It could move goods, transport hydrogen, reduce CO2 and water the lawn all at once.
There are many reasons to be dubious about the hydrogen economy, and I've called it more of a folly than a fuel, but let's assume that you could make lots of it from surplus wind or solar power. Then you still have a problem of storage and transport. It is expensive to make it into liquid hydrogen; it leaks out like mad and it embrittles metal pipes.
However, a team at the International Institute for Applied Systems Analysis has a very interesting idea for killing a whole bunch of birds with one stone: Using the jet stream for sustainable airship and balloon transportation of cargo and hydrogen. They propose giant dirigibles to replace ocean-going ships that emit of CO2, particulates and NO2.
The airships would be filled with lots of hydrogen so that they could carry lots of freight, and would drift around the world at 10 to 20 Km altitude to catch a lift from the jet stream.
When it is time to descend, airships have to lose some lift, either by bleeding off some of the hydrogen or compressing it. But since a ton of hydrogen combines with oxygen to make nine tons of water, the researchers want to lose lift by making water and dropping it where it is needed. So the next time there is a drought in Georgia, instead of praying for rain, the governor can just order up a dirigible.
When our giant balloon full of hydrogen reaches its destination and offloads its cargo, all the hydrogen that lifted the cargo (about 80 percent of it) can be offloaded too, and then pumped into Toyotas or whatever other hydrogen vehicles there are. The much lighter dirigible can then return home for another load.
It's so clever; you get a valuable use for off-peak power, carbon free transport, snow in Georgia and a serious load of hydrogen. Lead researcher Julian Hunt summarises:
Airships have been used in the past and provided great services to society. Due to current needs, airships should be reconsidered and returned to the skies. Our paper presents results and arguments in favor of this. The development of an airship industry will reduce the costs of fast delivery cargo shipping, particularly in regions far from the coast. 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.
One wag noted: "Give us 100 years and $100 trillion dollars and we will provide you with a safe, sustainable, economically viable hydrogen economy." But perhaps with this fascinating thinking from Julian Hunt and his team, it might take a bit less time and money.