By Bjorn Fehrm
August 25, 2021, ©. Leeham News: Times change and the use of words with it. Today, the hundreds of UAM Air Taxi projects talk about how “environmentally friendly” this mode of transportation is, and Boom’s Overture is “the most Sustainable supersonic airliner.” The aerospace media recently focused on how we now have “Space Travel for everyone (in possession of the necessary pocket change).”
The head of Sustainable Aero Lab, Stephan Uhrenbacher, disqualifies these investments in a study on where to invest in fixing air transport’s pressing problems: “The startups receiving the most attention in aerospace recently have been doing space travel and urban air taxis. While these products make for exiting flying objects and satisfy human desire, neither air taxis nor putting more people in space address the problem facing commercial aviation: Flying needs to become carbon-free. And this needs to happen much faster than most people in the industry believe. It opens room for startups to provide components for future aircraft or even entire planes, but also new modes of operation.”
Figure 1. The promising Sustainable Aviation startups. Source: Sustainable Aero Lab.
What’s done to fix air transport’s real problem?
Projects seeking investments excel in presenting how “green” their innovative transportation method is—for example, air taxis:
- Just because the vehicle doesn’t produce CO2 directly doesn’t mean it’s environmentally friendly. Air Taxi is the most energy-intensive method of getting a person to an airport, many times worse than train, subway, bus, car, or ground taxi. And for the foreseeable future, this energy generation means the emission of greenhouse gases.
- Sustainable Aero Labs study also shows it’s capacity-wise a catastrophe (Study by Porsche consulting): https://www.sustainable.aero/mapping-sustainable-aviation-startups.
Yet air taxis are the darlings of the investment community, attracting billions of dollars in investment. The anti-pole, according to the Aero Lab study, is hydrogen investments, Figure 2, an area that can bring real change.
Figure 2. Hydrogen startup investments as a proportion of all Zero-emission investments. Source: Sustainable Aero Lab study.
These skewed investments, all falsely labeled as green, does little to help today’s pressing problem, our accelerating environmental problem.
Four areas worthy of investments
The Aero Lab study concludes four areas for greener air transport are worthy of investment (Figure 1):
- The Digital Backbone: Many steps in today’s airline operations are still handled by humans, yet they could be automated and optimized for greater efficiency to reduce fuel burn. More efficient flight routing can immediately lower emissions without any other changes. And the same efficiency improvement can reduce emissions at airports.
- Sustainable Aviation Fuel (SAF); offers enormous potential for reducing CO2 emissions in the short term. SAF has the potential to cut CO2 emissions across their lifecycle by up to 80% compared to fossil jet fuel, depending on the sustainable feedstock, production method, and airport supply chain. The production process needs a lot of innovation in the coming years, but the fuel is developed and works. The big advantage is there is no difference for current supply-chain operations.
- Electric (and Electric Hybrid Propulsion): While electrification is promising for other transport modes, it faces near-term challenges for air transport. Aviation demands high power outputs and high energy densities. It will limit electrified air transport to shorter haul operations for now. A larger impact in the short term is electrified ground transportation. Here solutions exist, and they work well (electric trains, tramways, buses, carts..).
- Hydrogen: it has the biggest potential for decarbonizing aviation over the next few decades. Unlike batteries, hydrogen just needs a top-up, so no recharging times, and as a technology, it’s lightweight. When fuel cells are available, they will also be emission-free; only water is produced together with energy. In the meantime, burning hydrogen in jet engines eliminates CO2 production and reduces NOx emissions five times. The hydrogen flip side is its challenging technology problems and that the tanks are light but space-intensive (hydrogen has three times more energy per kg but takes four times the space of today’s jet fuel).
Mentors help the startups
The idea of Sustainable Aero Lab is to not only help with investment in green aero tech but also to help the startups with advice. It has therefore recruited a group of industry Mentors, where your’s truly is one: https://www.sustainable.aero/mentors
The consulting to the startups is pro bono (i.e., free of charge). It’s a way for the mentors to give back to the industry their knowledge for a good cause.
In addition to personal mentoring of startups with their technology choices and investment applications, the lab arranges free masterclasses in aeronautical technology. So far classes in Electrical aviation and Aircraft development have been presented, https://www.sustainable.aero.