Could Giant Airships Replace Cargo Ships?
An international team of scientists primarily based out of the International Institute for Applied Systems Analysis (IIASA) in Vienna, Austria has painted a radical vision for the future of long-distance cargo and energy transport. In a new study published to the journal Energy Conversion and Management: X, they suggest that ginormous airships could compete with seafaring vessels for the transport of cargo and energy.
Why would this be desirable? Julian David Hunt, the lead author and a postdoctoral fellow in engineering at IIASA, argues that airships could perform the role of cargo ships faster and more sustainably in a future energy economy, one where hydrogen fuel has supplanted fossil fuels.
Hydrogen has attracted tons of attention as a potential fuel source because it is abundant, highly efficient when used in engines and fuel cells, emission-free, and can be sustainably produced from renewable energy sources.
In the new analysis, Hunt and his team propose that hydrogen-filled airships could sail the global jet streams – swift, consistent air currents caused by temperature differences between the poles and mid-latitudes – at altitudes of ten to fifteen kilometers, carrying cargo and hydrogen across vast distances drastically faster than seafaring ships. They estimate that a trip from Tokyo to Los Angeles would take an airship just four days, while a marine vessel voyage currently takes twenty.
These airships would be huge. Hunt envisions ships 2.4 kilometers-long – roughly eight times longer than the Hindenburg – carrying 3,300 tons of hydrogen in their balloons and another 21,000 tons of cargo. This cargo capacity is slightly less than a medium-sized modern container ship. Another variable to consider is cargo space volume, as modern container ships are typically compared by the number of twenty-foot containers they can carry. The authors didn't provide this number in their paper.
So is this grand vision even possible? There are a number of drawbacks standing in the way. For starters, this idea really only makes economic and environmental sense if hydrogen replaces other fossil fuel sources, which doesn't seem likely anytime soon. Moreover, the jet streams only run west to east, limiting the range and locations to which these airships could travel. Something as simple as docking could also be problematic due to airships' immense size, limited control mechanisms, and high wind drag. There's also the potentially catastrophic problem of explosion, as hydrogen is extremely combustible.
Hunt and his co-authors estimate that 1,125 airships completing 25 deliveries each per year could transport energy equivalent to 10% of the world's current electricity consumption.
"The possibility to transport hydrogen without the need to liquefy it would reduce the costs for the development of a sustainable and hydrogen based economy, ultimately increasing the feasibility of a 100% renewable world," Hunt says.
While this is a neat idea, it's one that will likely remain relegated to science fiction, at least in this century.
Source: J. David Hunt, E. Byers, A-L. Balogun, W. Leal Filho, A. Viviani Colling, A. Nascimento, Y. Wada, Using the jet stream for sustainable airship and balloon transportation of cargo and hydrogen, Energy Conversion and Management: X (2019), doi: https://doi.org/10.1016/j.ecmx.2019.100016