麻豆传媒

Editorial: 鈥�Look to the past for the fuel of the future鈥�

AS VITAL chemicals go, it鈥檚 hard to beat ammonia. Industrial production began in the early 20th century, and it played a key role in the second world war and in two Nobel prizes. It brought about a global revolution in agriculture 鈥� today, crops grown using ammonia-based fertilisers feed no less than . Could ammonia also be the clean fuel of the future?

When burned, it produces nothing more than water vapour and nitrogen, which makes up 78 per cent of Earth鈥檚 atmosphere. Earlier this year Italian tyre-maker Marangoni built an ammonia-gasoline hybrid automobile, the (see picture). The car can go for 178 kilometres on just one tank of ammonia. So can ammonia itself be made in a clean way?

Most ammonia is produced by heating natural gas or coal as a source of hydrogen, then forcing it to react with atmospheric nitrogen. It鈥檚 highly energy-intensive, accounting for between 2 and 3 per cent of the world鈥檚 energy budget and emitting over a billion tonnes of carbon each year in the process.

Now engineer John Holbrook has developed a technique he hopes will make the process cleaner. Instead of heating a fossil fuel, his technique, called solid state ammonia synthesis, works by drawing hydrogen out of water vapour through a charged membrane, and then reacting it with nitrogen.

Holbrook has co-founded to commercialise the technology. A prototype is being independently tested at in Richland, Washington. If it performs as expected, the final go-ahead will be given to a pilot ammonia plant in Juneau, Alaska, to take advantage of huge wind resources in a state powered by a patchwork of isolated microgrids. That will give remote communities a steady stream of power from their 鈥渟tranded鈥� renewables. Excess wind power will be used to produce ammonia 鈥� easily stored and distributed for burning later when wind is low.

鈥淭his will allow us to give Alaska鈥檚 energy islands 鈥� 150 of them 鈥� a degree of energy independence,鈥� says Bill Leighty of the environmental non-profit Leighty Foundation, who is leading the Juneau project. 鈥淭here is no energy grid in Alaska, and often no road system, so we probably can鈥檛 do this with electricity alone.鈥�

Other groups have already shown that it is possible to grab ammonia cleanly out of thin air. Using a different technique to Holbrook鈥檚, Mike Reese and researchers at the University of Minnesota this year to make ammonia. The group hopes to produce 25 tonnes of it by the end of the year and sell it as fertiliser to local farmers鈥� cooperatives.

Holbrook鈥檚 technique could be a big piece of the clean energy puzzle, alongside technologies like carbon-capture and storage, and nuclear, says Steve Wittrig of the Clean Air Task Force, a non-profit organisation based in Boston, who was previously the director of advanced technologies at BP. 鈥淎mmonia is not well known, but it鈥檚 one of the few places I鈥檝e looked that there is a really promising alternative being worked on,鈥� he says.

鈥淭here鈥檚 unlimited nitrogen in the air, and there鈥檚 unlimited water. You can see this scaling up to a global technology.鈥�

聯With unlimited nitrogen in the air, and unlimited water, you could turn it into a global technology聰