- Norway announced last year that the country wants all domestic flights to be electric by 2040.
- Beyond the hardware, electric aircraft stand to change airline business operations. Electric motors can allow for very short — even vertical — takeoff and landing, which means they don’t necessarily need an airport with huge runways. So rather than airlines, these aircraft could operate as air taxis.
- To compete on air routes up to 600 nautical miles in a Boeing 737- or Airbus A320-size airliner, Schäfer estimated that a battery would need to have a specific energy of 800 watt-hours per kilogram. Jet fuel, by comparison, has a specific energy of 11,890 watt-hours per kilogram. Right now, some of the best lithium-ion batteries have a specific energy of 250 watt-hours per kilogram, which has already proved viable in cars. While it would take a significantly more powerful battery to compete with a transcontinental airliner,
- The shorter routes are still a promising target. Sub-600 nautical mile flights represent about half of global departures, and they have an outsize environmental impact. “At very low distances, the dominating determinant of pollution is takeoff and climb,” Schäfer said. The energy required to get to altitude means airliners are less fuel-efficient in short flights. The efficiency per passenger gradually increases with the distance traveled, but it decreases again on long-haul trips since the aircraft also has to expend more energy to move the requisite fuel for the flight. That’s why most of the fuel use in aviation is still in long journeys. If all aircraft on short routes were electrified, it would only reduce aviation fuel use by 15 percent, according to the study.
- Battery energy densities have increased by 3 to 4 percent per year in recent years. If this trend continues, we’ll have an 800 watt-hour per kilogram battery by roughly the middle of the century, barring a breakthrough.