Fast Company

How Does the Bloom Box Energy Server Work?

Bloom Box

Now that the dust has started to settle on the unveiling of the Bloom Energy Server, we thought it might be useful to take a more detailed look at some of the technology behind the fuel cell-powered electricity generator.

  • The Bloom Energy Server is made out of fuel cells, or electrochemical cells. A single fuel cell consists of an anode, a cathode, and an electrolyte stuck between the two. As fuel flows in through the anode side and an oxidant comes in over the cathode, a reaction is triggered that causes electrons to move into the fuel cell's circuit, producing electricity.
  • The Bloom Energy Server isn't actually a server--that's just a PR buzzword. In actuality, it's a distributed power generator. Each "server" produces 100 kW of power, consists of thousands of fuel cells, costs between $700,000 and $800,000, and pays for itself in three to 5 years based on an energy cost of 8 to 9 cents per kW hour.
  • There are many different types of fuel cells. Some of the more popular ones include methanol fuel cells, hydrogen fuel cells, and zinc-air batteries. The Bloom Energy Server consists of solid oxide fuel cells, which are attractive because they can be made out of low-cost materials with high energy efficiencies.
  • The cells can run on a variety of fuels, including traditional fuel, natural gas, biomass gas, landfill gas, and ethanol.
  • Until now, technical challenges have stopped solid oxide fuel cells from being commercialized, but the company's cells ("sand" baked into ceramic squares that are coated with green and black inks) supposedly have overcome most of the issues. Bloom's Web site has a great animation showing how solid oxide fuel cells work.
  • Bloom Energy
  • One of the biggest problems with solid oxide fuel cells is their temperature requirement--the ceramic squares only become active at extremely high temperatures (up to 1800 F). That means Bloom's cells will have to prove that they can remain durable under the stress--already, the company has had to come out to replace cells at eBay's installation, which has been running for just 7 months. In general, Bloom expects that its fuel cell stacks will have to be switched out twice during the device's 10 year lifespan.
  • Bloom's device generates electricity at 50% to 55% conversion efficiency. In comparison, solar generally produces power at between 10% to 15% efficiency. But unlike solar panels, the Bloom Energy Server produces CO2 as a byproduct. According to the Energy Collective, "CO2 emissions when running on natural gas would be just under 0.8 pounds/kWh, which compares favorably to electricity from central station coal-fired plants (2 lbs/kWh) or natural gas plants (roughly 1.3 lbs/kWh) and the national average for on-grid electricity (around 1.3-1.5 lbs/kWh)." If the box runs on landfill gas or biogas, it produces net zero carbon emissions.
  • Eventually, Bloom hopes that a scaled-down version device can be used in homes. A residential Bloom Box would produce 1 kW of power and cost approximately $3,000. But that probably won't happen for at least 10 years.

Read more about Bloom Box:
Bloom Energy Unveils Its Ultra-Secretive Bloom Box Fuel Cell
eBay Opens Up About Installing Bloom Boxes and Their Room for Improvement
Is the Bloom Box Energy Server the Future of Plug and Play Electricity?
Could the Wondrous Bloom Box Power Your Alt-Fuel Car and Smartphone Too?

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  • Kevin Jackson

    Thank you Art Kns.
    It makes me angry when dumb reporters simply take the word of somebody trying to sell you something and reports it like it's factual.
    This, and many other products, particularly in the "green" field, are often presented as something great that will save the world when in fact it's a product that only makes sense when you have a company that wants a publicity stunt that makes them look like they "care" and receives monies the government, which it took from me and gets a big tax write-off for it (which means I have to pay more taxes to make up for that depreciation). Under these conditions does it matter if it works at all? I don't think so.
    The only positive thing I see in this situation is that a few big companies are proving (or dis-proving) a technology, but that's a small positive when I and millions of others have to, in part, pay for it.

  • amit kr

    Hi there!!

    I think that Bloom Energy is the answer of the future!! the fire that will benefit forever. Sadly, perhaps because Sridhar is an Indian; many reports and articles about Bloom server tend to have some nonsense. For example, temperatures like 800-1000 C are no uncommon in today's home and are regularly found in your cars, heaters, kitchens etc. But no one argues that they are harmful! Anyways; any science is built on previous efforts! But we should credit Shridhar and his teams for solving the perennial problems about fuel cells. For example its use of Platinum which made it very costly! Shridhar and team found a cheap replacement something which proved almost a dream for rest of us! Many other innovations were done and many more will be done!! Its adoption by Google, EBay and the likes is enough evidence of its viability!!

