Hydrogen: the miracle fuel of the future?

Is hydrogen the solution to the world’s airborne challenges? Well, good luck. Yes, if you can get right down to it. And that’s a tough ask. Two years ago, the challenge was obvious –…

Hydrogen: the miracle fuel of the future?

Is hydrogen the solution to the world’s airborne challenges? Well, good luck.

Yes, if you can get right down to it. And that’s a tough ask.

Two years ago, the challenge was obvious — we were facing the problem of the world’s dependence on oil. We could easily produce hydrogen for our tanks, but the quantities needed were huge, and getting to the tank required a lengthy, pollution-filled journey from the source.

But there was hope. Nasa’s fuel cell demonstrator was cruising around, capable of powering an entire military plane and producing precious clean electricity and hydrogen on the way.

The challenge has changed. There are three key challenges: 1) How much energy can be generated from the fuel cell without burning or overheating? 2) How much hydrogen can be created? 3) How do we avoid, and can we avoid, the problems with transportation that keep people indoors more than ever?

For now, the answer is uncertain. The air force test fleet has notched up a total of six flights, but there is no reason to think the technology is ready for prime time.

The first indication that hydrogen is an airplane-friendly fuel came in 2008, when the Air Force announced that it would run long-distance tests of hydrogen as a power source, and a bi-country production accord was signed with Iceland Air.

The first hydrogen test plane was completed in 2010. It took three years to build, the two hydrogen tanks were identical to those for airline fuel, the hydrogen tanks were attached to the same airplane as the coke jet engines for an offset system, the hydrogen fuel was chemically identical to any jet fuel (think about that as an exciting thing), and the fuel was given off at the desired rate.

Back then, I compared the three major aerospace fuels (hydrogen, aviation kerosene and jet fuel) — and concluded that the ability to work with a fuel of the type and consistency demanded by commercial aviation would be ideal.

But when the test flight began — three years later — the fuel experienced an unacceptable increase in viscosity and the entire experiment had to be cancelled, the engine had suffered severe damage. The culprit was the separate tanks of the hydrogen fuel, which failed to meet the industry requirement of exactly spherical.

Luckily, there are some things we do know. One is that one (roughly spherical) hydrogen is needed for the aviation industry’s 2.5-3.5L lifetime — and that nearly 20% of the mass of that solution is hydrogen. Another is that the 50-year shelf life of a single tank is achievable — as long as we are able to separate the hydrogen from the fuel by an extensive, well-marked separation network.

The bigger challenge?

The tank must have room to hold hundreds of thousands of gallons of aviation fuel — and get down to the long distances required — without flaming or overheating.

It’s still somewhat speculative, but hydrogen can be readily made from water, air, solid matter, and carbon dioxide. In fuel cells, electrolysis of water-based fuels can be sufficient to store and maintain the required amounts. However, the consistency, viscosity and mass of the fuel will vary depending on where the fuel comes from. How much hydrogen there is and how much density it can store is the key variables. It’s been estimated that 200 million gallons of hydrogen is possible from one tanker.

Considering the potential complexity of the advanced fuel cell technology, it’s no surprise that it’s progressing at a snail’s pace. Not many companies have yet caught the hydrogen train, nor are many of them based in Washington. The United States is the second-largest user of oil, but very few companies outside of transport and carbon dioxide management offer viable solutions for the fight against oil dependency. And given the gas price, they aren’t likely to be around for long.

There are a few companies that are making decisions on whether to put in a pipeline or develop a hydrogen-powered station. And there’s an interesting endeavor underway — the Air Force and NASA, joined by China, are actively looking at ways to combine the two sides of the industry. While it will take a lot of time, money and research — it is certainly achievable.

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