"Hydrogen and air travel are a perfect match," Hugo Eckener once said. Well, we don't know if he actually spoke those words, but it's the kind of thing the chairman of the Zeppelin Company probably said all the time, at least until enthusiasm for the combination deflated along with the Hindenburg in May, 1937.
Such enthusiasm may take flight once again, if EasyJet makes good on a research project it announced this week. The UK's budget airline wants to use hydrogen fuel cells to power its aircraft as they taxi on the tarmac. The idea is to use a zero-emissions fuel rather than carbon-spewing, money-burning fossil fuels.
"We can actually power a green taxi system," says Ian Davies, EasyJet's head of engineering. Fuel cells combine a fuel---usually hydrogen---with oxygen to generate electricity without emissions or noise, and while they haven't quite caught on in cars yet, it's easy to see why the airline's interested: Anything that can cut fuel consumption---which accounts for a third of airline operating costs---is worth at least thinking about.
"Eliminating emissions and reducing fuel burn" are the obvious reasons for exploring these ideas, says Richard Aboulafia, an aviation analyst with the Teal Group. That's why Lufthansa has tested the "TaxiBot," an electric tow truck of sorts that would haul aircraft to the runway. And it's why Honeywell and Safran teamed up to create the "electric green taxiing system," which uses a plane's auxiliary power unit to run wheel-mounted motors. A study commissioned by the two companies found an electric taxiing system could cut fuel consumption by 51 percent compared to using a pair of engines to move around the tarmac. (EasyJet is collaborating with that effort, and Davies says hydrogen fuel cells could be used to power the whole thing.)
Hydrogen fuel cell taxiing is just an idea for now, so EasyJet hasn't provided many details. It says the "hydrogen cell container" would include batteries that store energy produced by the fuel cells, by kinetic energy recouped from the wheels (aka regenerative braking), and from photovoltaic cells. Pushing a 75-ton plane around an airport shouldn't be a problem, Davies says, since fuel cell systems already power things like buses and ferries.
Hydrogen power has struggled to reach the mainstream because of a few key reasons. Hydrogen may be the most abundant element in the universe, but it’s not so easily obtained. It’s commonly made by reformulating natural gas, its production can produce its own greenhouse gases, and there’s little delivery or fueling infrastructure to speak of. That's a big hurdle for hydrogen-powered cars, which would need a robust fueling infrastructure. But it's less of an issue for aviation, as the fuel could be delivered to a central depot.
EasyJet hopes to have a pilot program (forgive the pun) running this year, but given how slowly aviation innovation unfolds---Safran and Honeywell started on their system in 2011, it's not expected to be ready until 2018---don't expect to see it for yourself anytime soon.
