Well, that didn't take long. Already analysts are crawling out of the woodwork to put the seemingly miraculous Bloom Box fuel cell in its place as yet another energy saving technology that won't perform as advertised.

This week it was IDC Energy Insights analyst Sam Jaffe, who said that while the fuel cell developed by Bloom Energy CEO K.R Sridhar and his team was definitely "not bogus," it just doesn't differentiate itself well enough from already available fuel cell technologies—especially as it pertains to price.

And the device's supposedly unique "fuel-switching" ability? Not unique at all, Jaffe claimed on his Energy Insight blog, in a post titled "Four Things Bloom Energy Forgot to Tell the World":

"Any high-temperature fuel cell should be able to do that. The fact that it's solid oxide and it's primarily ceramic opens up the possibility of making it much more cheaply, but every start-up in the energy field has an expensive product that they claim one day will be cheap. There is no reason to believe that Bloom has the ability to make it that much more cheaply. I'm pretty pessimistic about it."

Indeed. Further...fueling Jaffe's pessimism is the belief that a Bloom Box isn't really all that green if you're comparing it to the way we traditionally get power from the grid. At a cost of $7-$8/watt, he contends, the miracle box is no less expensive than photovoltaics that have been purchased at a rate of 100 kW at a time.

Another miracle energy tech bites the dust? Unless Bloom Energy can curb costs and green things up a bit, the answer for now is "maybe." Unless the unicorns get involved, anyway.

Still confused about fuel cells and the Bloom Box? Be sure to check out our regular Giz Explains column on this very topic! [IDC via CNET]