Another spurt of anti hydrogen stink was expelled in an article about so-called alternative fuels for air travel in today’s airliners written by Associated Press reporter Allison Linn. To her credit, she makes some object points about long standing interest in the aviation community in hydrogen.
Unfortunately, she could not resist the temptation to reference the fire which destroyed the Hindenburg in 1937. She failed to mention that most experts now believe the skin burned due to the coating’s uncanny chemical resemblance to gun powder which would have caused the loss of a helium filled Hindenburg as well.
Furthermore, had that same volume been filled with gasoline vapors at the point of ignition instead of hydrogen, the resulting catastrophic explosion would have likely killed everyone standing on the ground. That is only to illustrate that hydrogen contains less explosive energy by volume that gasoline, not that gas could be used in airships to lift the envelope. However, it does explain why diesel is used to power the motors on airships and not gasoline.
On the topic of hydrogen as a feasible energy carrier or airline fuel, the facts are fairly simple and straight forward. Early adoption of hydrogen fuel requires high value, pollution-sensitive applications where little new infrastructure is required.
Airline travel does meet these criteria perfectly but there is significant economic sensitivity and regulatory complexity in implementing the hydrogen solution. Airliners, like buses, stop at specific destinations thus fueling stations located at airports, including on-site reforming of natural gas or water electrolysis, let alone delivery by pipeline or tanker, require less infrastructure than hydrogen powered cars.
The airline industry is also facing increasing pressure to further reduce the impact of its jet engine emissions, both the main propulsion systems and auxiliary powerplants or APUs. Hydrogen can be “burned” in these gas turbine engines with zero carbon output and low levels of nitrogen oxides (NOX). If fuel cell technology proves viable the fans of fan jet engines could be spun by electric motors powered by PEM fuel cells which would turn airliners into zero emission transportation systems.
Storage remains a challenge, especially for the very weight and volume sensitive airline industry. Cryogenic storage looks like the most viable initial path with relatively light weight very high pressure carbon fiber compressed gas tanks in the 10,000 psi plus range to follow.
All fuels contain energy and hydrogen is no exception, so safety remains a normal concern. In some respects it is arguably safer than Jet A. Unlike Jet A, it will not poison you if you breath it in (short of suffocation) or inhale the exhaust by-products. And unlike Jet A, in the event of a crash and rupture of the tanks, hydrogen, both liquid and gaseous, will dissipate quickly into the surrounding air reducing the chance of a post crash fire due to fuel, if it has not already begun. And those wafts of hydrogen? Non polluting, of course.