Fuel Cell Technology and Bloom Energy

After hearing State Representative Strama talk about the Bloom “Boxes,” I thought it would be interesting to research fuel cells and to compare the Bloom technology to the other technology out there.

A fuel cell is an electrochemical cell that converts a fuel source into electricity and water through reactions between a fuel and an oxidant triggered in the presence of an electrolyte.  Fuel cells are made up of three segments sandwiched together, an anode, electrolyte, and cathode.  Simply put, the anode oxidizes the fuel, turning the fuel into an ion and electron, the electrolyte allows the ion to pass through but not the electron, and at the cathode the ions are reunited with the electrons, which have passed through a wire to create the electrical current, and the two react with a third chemical to create water or carbon dioxide.

Fuel Cell Diagram

The most important features of a fuel cell are the electrolyte substance, which typically defines the type of fuel cell, the fuel that is used, the anode catalyst, and the cathode catalyst.

Bloom’s value proposition with fuel cell technology comes from the use of solid oxide fuel cells (SOFCs) which use low cost ceramic materials and have extremely high electrical efficiencies.  The challenge with SOFCs comes from the extremely high temperatures at which they operate, which gives them extremely high electrical efficiencies and fuel flexibility but creates engineering challenges.  Bloom claims to have solved these engineering challenges using breakthroughs in material sciences and a revolutionary design.  A detailed description of the Bloom fuel cell process can be found here.

The SOFC created by Bloom uses ceramic materials for the electrolyte whereas other types of fuel cells use, such as molten carbonate fuel cells, use more expensive materials.  Additionally, the SOFC can use a wide variety of fuels, as the Bloom Box runs on both natural gas and biogas, whereas most other fuel cells use only hydrogen.  This feature makes the Bloom Box more feasible as a solution for consumers as it will allow them to tie into an existing line in their home.  Finally, most fuel cells use precious metals such as platinum and nickel for the anode and cathodes, but Bloom uses special inks that coat the electrolyte which allows them to keep down costs.

Currently, Bloom offers an Energy Server that provides 100 kW of power from a device that is about the size of a standard parking space.  Considering the size and current cost of between $700,000 and $800,000, the energy server is feasible as an energy source for large businesses, such as Google, Wal-Mart, and Bank of America.  Additionally, it seems as though California subsidies has promoted the adoption of this technology, as 20% of the cost is subsidized by the state which is in addition to a 30% federal tax break.

As the technology improves, Bloom is estimating that they will offer an energy server to the residential market in 5-10 years for under $3,000.  It should be interesting to track the progress of this revolutionary company and to see if Bloom can deliver this promising product within the next decade.



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2 responses to “Fuel Cell Technology and Bloom Energy

  1. Ryan

    The Bloom Box certainly ramped up some hype, but for a while was light on the operating details. Fuel cells aren’t new, and neither really is the technology they have applied to operate at higher temperatures, but they have certainly scored with their marketing abilities.

    The Bloom Boxes use natural gas as a fuel, and unless they’ve reinvented chemistry and stoichiometry, these fuel cells still emit CO2, the same as any other natural gas power plant. However, if they operate at much higher efficiencies than typical natural gas plants then the net CO2 produced per kWh generated would be lower.

    Here’s a quick write-up on an existing natural gas combined cycle plant:

    This plant operates at a heat rate of 6,719 BTU/kWh, and had an installed capital cost of $555/kW.

    According to:

    the Bloom Box has a heat rate of 6,610 BTU/kWh, at the installed capital cost of at least $7000/kWh.

    That’s a 1.6% improvement in efficiency for a 1161% increase in price per kWh.

    While the Bloom Boxes certainly are pretty cool, and definitely have a much more compact footprint than a power plant, realistically they are reserved to the niche applications typical of fuel cells; places where size is more critical than cost or performance.

  2. bhgully

    Ryan’s comments also leads me to consider how systems such as these would be sanctioned under ongoing carbon legislation; although there is no telling, seems like allowances or permissible limits might be set to around the emissions rates of natural gas plants, and thus be similar for these. What is interesting is that once we start considering the marketing efforts to get these things to be household systems (with the obvious nod towards pricing) this would then bring the carbon legislation issue right into the back yard of the people (…that have Bloom Boxes).

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