One focus of our data center design activities this week has been around the question of backup power. Any high-availability data center must face this question, and the reality is that there are not too many options to have a green approach to backup power.


The first consideration is the Uninterruptible Power Supply (UPS). We looked at three options for providing the immediate, on-demand UPS capability: traditional battery UPS, flywheel UPS, and Fuel Cell UPS.


The flywheel UPS seemed to provide the greenest option; however, it was not available to integrate with our chosen ‘pod’ manufacturer. This leaves us with the fuel cell or the battery options. While the Fuel Cell is a solid option for the future, I felt that the cost/benefit was not yet there for us. Which leaves us with a traditional battery for our UPS. Not the greenest option overall, but when you factor in the full APC Infrastruxure solution, we still come out ahead of the game.


The second major decision was on backup power to support the UPS for extended potential power failures. Most SMB data centers do not really face this issue. However, in the last two years of my tenure, we have had no fewer than three extended power outages that have taken down my data center for over 8 hours. Now that we’re running the SPRINTER train and the fare collection systems using the network, extended downtime is simply not an option.


We are therefore going to install an onsite generator. I initially was not happy with this idea because clearly a diesel generator is simply not green. We were initially pursuing a natural gas generator under the assumption that this would be a more environmentally-friendly option. However, in working with our generator installation firm (Bay City Electric), it became clear that natural gas would not be an option for us due to potential issues from earthquakes interrupting the supply lines.


So we’re going with the traditional diesel generator unless some other option presents itself. Our strategy will be to mitigate as many environmental concerns as possible through process:

  • Whenever possible, we will test the generator under load -meaning that we will run the data center 100% on the power the generator creates. This means that we will not be wasting the fuel.
  • We will install filtration on the emissions to ensure that we’re not discharging significant particulates
  • We will test as infrequently as possible to validate that the system in functional


I spent hours working with our IT firm Logicalis to try to find alternatives to these two decisions. I have to say that I am disappointed that there were not other options readily available in the market place for us. In reviewing some of the most successful green data center project case studies from the last two years, the preponderance of them make reference to their use of generators for backup power. Even my green-web hosting firm talks about their use of generators in times of need.


While we are making great strides on designing our green data center, I have to admit that I was disheartened with these two decisions I made in the design; however, I did not feel I had the business case, other case studies, nor the viable alternatives that would lead us down a different path.