    LONG LIVE bLOOM Servers!!

  • delrio

    Plasma T.V is the biggest hoax of the century, someone has to pay for new tech. Let it be the large companies for a change. Bloom Servers if done correctly can change the direction of electric energy to the household.

  • Ed Zyburt

    I share your skepticism and the cost savings of the Bloom Servers. However, you forget that in California these companies receive a 25% incentive and a 30% incentive from the federal government. Giving a real cost of 45% of $700,000 - $800,000, $315,000 - $360,000.

    And when they fund these items they would do a long term loan for 20-30 years. Also, they will depreciate these Bloom Servers for the life of them (looks like 10 years) which takes off on their taxes. On a 10 year loan @ 4% on $315,000 would be 3,189.22/mo, 20 year would be 1,908.84/mo and 30 years would be 1,503.86.

    Electrical cost would be $6,570/mo on the grid.
    Natural Gas cost with Bloom Box $3,280/mo + $1,504/mo = $4,884/mo
    Now $4,884/mo is the cost out of pocket, however then depreciation on taxes of $315,000 - $50,000 for value in 10 years is $265,000. $265,000 / 10 years is $26,500 a year.
    Possible savings is $202,320 over 10 years.

    And the companies that are currently using them most likely paid cash for them.
    So, the savings is huge, $394,800 over 10 years. And most of them have 10-30 of these.

    So, for all big companies this is a huge savings.

    And 9 cent rate is on the high side.

  • Art Kns

    Hello, what am I missing here? Are you using some "new" math?

    How do you arrive at this statement:

    'Each "server" produces 100 Kw of power, consists of thousands
    of fuel cells, costs between $700,000 and $800,000, and pays
    for itself in three to 5 years based on an energy cost of 8
    to 9 cents per Kw hour.'

    There are only 730 hours per month so at 100% utilization (highly
    unlikely), a single unit would generate 73,000 Kwh of power worth
    $6,570 at the 9 cent rate. That's almost 10 years without a minute
    of downtime, zero fuel, zero maintenance or other operating costs
    and a zero interest acquisition loan!!! A three year payback would
    require a net savings of $20,800 per month - over three times the
    raw max output of the units. What are you smoking???

    I suspect that math is not your best subject but, com'on guys, this
    is just simple arithmetic!

    Assuming 90% utilization (optimistic), and subtracting only fuel
    costs of $2950 per month (see below), payback jumps to over 19
    years. Adding a token cost for maintenance of, say, $700 per month
    (less than 0.1% of unit cost and assuming that the expected (per
    Bloom), replacement of the fuel cells (twice in ten years), is
    covered by the warranty), leaves only $2260 for acquisition costs
    ($6570 * 90% - $2950 - $700). But a 10 year loan of $750K at only
    4% interest requires a $7600 monthly payment. How does a $5 grand
    monthly shortfall pay back anything let alone in 5 years???

    I'm all for technology, going green and energy independence but I
    don't see how this pencils out.


    Conversion units:
    1 Btu = 0.293 wh = 293 x 10^-6 Kwh
    1 cf ~= 1030 Btu (1010 to 1070 Btu/cf, depends on gas)
    1 MMBtu = 1 million (10^6) Btu
    1 ccf = 100 cf (cubic feet)

    Bloom specs:
    Output = 100Kw
    Input = 0.661 MMBtu/hr @ 100Kw (=> 6.42 ccf/hr @ 100Kw)
    Efficiency > 50%

    Fuel costs (natural gas):
    (0.661x10^6 Btu/hr) * (cf/1030 Btu) * (ccf/100cf) = 6.42 ccf/hr
    (730 hrs/mon) * (6.42 ccf/hr) * ($0.70/ccf) * 90% = $2950/mon

    Reality check - Efficiency:
    (0.661 MMBtu/hr) * (0.293 wh/Btu) * (Kwh/1000wh) = 194 Kwh
    (100 Kwh rating) / (194 Kwh gas input equivalent) = 52% efficiency

  • David Osedach

    Watch this turn out to be the hoax of the century. Untold millions invested in wortheless boxes of sand!