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The latest renewable energy: Liquid air

Posting in Energy

A few years after asking "Why is there air?," Bill Cosby amused us with his Fat Albert shtick. Hey hey hey Bill, air can store energy.

The comedian Bill Cosby once asked, "Why is there air?" Today there's a new answer - to store energy.

Air, that invisible ampleness all around us, could hold on to energy from wind turbines that spin at night when we don't need the electricity, and then release it later, the BBC reports.

All you have to do is first turn the air into a liquid state, using technology adapted by a British company called Highview Power Storage.

Liquid air? Gulp! It might sound more suited for drowning, but it's just the sort of thing that ironically could help assure us an easier time of future breathing by curbing CO2-induced global warming and all its choking effects.

Highview uses night time electricity generated by wind turbines to chill air down to -190 degrees C (-310 degrees F), at which point it becomes liquid nitrogen. (I assume the process could also store excess daytime solar energy, although the BBC article only discusses wind).

Store that liquid in a giant vacuum, heat it back into a gas some other time, and the rush of air will drive a turbine. Feel good that renewable energy, not dirty old coal, will power your coffee maker in the morning. Except possibly for one thing - some external energy source has to help warm things up, and that source might not be renewable.

Another concern: At the moment, the process is only 25 percent efficient according to the article. I assume that means that it delivers only 25 percent of the electricity that it takes to liquify the air in the first place. That's better than nothing, but it obviously leaves room for improvement.

The Institution of Mechanical Engineers believes the process can hit 70 percent - not too far from the 80 percent delivered by batteries.

One technique that could help, according to IMechE: Locate the air chambers near industrial plants or conventional power stations, where waste heat will help warm the air. Note, though, that this probably relies on CO2-emitting fossil fuels powering those plants (until small nuclear reactors arrive to provide process heat, but that's another story). Nevertheless, it is effectively helping to cut down on their environmental impact.

Another trick: Run surplus chilled air through gravel that relinquishes coolness to assist in subsequent air cooling.

You have to admire the imaginative engineering, all of which derives from the work of Britain's Peter Dearman, who invented a liquid air engine to power vehicles, as you can see in this video of him and his cryo car:

Dearman believes that liquid air will trump other energy storage technologies because it does not rely on potentially scarce metals. Or, to paraphrase some other Brits - The Hollies - some time, all we'll need is the air that we breathe.

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Reader Advisory: Apologies for the wandering pop history today. From Bill Cosby to The Hollies. This story best read while wearing bell bottoms.

Photo: From Wikipedia, and not meant to imply any position by Mr. Cosby on liquid air or energy.

More air force:

Taking the heat on SmartPlanet:

— By on October 1, 2012, 8:52 PM PST

Mark Halper

Contributing Editor

Mark Halper has written for TIME, Fortune, Financial Times, the UK's Independent on Sunday, Forbes, New York Times, Wired, Variety and The Guardian. He is based in Bristol, U.K. Follow him on Twitter. Disclosure