality. What gaps need to be filled?

• Aerospace players will need to step up R&D to develop lithium-ion batteries that are better suited for the higher gravimetric density needed in aerospace.
• Batteries that are lightweight yet powerful enough for smaller electrified planes will need to be suited for operating shorter ranges. Three or four times the weight of the airliner in batteries is required to be able to power it.
• Honeywell Aerospace says that, while battery technology matures, hybrid-electric aircraft will need both batteries and other power sources — like ultraefficient generators or fuel cells — to power the aircraft, recharge the batteries and improve aircraft safety, efficiency, and range.

It Will Take More than Electrifying Air Travel

A July, 2022 study in Nature concludes that switching to zero-carbon fuels would reduce CO2 removal requirements by up to 88{6932ee47e64f4ce8eedbbd5224581f6531cba18a35225771c06e4f1b3f0d9667} while switching early to zero-emissions aircraft would completely avoid the need for CO2 removal. Whereas zero-carbon fuels are experiencing rapid technological advances, despite still facing many economic challenges, zero-emissions airplanes that could replace current commercial aircraft are currently highly speculative due to constraints such as battery weight.

A 2021 open access letter in IOP argues that synthetic fuels, produced by 14–20 EJ of photovoltaic energy, would make it possible to completely phase out fossil fuels and to avoid emissions of up to 26.5 Gt CO2 over the period 2022–2050.

IATA lays out the industry proposal to fly net zero by 2050, which will require a combination of maximum elimination of emissions at the source, offsetting, and carbon capture technologies.

• 65{6932ee47e64f4ce8eedbbd5224581f6531cba18a35225771c06e4f1b3f0d9667} Sustainable aviation fuel
• 13{6932ee47e64f4ce8eedbbd5224581f6531cba18a35225771c06e4f1b3f0d9667} New technology, electric and hydrogen
• 3{6932ee47e64f4ce8eedbbd5224581f6531cba18a35225771c06e4f1b3f0d9667} Infrastructure and operational efficiencies
• 19{6932ee47e64f4ce8eedbbd5224581f6531cba18a35225771c06e4f1b3f0d9667} Offsets and carbon capture

The Air Transport Action Group offers an overview of the impact of air travel on climate pollution and economies.

• Worldwide, flights produced 915 million tons of CO2 in 2019. Globally, humans produced over 43 billion tons of CO2.
• In 2019, 4.5 billion passengers were carried by the world’s airlines.
• The global aviation industry produces around 2.1{6932ee47e64f4ce8eedbbd5224581f6531cba18a35225771c06e4f1b3f0d9667} of all human-induced carbon dioxide (CO2) emissions.
• Aviation is responsible for 12{6932ee47e64f4ce8eedbbd5224581f6531cba18a35225771c06e4f1b3f0d9667} of CO2 emissions from all transports sources, compared to 74{6932ee47e64f4ce8eedbbd5224581f6531cba18a35225771c06e4f1b3f0d9667} from road transport.
• While air transport carries around 1{6932ee47e64f4ce8eedbbd5224581f6531cba18a35225771c06e4f1b3f0d9667} of the volume of world trade shipments, it is over 35{6932ee47e64f4ce8eedbbd5224581f6531cba18a35225771c06e4f1b3f0d9667} by value – meaning that goods shipped by air are very high value commodities, often times perishable or time-sensitive.
• Jet aircraft in service today are well over 80{6932ee47e64f4ce8eedbbd5224581f6531cba18a35225771c06e4f1b3f0d9667} more fuel efficient per seat kilometer than the first jets in the 1960s.
• Alternative fuels, particularly sustainable aviation fuels (SAF), have been identified as excellent candidates for helping achieve the industry climate targets. SAF derived sources such as algae, jatropha, or waste by-products have been shown to reduce the carbon footprint of aviation fuel by up to 80{6932ee47e64f4ce8eedbbd5224581f6531cba18a35225771c06e4f1b3f0d9667} over their full lifecycle.
• Around 80{6932ee47e64f4ce8eedbbd5224581f6531cba18a35225771c06e4f1b3f0d9667} of aviation CO2 emissions are emitted from flights of over 1,500 kilometers, for which there is no practical alternative mode of transport.

The prospect of electric flight is appealing in many ways, especially in emissions reductions. A battery-powered plane charged with renewable energy could produce nearly 90{6932ee47e64f4ce8eedbbd5224581f6531cba18a35225771c06e4f1b3f0d9667} less in emissions than today’s planes that run on jet fuel.

Ultimately, the future of electric planes depends on the future of battery improvements.

Complete our 2022 CleanTechnica reader survey for a chance to win an electric bike.

Appreciate CleanTechnica’s originality and cleantech news coverage? Consider becoming a CleanTechnica Member, Supporter, Technician, or Ambassador — or a patron on Patreon.

Don’t want to miss a cleantech story? Sign up for daily news updates from CleanTechnica on email. Or follow us on Google News!

Have a tip for CleanTechnica, want to advertise, or want to suggest a guest for our CleanTech Talk podcast? Contact us here.