Photograph courtesy Bloom Energy
Bloom Energy fuel cells are painted with patented inks, green on one side, black on the other. Photograph courtesy Bloom Energy.
Published February 24, 2010
Set to be unveiled today, the much anticipated Bloom Box—a residential "power plant" about the size of a mini-fridge—could provide cheap, environmentally friendly electricity to U.S. households within ten years, according to Bloom Energy, the company behind the fuel cell based invention.
But what, besides its hype, makes the Bloom Box special? Could it really revolutionize how we power our homes? And do Bloom Energy patents point to a secret killer app?
In an interview with CBS TV's 60 Minutes Sunday night, K.R. Sridhar, CEO of Bloom Energy, said that, for one thing, the Bloom Box fuel cell system is a much better, or at least more reliable, alternative to solar power as a green energy source.
Video: Bloom Box Segment From 60 Minutes
"The sun doesn't shine on your rooftop 24 hours a day," Sridhar said. "Our box produces electricity continually and reliably."
Fuel cells are devices that combine a fuel, such as natural gas, and an oxidant, such as oxygen, and turn their chemical energy directly into electrical energy.
Big Bloom Box Already in Use
For months now, Bloom Energy has been testing refrigerator-size Bloom Boxes at campuses of major corporations—including Google, FedEx, Wal-Mart, and eBay.
One of these jumbo Bloom Boxes, called Bloom Box Servers, could power a hundred homes, and four of them could power a 35,000-square-foot (3,250-square-meter) office building, Sridhar said on CBS.
Sridhar, a former NASA engineer, said he hopes to begin selling the mini-fridge-size Bloom Boxes within five to ten years. Each of the small Bloom Boxes should be able to power a household, he said.
How Bloom Box Works, Basically
At the heart of the Bloom Box are solid oxide fuel cells—in this case, flat, coaster-size ceramic plates with a secret coating—widely considered by experts to be one of the most efficient types of fuel cells.
A single Bloom Box plate can power one light bulb, but a stack of 64 of the cells could be "big enough to power a Starbucks," Sridhar said.
Oxygen and natural gas are fed into the Bloom Box and undergo a high-temperature chemical reaction in the fuel cells to produce electricity, heat, carbon dioxide, and water.
The fuel can be piped in from municipal natural gas systems—much as it is for gas stoves and ovens—or created from biogas or, as in the case of eBay, harvested from natural gas-rich landfills.
No Reason to Doubt Bloom Box Tech?
Friedrich "Fritz" Prinz, a fuel cell expert at Stanford University, said there's no reason to doubt that the Bloom Box works as Bloom Energy's Sridhar claims.
"The solid oxide fuel cell technology they're pursuing is one of the most attractive fuel cell technologies there is," said Prinz, who was not involved in the Bloom Box's development.
Based on the 60 Minutes segment, Prinz said, the design of the Bloom Box appears to be fairly standard and that there was nothing obviously revolutionary about it.
"They didn't reveal any new physics or any new principles, but I don't think they need to do that," Prinz added.
"They just need to take understood and recognized principles in material science and thermodynamics and implement them, and it looks like they've done that successfully.
"Whether they've done it economically, I don't know."
Bloom Box for the Budget Conscious?
The industrial-strength Bloom Boxes now in use cost eBay and other companies between U.S. $700,000 and $800,000. At eBay Bloom Energy is maintaining the machines under a ten-year maintenance contract.
eBay CEO John Donahoe told 60 Minutes that the five Bloom Boxes installed seven months ago at the company's campus in San Jose, California, now provide almost 15 percent of eBay's electricity needs. Estimated energy savings: $100,000.
At that rate, the Bloom Boxes should pay for themselves within three years, Donahoe told the business-news site Fast Company.
A residential Bloom Box should cost around U.S. $3,000, Sridhar said—much cheaper than most currently available consumer fuel cell systems.
"Manufacturing these things cheaply is not easy," said Michael Kanellos, editor-in-chief of Greentech Media, a business-news site specializing in green technology coverage and analysis. "ClearEdge initially sold theirs for $50,000, and they had to raise it to $56,000."
Those high prices are due in part to the fact that home fuel cell systems have been built by hand and because low demand hasn't allowed manufacturers to achieve economies of scale—for example to negotiate cheaper prices for raw materials in the way that large production runs allow—said Mike Brown, a vice president at fuel cell maker UTC Power.
Previous systems have also used the precious metal platinum, though Bloom Energy says they've found a way around this—though the details are under wraps—according to Prinz, of Stanford University.
Bloom Box Safe and Solid?
It's also unclear how safe and durable the Bloom Box will be, said UTC Power's Brown, a potential Bloom Energy competitor.
Solid oxide fuel cells must operate at extremely high temperatures, and as a result, they often crack or leak.
For the Bloom Box to become widely adopted by homeowners—who would presumably be nervous about replacing old reliable technology with a new, relatively untested one—the system will need an operational lifetime of about 85,000 hours, or about ten years, Brown said.
There are commercial fuel cells, such as ones made by UTC Power, that can operate continuously for that long, Brown said. Bloom Energy has not disclosed the operational lifetime of its Bloom Box.
It's also unclear as of yet how energy efficient the Bloom Boxes are, Brown said. Fuel cell systems in which both the generated electricity and heat are used can be 90 percent or more energy efficient.
Bloom Energy has not released specific details about the Bloom Box's energy efficiency or specified whether the heat produced by its units can be utilized.
"We didn't see any evidence of thermal recovery, so we assume it's an electricity-only device," Brown said. "If that's the case, it is somewhere between 45 and 55 percent electrically efficient."
That would make the Bloom Box only about 5 to 10 percent more efficient than conventional combined cycle gas turbine (CCGT) power plants, Brown said. Such plants create electricity in two phases: first via gas turbines, then via steam turbines, which take advantage of excess heat generated in the first phase.
Bloom Energy's Secret Killer App?
While most experts seem to agree that the Bloom Box appears to be a fairly standard solid oxide fuel cell system, the tiny power plant could hide a big secret.
Bloom Energy has filed patents in recent years that hint at a possible killer feature that could set its devices apart from the competition, Greentech Media's Kanellos said.
The patents describe a process for taking the runoff of the main electricity generation—carbon dioxide and water—and using it to produce oxygen and a "methane-like fuel," he said.
That new fuel and oxidant could be automatically run through the Bloom Box to generate even more electricity—and less waste.
If such a reverse-reaction is possible—and it's not clear that it is—then "it would be huge," Kanellos said.
"If they can do that, they're in a class by themselves," he said. "If they can't do that, then they just have a really nice fuel cell ... but it may not be so tremendously [different] to set them apart."
Feed the World
How do we feed nine billion people by 2050, and how do we do so sustainably?
We've made our magazine's best stories about the future of food available in a free iPad app.
Latest From Nat Geo
These cooing Casanovas use showstopping plumage to court females and fend off rivals.
Meet a trapper who keeps Florida's streets, sewers, and Kennedy Space Center alligator free.