Does Global Warming Help the Case for Airships?

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In the alternate worlds of steampunk fiction, glorious airships rule the skies, untroubled by lingering Hindenburg karma or pesky competition from other flying machines. One way that the television show Fringe flags scenes set in its heroes’ antagonistic parallel universe is by showing a New York skyline ornamented with passenger dirigibles (and a World Trade Center that never fell). Airships in our real world may not currently be much more than floating novelties, but enthusiasts for their technology have never given up on the dream of founding a new airship industry built around transporting people and cargo. Whether they can do so is debatable, but one factor that might tip the balance in their favor—perhaps unexpectedly—is climate change.

Last week, Txchnologist magazine published my story about efforts to bring back commercial airships. Many of the projects involve what are more accurately called hybrid airships. Helium inside their rigid or semi-rigid structures gives them some innate buoyancy (or static lift), but most of what holds them in up is aerodynamic lift from air rushing past their broad, flattened fuselages. These hybrids would also often use vertical thrusters to assist with takeoffs and landings, and ground-effect skirts (like hovercraft) as landing gear so that they could put down on either earth or water. (See my story for more details.)

For decades, the proponents of these hybrids and other airships have argued that they would offer huge advantages as cargo transports, particularly in places hard to serve easily or affordably by other means. Trains and trucks can move heavy loads efficiently but somebody has to build tracks and roadways for them to move on. Airfreight is fast but expensive, and somebody has to build runways and other support facilities at each end for the planes. Airships, according to this argument, could offer the best of both worlds: the ability to fly over undeveloped terrain at relatively low cost and to land in clearings rather than on groomed runways.

Artist's conception of a hybrid airship deployed above the Arctic circle. (Copyright © 2010 Hybrid Air Vehicles Ltd.)

The example that I’ve almost always heard cited as an application—going back at least to the late ‘70s or early ‘80s, when I first heard it discussed—is using airships to service isolated logging camps in the frozen north. No need to build trucking roads through the intervening difficult terrain at a cost that Barry Prentice, a professor of supply-chain management at the University of Manitoba, has pegged at roughly $1 million per kilometer. No need to disrupt the forests and other wild areas in between those remote sites and the rest of civilization. And given that the hybrid airships can often supposedly fly about three times or more times as far as comparable airplanes on a given amount of fuel, the airships would seemingly be the more environmentally friendly choice.

An argument that I hadn’t heard until recently, however, is that global warming may increase the pressure to find new sources of transportation into Arctic areas.

It’s the flip side of the observation that the disappearance of ice in the region is opening up new waterways suitable for shipping. What’s good for ships in this case is bad for trucks, particularly those traveling over the ice road system that serves communities and other sites in much of the north. When the ice thaws, the roads disappear. According to a 2007 paper by Prentice, cited by the Manitoba Chambers of Commerce:

Over the past 10 years, the [ice road transportation] network in Manitoba has gone from 55 to 60 days of usage to 20 days or less in some years.

A similar contraction of the ice road season is also evident further north in Alaska and the Northwest Territories. In 2006, the Northwest Territories diamond mines needed to airlift 20 per cent of their supplies because the ice road season ended early.

If we fast forward another decade or so, ice roads may not be worth building. How do the remote communities that depend on this transportation system obtain fuel, construction materials and food supplies?

Prentice argues that airships offer a potentially economical alternative to the Sisyphean task of building and maintaining roads. And analogous kinds of arguments can also be developed for deploying airships to sites in mountains, forests and other locations.

I love the idea of resurrecting airships, but my skepticism refuses to be put down easily. The same general arguments for airships have existed for decades, yet vehicles demonstrating their worth for the proposed jobs have never materialized. That fact doesn’t prove anything about airship technology’s viability, but it does make me wonder why businesses didn’t investigate the uses of airships more aggressively long ago if the economic case for them were so compelling.

It also makes me uncomfortable that most of the independent economic analyses favoring airships that I have been able to find in my research seem to lead back to the work by Prentice and his colleagues, or to papers several decades old. Very possibly I’m missing a large body of modern work on the subject, and I have no reason to think that Prentice’s analyses are wrong. Still, it makes me queasy if too many arguments for airships all balance on his work alone. (I’d be happy to be reassured on this point.)

Joseph A. Dick, an aviation consultant whom I quoted in my story and who wrote a piece about airships for ScientificAmerican.com this past May, is more deeply doubtful than I. He says that simple physical arguments first stated by the aeronautical engineering pioneer Theodore von Kármán in 1950 lead to the conclusion that airships move with too much friction relative to other vehicles of comparable speed. They therefore use more power than trains that are roughly as fast, and they are much slower than planes flying at comparable power consumption. That would suggest that airships don’t occupy a happy medium between cheap trains and expensive planes: rather, they’re stuck in an uncomfortably narrow niche.

Sources at companies working on hybrid airships whom I interviewed didn’t debunk Dick’s argument. They just pointed out that the airships under development are primarily aimed at specialized transportation niches where their advantages stand out. The hope is that once the vehicles have proved themselves in those situations, other uses will begin to emerge.

In the end, we most likely won’t know the truth until somebody really builds some of these new hybrid air vehicles and determines their actual performance and operational costs. I’m rooting for the new airship makers to succeed, but even if they fail, I’ll be glad to simply have an end to the speculative argument after so many decades.

Question for discussion: Technology is often very path dependent: innovations often succeed or fail because of historical developments rather than their intrinsic strengths or weaknesses. If we lived in a world where the Hindenburg never blew up, do you think that today we would already see airships handling these transportation jobs? Or is it more likely that the skeptics are right and that fundamental arguments based on economics and efficiency would have caused them to lose out to other forms of transportation in any case?

Respond in comments!

Further Reading:

Lead Zeppelin: Can Airships Overcome Past Disasters and Rise Again? by me, for Txchnologist.com (June 30, 2011).

Rebirth of Airships by Barry E. Prentice, Richard P. Beilock, Alfred J. Phillips, and Jim Thomson, in Journal of the Research Transportation Forum, vol. 44, no. 1 (Spring 2005), pages 173-190.

Airships and ice roads: Global warming forcing a re-think of how best to supply remote communities by Barry Prentice, for ISO Polar (Oct. 23, 2007)

2020 Manitoba Transportation Vision by Manitoba Transportation and Government Services

What Price Speed—Revisited by Imperial College’s Railway Research Group

Helium Hokum: Why Airships Will Never Be Part of Our Transportation Infrastructure by Joseph A. Dick, for ScientificAmerican.com (May 27, 2011)

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