A Key to Google's Data Center Efficiency: One Backup Battery Per Server

One of the geekiest, yet often obsessed-about, aspects of Google’s (s GOOG) innovations is its data centers. Up until recently, the company has been largely secretive about its data center technology and locations. But the search engine giant gave a rare glimpse today of how it’s using an on-board, lead-acid battery for each server in a data center to create a distributed backup power system. According to Google’s Ben Jai, who spoke at an event at the company’s campus this afternoon, the per-server battery system helps Google achieve an energy-efficiency rate for the backup power supply system of over 99.9 percent.

Data centers need a backup, uninterruptible power supply (UPS) so that if there’s a sudden power loss, the system can kick in until another power source (like a generator) comes online, making sure that web services don’t suffer outages. Keeping the power flowing to data centers can be crucial to a web business — a few years ago a power outage in San Francisco’s SOMA District shut down a data center, and the generators failed to come on, causing outages at web sites like Yelp, Technorati and Craigslist.

Traditional data centers have one centralized UPS room or area that starts up in the event of a power outage. The Google-designed battery-per-server setup is vastly different than the standard one and allows for a significant amount of power savings throughout the data center, in part because there are shorter connections to the backup power supply. Jai, who showed off one of the server-battery devices, said that a traditional UPS design has an efficiency of 92-95 percent, but Google can achieve close to 100 percent efficiency by using the distributed model. Jai said the distributed model is also significantly cheaper in capital costs than the centralized UPS design.

In the Q&A session after Jai’s talk, an executive from 365 Main (the company with the power outage issues we mentioned above) asked Jai and Google’s Chris Malone and Urs Hoelzle if server manufacturers had approached Google about manufacturing the on-board battery server design. Malone, Jai and Hoelzle said that Google had not pursued that as a source of revenue for the company, but that it has some patents for the on-board UPS that it might be interested in licensing. (photos of Google’s server-battery design coming shortly).