Electric Aircraft: the Solution to Sustainable Aviation Fuels

Commercial aviation is growing strongly, and with it, carbon emissions. However, in contrast to other modes of mobility (e.g., cars and ships), aviation has yet to significantly decrease carbon emissions or even show a solid agenda to replace fossil fuels altogether. That is why no industry currently focuses more on saving weight and reducing fuel consumption than commercial aviation. Sustainable aviation fuels are becoming an increasingly imperative topic, and eFuels seem viable for long-haul flights, but what about urban and regional (short-/mid-range) traffic? That’s where the rise of the electric aircraft industry comes in.

Electric aircraft are the answer when it comes to cutting down on growing emissions. Unfortunately, building these machines is difficult, and there are multiple ways to store and use electrical power. All of these methods come with big advantages and disadvantages, but all things considered, electric aircraft are still the future of aviation. As shown in the map below, it is already a busy place. The electric aviation space is full of innovation – manufacturers of brand-new designs, autonomy systems, passenger and cargo platforms, eCTOLs and eVTOLs, consulting, development and engineering, ground infrastructure, testing, and many more can be found driving this market segment.

Both eVTOLs and eCTOLs cater to very different demands for solving the issue of sustainable aviation. eVTOLs focus on urban applications where vertical takeoff and landing are essential (e.g., close to city centers). Meanwhile, eCTOLs focus on local airfields for regional transportation. Of course, there is an inevitable overlap between the two when it comes to short-haul regional transport, which makes this market development even more exciting.

eCTOLs are technically conventional aircraft powered by electric motors. Often, designs with eight or more engines/propellers can be found to optimize the flow over the wing (DEP) and increase flow efficiency while reducing noise. These aircraft are either designed new and from the ground up (e.g., Heart Aerospace, Elfly Group, Maeve Aerospace, Electra Aero, Zunum), or they are petrol-powered platforms that have been re-engineered to be powered electrically (e.g., Britten-Norman, Embraer, Ampaire, Pipistrel).

eVTOLs, on the other hand, are more than just electric helicopters. The goal of this electric aircraft design is ambitious: to reach net-zero platforms that are safer, quieter, less expensive, low-maintenance, and more efficient than conventional helicopters. Although these will initially be piloted, most manufacturers aim to offer fully automated flight operations in the future. The opportunity in this market segment is staggering. After record-breaking funding in 2021 and 2022, the leading manufacturers are now in the testing and certification phase before entering the market between 2025 and 2030.

Both eVTOLs and eCTOLs share a common challenge when it comes to flying electrically: the specific energy density (Wh/kg) of kerosene is hard to beat. Currently, three main categories of electric propulsion systems using sustainable fuels can be found in the eVTOL and eCTOL space: 1. Battery-electric, 2. Hydrogen-electric, and 3. Hybrid-electric.

All three systems have individual challenges regarding various topics, including energy production, storage, handling, temperature management, energy density, transformation, and sustainability. These challenges are addressed in multiple R&D projects worldwide, combining the best technical solutions currently on the market to create something genuinely new – and wildly disruptive.

Building and certifying an electric aircraft is not a simple task – especially when it comes with so many and such fundamental changes in design. Using an already certified airframe and adding electric propulsion systems (e.g., Ampirus, Whisper Aero, H55, MGM Compro, Zero Avia) can be a shortcut that some companies are taking. However, this solution to sustainable aviation fuels comes with an aged airframe design penalty. On the other hand, the process of designing, building, testing, and certifying an utterly new aircraft is very time- and money-consuming, yet it offers the chance to bring unmatched features to the market.

Very similarly to the use of new propulsion systems, the introduction of fully automated flights will fundamentally change the way that people and goods will be transported.

The weight of a pilot (incl. instruments, flight controls, safety systems) plays a big role, especially in the case of comparatively small platforms. Offering unpiloted flight operations increases payload capacity as well as range and significantly decreases costs and air risk. It’s a win-win-win situation, making it such an exciting solution to sustainable aviation fuels.

Some manufacturers are building systems to retrofit available aircraft with the ability to fly unpiloted (e.g., Merlin Lab, Reliable Robotics, Shadow Flight Labs, Xwing), while other manufacturers are building aircraft from the ground up, directly offering unpiloted flight when they hit the market (e.g., Wisk, Elroy Air, Dronamics, Pyka). Even though commercial aircraft today already fly 99% of the time automated, the crucial steps of takeoff, landing, and unforeseen developments (technical, meteorological, etc.) require swift human action.

Automating, testing, and certifying these abilities is a big challenge, which explains why most eVTOL and eCTOL manufacturers plan to certify piloted electric aircraft rather than unpiloted initially.

Finally, another challenge for sustainable aviation awaits – this time on the ground rather than in the air. Both electric aircraft types (eVTOLs and eCTOLs) require certain ground infrastructure features to increase their potential further.

eCTOLs can easily use existing regional airports or local airstrips, provided the required energy is available (e.g. kerosene, hydrogen, electrical power). This requires a good transportation infrastructure towards these airfields or the ability to generate those fuels on-site. Fortunately, many airfields already produce electrical energy using solar panels.

Given their target location and markets, eVTOLs face a much more significant challenge. Vertiports should ideally be located close to many paying customers (e.g., within cities). They also need to offer a certified TLOF (touch-down and lift-off) location, and they also require an energy supply. They will likely need to add additional value (beyond transportation) for the neighborhoods to increase acceptance rather than resistance. The energy supply alone might make operations close to city centers a real challenge, with electrical grids operating at their limit already.

So, Vertiports must also become a local energy hub to cater to the future high demand. Nevertheless, manufacturers like Skyports, Reef, Ferrovial, Urban-Air Port, and SkyScape have set off to face those challenges and enable urban and regional air travel.

The challenges for electric aircraft and solving the issue of electric aviation fuels, in general, are indeed many, but so are the opportunities. This current development is the most fundamental change in air transportation since the invention of the gas turbine. It is the gateway to a more quiet, efficient, and sustainable future of aviation. Cliché as this may sound at first, the rise of electric aircraft is, in fact, a game changer. Are all the questions answered yet? No. But sometimes, it’s essential to challenge the status quo and move into unknown territory to find new solutions, discover new opportunities, and fundamentally modify commercial aviation.