How do Bloom boxes get their fuel cell energy? And what types of emissions do Bloom Energy Servers give off?
Bloom Energy Servers such as the ES-5400 and ES-5700 can use either natural gas or directed biogas as fuel cell energy; both rely on methane as the fuel source. Although natural gas is a nonrenewable fossil fuel, it remains one of the least expensive and cleanest alternatives to combustion fuels such as coal or oil.
By comparison, biogas is a renewable, methane-rich gas produced from decay in swamps, marshes, landfills, sewage and, well, manure. Apple powers its Bloom servers with biogas from a landfill near its Maiden, N.C., data center.
Even though traditional combustion is not taking place, solid oxide fuel cell systems such as Bloom Energy Servers do produce emissions. Both Bloom units produce less than 0.01 pounds per megawatt hour (lb/mWh) of nitrogen oxide, 0.1 lb/mWh of carbon monoxide, and 0.02 lb/mWh of other volatile organic compounds. There is negligible sulfur oxide, but the units produce 773 lbs/mWh of carbon dioxide when using natural gas -- none when using biogas.
Data center operators considering fuel cell technologies such Bloom units should weigh the impact of these various carbon emissions on their total carbon footprint since it may factor into the calculation of carbon usage effectiveness or impact the determination of environmental carbon credits.
This was first published in May 2013