The Hitchhiker’s Guide to Hydrogen
“Not all chemicals are bad. Without chemicals such as hydrogen and oxygen, for example, there would be no way to make water, a vital ingredient in beer.” – Dave Barry
On May 6, 1937, the German Zeppelin LZ-129 Hindenburg was on final approach for landing at Lakehurst, New Jersey. It was completing a cross-Atlantic journey from Germany and was running several hours behind schedule. Despite the delay, a large crowd of onlookers gathered to catch a glimpse of the iconic airship. As the Hindenburg dropped its landing lines to the ground crew waiting below, witnesses reported seeing a fire at the rear of the airship. Much to the horror of those assembled, the Hindenburg quickly crashed to the ground in a violent ball of flames. A total of 36 people were killed.
The Hindenburg disaster was a monumental cultural event. Herbert Morrison, then a 31-year-old radio reporter for WLS in Chicago, famously recorded his reactions in real time on an acetate disc. His dramatic description went viral. The incident spawned countless conspiracy theories, was the subject of many books and films, and even served as the naming inspiration for one of the greatest rock bands of all time, Led Zeppelin. Most relevant for our purposes, it also marked the end of the use of hydrogen in airships.
Airships are marvels of engineering. They leverage the buoyancy of certain gases (i.e., lighter than air) to provide lifting power. By pumping heavier air in and out of ballast tanks, pilots can lower or raise the equilibrium altitude at which neutral buoyancy is achieved. Toss in a diesel engine for propulsion and a rudder for steering and you have an incredibly simple and efficient way to move people and cargo across long distances. Prior to the Hindenburg accident, most airships were filled with hydrogen, a cheap and readily available buoyant gas. After the disaster, helium became the gas of choice. Although much rarer and more expensive than hydrogen, helium benefits from its inherent inertness – it is virtually unreactive under all but the most extreme conditions created in a laboratory.
The explosive reactivity of hydrogen laid bare by the Hindenburg calamity hints at its potential use in modern energy applications. Creating and controlling fires is at the heart of how humanity harnesses the forces of the universe in its endless battle against entropy, and anything as reactive and accessible as hydrogen gas can be a useful tool in the hands of the right engineers. Many environmentalists view hydrogen as indispensable to a carbon-free future, and in some narrow ways, their optimism is justified. But, like most aspects of our current energy debate, it is important to separate the hype from reality. What is the potential role of hydrogen in our energy mix, what are its real limitations, and under what circumstances could it serve as a foundational aspect of a truly carbon-free economy? Let’s dig in.