Hydrogen Air Taxis
Autonomous cars and electric aircraft have been the subject of a lot of hype, speculation, and funding in recent years. Perhaps something even more radical sounding would actually be more practical near term…
Problem
Many metropolitan areas are overrun with vehicle congestion that stymies the economy, reduces people’s happiness and productivity, and exacerbates carbon emissions. Electric autonomous cars may help alleviate some of these issues but face many technical and regulatory challenges to reach full level 5 autonomy given the number of complex edge cases of surface street driving (not to mention achieving such capability may only increase congestion). Electric aircraft on the other hand, introduce new modes of transportation and potentially an easier path to full autonomy (there are far fewer obstacles and edge cases in the sky) but batteries alone do not offer much flight time or up-time (with charging) to be practical for many applications.
Solution Vision
An autonomous fleet of electric multi-rotor aircraft powered by hydrogen fuel cells that move people and cargo around the densest trafficked metropolitan regions (~20-25 mile radius from city centers). The aircraft can leverage all of the electric motor, controls, and battery advancement of the last 10 years but its primary power source would be a hydrogen fuel cell and compressed hydrogen tank. Hydrogen is an ideal fuel for this application because when compressed to 10,000 psi (the pressure of the hydrogen tank in a Toyota Mirai), it has a specific energy (energy per unit mass) about 3X higher than jet fuel and 140X higher than lithium ion batteries. After factoring in a fuel cell efficiency of 50% vs a traditional helicopter turbine efficiency of maybe 20%, hydrogen becomes an obvious winner (not to mention zero engine noise and no particulate or emissions in dense cities). (Note: rotor noise would still need to be optimized based on rotor size, frequency, number, and placement)
While it may not seem intuitive, it is likely far safer to ride in an autonomous aircraft than an autonomous car. There are far fewer objects to collide with, more degrees of freedom to move, a far greater margin of error, and far fewer confounding variables to consider overall (surface conditions, traction, pedestrians, human drivers, and other forms of human error). In fact, the FAA is liable to approve such a concept far sooner than the NHTSA will approve a level 5 autonomous car.
A fleet of autonomous hydrogen air taxis could refuel at a small number of hydrogen hubs, minimizing the need for infrastructure build-out and enabling a low hydrogen price per kg. With sufficient range, such a fleet may even be able to refuel at the nearest zero carbon power plant; eliminating the need for hydrogen pipelines or trucking. While it is true that such a fleet could also be fueled by dirty hydrogen from existing steam methane reforming plants, the significant value margins for such a transportation service should hopefully dwarf the marginal cost of obtaining zero carbon hydrogen from electrolysis.
Business Model
Launch a fleet of autonomous hydrogen air taxis on pre-defined routes in the busiest cities (e.g. JFK to Manhattan, south bay to San Francisco, Los Angeles). Given that Uber currently offers a shared helicopter flight from JFK to Manhattan for around ~$100 (with the primary cost being the pilot), one could imagine many business professionals paying well over $100 to get anywhere around a city in 1/4 the time without risk of traffic. Eliminating the pilot may even drop this price to $50-$70 per trip and leave plenty of room for profit. Given the novel and contrarian nature of this idea, there may be need (and opportunity) for some level of vertical integration: building the hydrogen electrolysis infrastructure, building the aircraft, and operating the TNO service.