Hindenburg 2.0 — will the Airship return?
Transportation accounts for almost a quarter of all greenhouse gases emitted and marine cargo delivery is responsible for a substantial part. Because of our tightened climate goals and focus on sustainability, transportation industry is heading for zero-emissions. To reach those ambitious goals, innovation is needed and even abandoned technology combined with new materials might make the future. Airships or zeppelins were largely abandoned after the famous Hindenburg’s 1937 crash — but advanced materials might revive this flying giant.
Airships are aircraft that make use of the principle of buoyancy, by filling a large envelope with gas lighter than air. Usually, helium or hydrogen is used and provides most of the lift needed. Generally, airships can be distinguished into three types: non-rigid (also called a blimp), semi-rigid (partial supporting) and rigid structure (full supporting structure).
They provide several advantages in air-transport. Obviously, with a lighter-than-air vehicle, there is no need for fuel to maintain height. Also because of their low-speed maneuverability a small infrastructure is needed for starting and landing, while airplanes usually need a big runway to lift off. Another advantage is that airships are capable of lifting a big amount of cargo.
All these advantages come with the price of their size. Economically viable airships need a rather large size, which can go up to 2 kilometers in length. Such a big size creates a huge surface area and therefore high drag. As a matter of fact, the drag increases exponentially with increasing velocity. This does not only make airships vulnerable to weather but also limits their effective speed to 50–100kilometers per hour.
Obviously they can’t travel nearly as fast as commercial airplanes and are therefore useless for time-sensitive cargo or passenger flights. When it comes to general cargo transport though, airships can easily compete with marine transport.
Even though drag is limiting the speed of airships drastically, in special cases it can act as a useful boost. The jet stream is a core of strong winds traveling around the earth from west to east. Nowadays this stream is used for passenger flights of longer distances, but with the surface of airships, the jet stream would contribute most energy required to move the airship.
The spectacular burn of the Hindenburg, whose envelope and hydrogen filling caught fire, ended commercial airship travel at a stroke.
While the fear of putting a highly flammable gas in your vehicle in such a large volume is reasonable, there are some powerful advantages that helium can not overcome.
As mentioned above, either helium or hydrogen can be used as a filling gas. While helium is much safer to handle and provides almost as much lifting power as hydrogen it comes with a hefty price.
Hydrogen is a widely used industrial gas, that’s needed for all sorts of applications, while helium as a noble gas is only used in special ones. Thus it’s not only cheaper but being produced all around the world.
With the rise of a hydrogen society, due to the implementation of eco-fuels or hydrogen energy storage, the demand for H2 could increase dramatically in the next decades. Airships could play a key role in transporting hydrogen around the world. If, for example, an airship is shipping cargo from the USA to Europe it can passively transport the lifting gas. This works because once the airship reaches its destination, the cargo can be unloaded, which removes most of the weight. Hence only a fraction of hydrogen is needed for returning the ship.
Yet there a challenges to overcome: weather prediction is still not good enough to prevent all issues from happening, so wind and storm could create real problems for structures of such size. Even just building such a big rigid structure is challenging, not to speak of controlling the mechanics.
But if these problems could be overcome, a fleet of 1,125 airships “would be able to transport energy equivalent to 10% of current world electricity consumption.” (Popular Mechanics, 2019)
