Carbon-free shipping. (Ed. – ammonia makes a very good aviation fuel)
Ammonia (NH3) could be used as a carbon free fuel for shipping. It could be made from atmospheric nitrogen combined with renewable energy derived hydrogen. Ammonia’s hydrogen could react with oxygen to power engines, turbines or fuel cells, emitting N and H2O. Oxygen pre-separation might be considered, instead of air, if it could raise energy conversion efficiency enough to warrant its use
Wikipedia’s http://en.wikipedia.org/wiki/Ammonia describes ammonia.
Hydrogen for ammonia synthesis should be obtained by electrolysis, rather than from methane. Apart from avoiding carbon dioxide emission, electrolytic hydrogen could avoid natural gas impurities which might harm fuel cells.
Compared with land-transport, ships should offer more space for ammonia safety features. With ammonia gas being lighter than air, leakage could be guided to high outlet vents. Storage tanks could be double walled with ammonia leak detectors between walls. Anhydrous ammonia could be stored under pressure as a liquid. It might be worth investigating strong ammonia aqueous solutions.
Ammonia powered shipping schemes could expedite domestic renewable energy deployment by mopping up surplus renewable energy generation at times of renewable energy over-supply, using planned redundant ammonia production and storage capacity. Stored ammonia could generate electricity when renewable energy supplies are low. Increased ammonia demand at overseas ports could encourage worldwide renewable energy deployment.