Earth Day 2008 will be celebrated on April 22 with observations scheduled around the world. This year’s theme is “A Call for Climate” a global warming action theme. While there may still be skeptics about global warning, there is no disputing the rising cost of energy, as I fill my Prius with $3.89 per gallon gas in California.  

In IT, the increasing demand for power and the cost of that power has quickly emerged as primary concerns, driving companies to take a closer look at the efficiencies of their data centers and of the IT infrastructures that they support. The United States Environmental Protection Agency (EPA) presented a report last August to the United States Congress which focused on IT data center energy usage and associated issues. This report noted that while data centers only accounted for 1.5% of energy consumption in the United States in 2006, they were a vital national asset and any disruption in availability of services would have severe consequences for business as well as national interests.  The report also estimated that this consumption would double by 2011. 

This report surveyed a number of data centers to track growth from 2000 to 2006 and found that 50% of the energy went into heating, ventilation, air conditioning (HVAC), power conditioning and distribution. The rest of the energy went into servers, storage, and network equipment. This was not surprising since most data centers were built 10 or more years ago. The last big data center construction boom occurred during the dot com boom in the late 1990’s. While energy costs were much lower then, we did experience energy shortages and brown outs in California where many service providers were located.  

As a result many companies will be building new energy efficient data centers over the next few years. In order to measure the efficiency of these new data centers, The Green Grid consortium has defined a data center power efficiency metric called PUE for Power Usage Efficiency. 

PUE is calculated by dividing the total power usage of a data center by the total power usage of the IT equipment. According to The Green Grid that ratio may be as high as 3.0, meaning for every watt that goes into IT equipment; 2 watts go into the data center infrastructure. The EPA study would suggest that this was closer to 2.0. PUE will also vary according to Data Center Tier, where Tier IV is the highest tier which supplies active/active redundant power supplies and supports less than 0.4 hours of annual IT down time due to site failure.  

As part of their CoolCenter50 initiative to reduce data center power 50%  in 5 years, Hitachi Ltd. issued a statement that they have set an aggressive PUE target of 1.6 for their new class IV data center in Yokohama, Japan. This data center is scheduled to be in production by April 2009 and will be architected to leverage the collective product innovations of the Hitachi Information and Technology Systems Group (ITSG) which includes storage systems, servers, and networking equipment and other key areas of Hitachi technology in thermal hydraulic cooling systems, uninterruptible power supplies, and power supply converters.  

While PUE is a relatively new metric, it is important to set targets and agree on metrics to measure progress in addressing energy as well as environmental issues. As we build out this data center, Hitachi expects to learn many lessons which we can apply to these issues.       

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