Fuel cells and solar PV get all of the attention in the data center industry as alternatives to traditional electric utility service, though there are rumblings for combined heat and power (cogeneration) installs in the background.
Part and parcel of any discussion of primary power sources (including utility service) is backup generation. Sometimes that discussion includes relying on utility service as the backup, but I imagine that the UPS and diesel generator combo has ninety-nine percent plus market share.
I agree with the criticism of diesel generators up to a point - they of course produce emissions of pollutants and greenhouse gases when operated and tested, but with proper maintenance they are soundly reliable. Most backup generation failures that I've heard of (many at hospitals as well as at data centers) occur due to problems in switchgear, not the gen sets themselves.
But there is another reason I think that CommScope may be grasping at straws. They are positing a sixteen hour run time, using hydrogen fuel. From my days promoting alternate fuel vehicles, hydrogen storage was always an achilles heel. Costly. Leaky. Very high pressure.
Now utility natural gas service is not 100% reliable either, but it does have the advantage of being able to serve backup gen essentially continuously if needed. I tried to make the case that diesel gen sets should be converted to natural gas (easy to do; 15% diesel still used as a pilot fuel for ignition) for this reason, and because emissions would be dramatically lower, but have never seen that idea take hold.
This is not to say that there aren't data center operators out there willing to try new approaches. Google put the UPS on the server in the form of a battery, and Microsoft has looked at fuel cells at the rack level.
I'd like to see a head-to-head TCO comparison of diesel gen sets and fuel cells as backups, though regardless of the outcome, an operator is looking at the most expensive power he will ever use!