Would you believe that two brick-sized fuel cells could power an entire house cheaply — and with almost no carbon-dioxide emissions? Would you believe that every American house could be using these clean-energy generators to go off the grid "within five to 10 years?" Believe it, says K.R. Sridhar, CEO of the Sunnyvale, Calif.–based start-up that's producing the "Bloom Box." What is this mysterious box that everyone's talking about?

What does a Bloom Box look like?
Each box is a brick-size stack of thin ceramic plates that have been coated with a green and black ink Sridhar developed.

How does it work?
The individual ceramic plates in the stack act as fuel cells, creating energy through a chemical reaction between oxygen and a clean-energy fuel source such as natural gas or biofuels. Sridhar says two brick-sized stacks of these cells will power a typical U.S. home, while a single stack could power a smaller European home or several houses in a developing country. A stack of 64 cells will power a Starbucks.

How did Sridar invent this technology?
He says it began over a decade ago when he was employed by NASA to devise an oxygen-creation machine that could sustain life on Mars. After NASA scrapped his program, he reverse-engineered the device to produce energy. He says the entire development process cost "in the ballpark" of $400 million.

Sounds promising, but does the Bloom Box actually work?
It has reportedly been working splendidly — at least, on a grand scale — for months. Several large companies including FedEx, Google, Wal-Mart, and eBay, have been using refrigerator-size Bloom Boxes with encouraging results. EBay reports that it's saved $100,000 in energy costs since it started using five mega–Bloom Boxes last year. Google has been Blooming for 18 months. Still, skeptics like University of Washington chemist David Ginger say this existing data is short on technical details: "It is of the 'trust us, we're smart, this is revolutionary' nature."

So what's the real catch?
The price. Currently, these business-size units cost a hefty $700,000 to $800,000 a pop. Sridhar says he will eventually be able to get the price for a brick-size home unit down to $3,000. But will that be low enough? Bloom's biggest challenge, says GreenTech editor-in-chief Michael Kanellos, is making sure people don't "run away at the price tag." This technology "needs to be cheaper than solar. It needs to be cheaper than wind."

Is Sridar's forecast that we'll all own Bloom Boxes in 10 years realistic?
GreenTech's Kanellos predicts there's a 20 percent chance that we'll have Bloom Boxes in our homes in 20 years — but thinks that they'll be labeled "General Electric."

This article was originally published on February 23, then updated on August 31


Climate change: Time to eat Fido?
Nano: The world's cheapest car
Briefing: The hype - and hope - of clean coal
Green power's hidden agenda