Scientific American: Five big alt-energy letdowns: Ideas that sounded good but ...

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http://www.sciam.com/blog/60-second-science/post.cfm?id=five-big-alt-energy-letdowns-ideas-2009-03-18

Mar 18, 2009 11:30 AM in Energy

Five big alt-energy letdowns: Ideas that sounded good but ...

By Katherine Harmon in 60-Second Science Blog

As the call for a clean energy savior – to wash away our fossil-fuel sins – grows louder, the number of questionable candidates swells. Should we be looking to photovoltaic or fusion? Turbines or tides? With thanks to readers who responded to our http://twitter.com/sciam">Twitter call for favorite alt-energy duds, here's a roundup of five ideas that may one day succeed, but aren't going to save the globe from a http://www.sciam.com/article.cfm?id=science-behind-climate-change">climate calamity any time soon.

Zero-point energy

Some have posited that looking to the very small – as in quantum – might help solve the very big global energy need. According to quantum mechanics, a perfect vacuum actually contains a bit of energy, which can create particles that pop into existence out of nowhere before quickly disappearing again. Physicists have seen this http://www.sciam.com/article.cfm?id=follow-up-what-is-the-zer">zero-point energy in the form of the http://www.sciam.com/article.cfm?id=what-is-the-casimir-effec">Casimir effect in which two closely spaced plates in a vacuum are pushed together ever so slightly. But one of the big problems would be capturing useful amounts of energy. Zero-point by definition is the very lowest level of energy (i.e. a vacuum), and getting the energy would depend on generating an even lower-level area – a feat that the thermodynamic system doesn't allow. Nevertheless, plenty of so-called "perpetual motion" devices using zero-point energy have been proposed, but careful analysis inevitably shows that such schemes violate at least one law of thermodynamics, and nothing concrete (or even too theoretically plausible) has materialized just yet.

Cold fusion

Also from the realm of the theoretically dubious, http://www.sciam.com/article.cfm?id=what-is-the-current-scien">cold fusion (or low energy nuclear reaction) has had a hazy history since it was first reported in 1989. The process, which allegedly created an unexpected burst of heat in an experiment by electrochemists Martin Fleischmann and Stanley Pons at the University of Utah, apparently occurred when some heavy water (water that contained extra hydrogen isotopes called deuterium), was zapped with electricity by an electrode made of palladium (a rare metal). So far it http://www.sciam.com/article.cfm?id=back-to-square-one">hasn't been replicated to satisfy either the scientific community or the Department of Energy, leaving this type of fusion's future out in the cold for now.

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What other questionable alternatives did we leave out? Let us know your favorite unsung (or unworthy) alternative energy ideas by commending below or tapping into our http://twitter.com/sciam">Twitter feed.