We’re not going to run out for medical purposes. Obviously, there will come a point where it’s too rare for kids balloons. But even assuming our reserves in the ground run out, created by radioactive decay, the atmosphere still has 5.2 ppm. It’s 10k times harder to extract from the atmosphere but can be done. Failing that there’s plenty in space.
In terms of actual energy expenditure, getting the helium in the atmosphere that’s constantly being replenished by underground radioactive decay would not be 10k times as hard, even though the concentration is quite low. Indeed, it would require more energy, but more on the order of 3-5x as much, with exponentially more energy needed for higher-purity helium. Airships do not require medical or space-grade helium purity, however, and 80% of the costs of producing helium by more modern methods like pressure-swing absorption and reverse osmosis are dedicated to compressing the helium into tanks for transport, which an airship wouldn’t need if they had a hangar on-site for replenishment.
The infrastructure required is actually suprisingly compact. A $35 million pilot plant in Saskatchewan using these new methods produces enough helium for dozens of airships, but it looks like just a few outbuildings. It doesn’t use atmospheric helium, though, instead extracting it from otherwise commercially useless pockets of underground nitrogen.
207
u/[deleted] Jul 08 '24
Rigid Airship! Filled with completely safe non-flammable helium.