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Fuel Cell Marvel "Bloom Box" Gaining Momentum
Many sources are continuing to excitedly report on the latest in a long line of startups chasing the holy grail of power sources. This incarnation, the "Bloom Box" from Bloom Energy, promises a power-plant-in-a-box that you can literally put in your backyard, and has received backing from companies like eBay, Google, Staples, FedEx, and Walmart. CBS recently aired an exclusive interview with K.R. Sridhar about his shiny new box. "So what is a Bloom Box exactly? Well, $700,000 to $800,000 will buy you a 'corporate sized' unit. Inside the box are a unique kind of fuel cell consisting of ceramic disks coated with green and black 'inks.' The inks somehow transform a stream of methane (or other hydrocarbons) and oxygen into power, when the box heats up to its operating temperature of 1,000 degrees Celsius. To get a view of the cost and benefits, eBay installed 5 of the boxes nine months ago. It says it has saved $100,000 USD on energy since."
These are solid oxide fuel cells (SOFCs). The catalyst is probably a little bit of nickel or some other fairly abundant metal. Platinum and/or palladium are needed as catalysts only for low temperature polymer electrolyte membrane (PEM) fuel cells.
Also, PEM fuel cells can be poisoned by carbon in the fuel stream. SOFCs can pretty easily oxidize CO and H2 and possibly even CH4 or C2H6 due to water-gas shift reactions.
IAA Mech Eng. I spent six years writing software to model both kinds of fuel cells.
This interested me enough to actually register (finally). There is a bunch of really horrendous media coverage on Fuel Cells in general but it doesn't help that in the article they mix concepts from different types of fuel cells, different types of "green energy" and general marketing.
Fuel cells that chemically transform reactants via an electrochemical reaction to products and release bunch electric energy directly along the way. You can think of it just like a battery that you keep putting more chemicals into. All fuel cells transform hydrogen and other hydrocarbons into electric energy with a little heat, all of them, they're solid state energy conversion devices not magical boxes. The big thing about solid oxide fuel cells is that they run at ridiculously high temps (600-1000C) so their reaction kinetics are tremendously faster than other kinds of fuel cells, they can self reform various fuels (natural gas, diesel, JP8, and they are tolerant to most containments (except usually sulfur and chromium).
However, the high temperature comes with a price, their interconnects degrade extraordinarily fast, sealing is a problem because of huge thermal expansion mismatches, and finally at 1000 degrees materials stability is a big problem.
As far as what they mentioned in the article, the "inks" are just catalyst layers, every fuel cell manufacturer and university uses those, everyone has their secret sauce. The "beach" is probably YSZ, or yttrium stabilized zirconia, which is the standard. The metal interconnects are coated with some conductive interconnects, no one would think of using platinum interconnects, they use that for catalysts on PEM fuel cells, it's totally unneccesary for SOFCS.
And if you're wondering, I'm doing graduate work on SOFCs, so we see this marketed crap in our field all the time, hopefully Bloom Energy has solved some of those problems I mentioned.
Other companies to check out: CFCL, Ceres Power