Fuel cells have been used to power data centers for years, with players including Apple, eBay, and Equinix all making big investments in the technology. But while most fuel cells power data center facilities from the outside, Microsoft just built a pilot data center with the fuel cells installed right on the racks. This is a shift that could radically simplify future data center infrastructure and improve energy efficiency in these energy-hungry facilities. The big investments noted above notwithstanding, fuel cells have only captured a small fraction of data center market share. New types of deployments like Microsoft’s data center could help drive fuel cells toward the segment’s mainstream.
A Unique Fuel Cell Application
The unique design routes natural gas piping directly to the server racks, which could help eliminate a significant amount of electrical wiring, gear, and controls typical to data centers. A photo from Microsoft’s blog post depicts at least five devices that appear to be fuel cells positioned atop the rack. At an assumed 5 kW-10 kW per rack, the 20 racks likely represent a load of 100 kW-200 kW. The deployment is a good fit for fuel cells since they can be readily scaled in size to match load. That is, a given system can add or remove individual cells or stacks to precisely match demand, a feat not possible with more monolithic alternatives like generator sets (gensets) or microturbines.
There are some potential challenges with this configuration. Installing that much fuel cell support infrastructure (exhaust flue, gas piping, and controls, etc.) could impose significant cost on installations, and maintenance on all those systems could be more taxing than on a single multi-megawatt system installed outdoors. And gas-powered systems generally face the challenge of gas grid outages. Though these are rarer than electric grid outages, they represent a concern—especially in seismic zones like those on the US West Coast. When an outage occurs, many data centers still rely on diesel backup generators since the fuel can be stored onsite. Despite these challenges, this type of deployment shows promise, thanks to ongoing fuel cell technology improvements and the low cost of natural gas.
New Players Enter the Arena
Microsoft mentions project partners McKinstry, a design-build construction firm, and Cummins, an engine and genset manufacturer. Though the fuel cell provider is not noted, Cummins teamed up with UK-based Ceres Power Holdings PLC to develop solid oxide fuel cells for data centers under a Department of Energy (DOE) award in 2016. The award specifies a minimum efficiency of 60% and a capacity of 5 kW scalable to 100 kW. That efficiency is slightly below the 65% (lower heating value) efficiency listed by Bloom Energy, which has largely dominated data center fuel cell deployments to date—though its systems are larger. Regardless of the approach, the high efficiency and consistent energy output of fuel cells is a good match for data centers at large.
While the current design operates on natural gas, a modified future system using pure hydrogen storage could help zero-carbon data centers incorporate intermittent renewable power. That is, the intermittency of renewables like solar PV has historically limited adoption on data center sites, which form a consistent load. If, however, that PV or wind system could generate hydrogen using an electrolyzer in a power-to-gas configuration, the energy could be stored to consistently power the data center via fuel cells. These types of innovations could represent a massive opportunity. According to Yole Développement, data centers used 1.6% of global power production in 2015 and are anticipated to grow to 1.9% in 2020. By any measure, the opportunities in this space loom large.
Tags: Distributed Natural Gas, Energy Technologies, Genset Manufacturers, Natural Gas, solar PV
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