Current wisdom holds that oil will be hard to replace as the fuel of choice for transportation. But now the shipping industry is challenging that assumption. The number of ships powered by liquefied natural gas (LNG) instead of bunker fuel could increase 10-fold in the next five years as anti-pollution laws force owners to switch to cleaner-burning fuels, the world's biggest maker of marine engines has predicted. "LNG is the future for shipping," Jaakko Eskola, the head of ship power at the Finnish company , . He predicted that between 800 and 1,000 vessels might use the fuel by 2015, up from about 100 currently. Ships already using the fuel include offshore service ships, passenger ferries and LNG tankers. Wartsila is developing the world's first oil-products tanker designed to run on LNG. It is also working with the South Korean to design other large merchant ships that can run on the supercooled gas. Fitting ships to burn LNG costs roughly the same as installing equipment to remove oxides of sulphur and nitrogen, which are major pollutants, from the exhausts of ship engines running on heavy fuel oil, Mr Eskola said. Burning gas produces comparatively less pollution as well as lower carbon emissions. Another advantage is that it costs less than oil: about US$400 (Dh1,468) for a tonne of LNG in the UK, versus $495 for a tonne of fuel oil, according to Bloomberg data. The downside is that LNG-powered ships would require 40 per cent more storage space for LNG than for conventional fuel. But the cost of sacrificing potential cargo space would need to be weighed against the cost of extending the duration of voyages by slowing vessel speeds to cut fuel-use and emissions. That is a step that shippers including Japan's and the Danish are already taking. Ships currently burn between 200 million and 250 million tonnes per year of heavy fuel oil, according to the . Other approaches to reducing emissions of carbon dioxide and pollutants from ships include developing onboard nuclear propulsion units. A consortium of British, American and Greek interests have agreed to investigate "the practical maritime applications for small modular reactors" for tankers, recently . "We believe that as society recognises the limited choices available in the low-carbon, oil-scarce economy - and as land-based nuclear plants become common-place - we will see nuclear ships on specific trade routes sooner than many people currently anticipate," Richard Sadler, the CEO of Lloyd's Register, said at a signing ceremony in Athens. The consortium, consisting of Lloyd's, the US nuclear reactor developer , the British designer and the Greek ship operator , envisage ships powered by plug-in nuclear "batteries". The Asian container-ship operator is also reportedly considering nuclear-powered ships as one option for cutting emissions. About 10,000 carriers operate in so-called emission control areas, where the most stringent international pollution standards are being introduced more quickly than in other parts of the world, Mr Escola said.