Is Bloom Energy and its fuel cell server a friend or foe of the green data center? Today, the answer is very simple, but in the future it becomes more nuanced.

The Bloom Energy Server takes in a hydrogen-carrying fuel -- including natural gas, biogas, and even hydrogen -- and mixes it with oxygen and a bit of steam at high temperature to generate electricity, water, heat and a bit of carbon dioxide.  When it takes in natural gas, it generates some CO2, so it isn't carbon-free.

According to Bloom's specs, its latest ES5700 Energy Server generates 773 pounds of CO2 per megawatt hour (MWh) on natural gas.  Compare that to the U.S. Environmental Protection Agency (EPA) estimate of 1135 pounds of CO2 per MWh in traditional burning of natural gas and 2,249 lbs/MWh with coal and it's clear that Bloom's fuel cell beats coal and burned natural gas hands down when it comes to reducing CO2 emissions.  For a direct electrical substitute to reduce CO2 from fossil fuels, Bloom is a big winner.

Use of directed biogas -- cleaned up methane from rotting organic material pumped into existing natural gas pipelines -- puts Bloom electricity production into carbon-neutral territory and that's where life gets interesting.   Carbon-neutral does not equal carbon-free, so if you install a Bloom Energy cell and feed it biogas, you're going to reduce your carbon footprint if you're using coal or natural gas, but you're still putting CO2 into the atmosphere.  If you're looking to be able to sell carbon trading credits, I'll leave you to do the math.

Producing large quantities biogas to significantly impact the needs of society is still nascent territory.  Farms of all sizes are more concerned with waste management of manure and crop waste than turning it into energy and a potential profit center in the U.S., while Germany seems to have the lead in Europe for generating and using biogas.  Complicating matters is demand in transportation as a carbon-neutral substitute for natural gas.  Certainly, there's more biogas generation coming into the (figurative and literal) pipeline, but we're years before we see numbers above single digits in most countries.

Bloom Energy's fuel cell is carbon free if you feed it pure hydrogen, but that gets into the whole "How do we efficiently generate hydrogen?" question.  You can split water, but that requires electricity.  You can strip off the carbon from biogas, but that gets into using more energy.  There's also the possibility of using algae and other biological processes to generate hydrogen, but that is a journey to far-away possibility land rather than a near-term solution.

To summarize: Bloom Energy Server is a good -- but not a "best" -- solution in reducing carbon footprint, especially in regions that use coal, oil and/or natural gas-fired power plants.  It is carbon-neutral if used with biogas and can be carbon-free if you can feed it pure hydrogen.  If you're running a carbon-neutral or carbon-free data center already, a Bloom Energy-powered facility doesn't pose a threat to your "green" status.