The actual cost of power varies widely across the US. Rick Siepka, Manager of Customer Service at Dominion Virginia Power, said that enterprise power rates are different than residential power rates. Residential power is typically charged only on power consumption. Enterprise rates are charged for consumption plus a fixed rate for the "Demand" connection. "Demand" is essentially a connection charge based upon the amount of energy that can be delivered to a site e.g. a data center that requires more than a 500 kilowatt demand. The total cost per kilowatt hour charges for the enterprise will vary. A single-shift operation with high demand will pay more per kilowatt-hour than the same "Demand" for a site that runs continuously 24 hours per day because the "Demand" cost is pro-rated over a longer day.
Siepka provided some interesting statistics about enterprise data center power consumption. About 50% of the IT infrastructure power bill is consumed operating equipment. About 43% of the power consumed in a data center is for cooling. The remaining energy costs include UPS losses, lighting and miscellaneous use. This means for every watt of equipment power, the enterprise has to budget another .86 watts of power to cool that equipment. He compared the power used for general office space at 16.4 kilowatt-hours per square foot per year with 575 kilowatt-hours per square foot per year for a data center. In other words, the data center consumes 35 times more power per square foot than the office.
It behooves the enterprise to carefully review their IT procurement strategies to see if the power consumption can be lowered by judicious equipment selection. This is a trade off of capital expense vs. operating expense and will lower the Total Cost of Ownership (TCO).
The blade server saturation in the racks has increased the power and air conditioning issues. Before 2001, most server racks had about 14 servers running off of 120v consuming 4 kilowatts (kW). By 2001, a rack contained about 42 servers running of 208v consuming 20kw. Today's blade server racks can require as much as 24kw per rack.
The blade server has been moving into VoIP and IP Telephony systems for years. NEBS3/ETSI IBM blade servers have been supporting about 100 service providers of VoIP services using Broadsoft software. The same server family is now used in 3Com, Siemens and Intecom IP Telephony systems for the entrprise. Alex Cabanes, Industry Marketing Manager of IBM's Systems and Technology Group, points out that the right server choice can reduce the blade server power requirments by 37%.
IBM has good white paper (PDF) prepared by IDC, "Solutions for the Datacenter's Thermal Challenges". Six of the conclusions in this paper are:
* While capital expenses for server hardware have moderated, operational expenses have escalated.
* Data centers at their power and cooling thresholds are unable to support new server deployments.
* Current environments do not provide optimal conversion of power and cooling into actual compute capacity.
* 40% of data center customers have reported that power demand has outstripped the current supply.
* It is common that IT managers do not know how much power their individual systems consume.
* There is often a planning/purchasing disconnect between the IT purchasers and the data center managers when it comes to purchasing IT equipment and its power consumption.
The Uptime Institute has a number of useful papers and reports on data center power issues. Here are some of the papers worth accessing at the Uptime site:
* "Data Center Energy Efficiency and Productivity" has a good discussion of the stakeholders and a Data Center Energy Efficiency and Productivity Index
* "Estimating Total Power Consumption by Servers in the US and the World"
* "The Invisible Crisis in the Data Center: The Economic Meltdown of Moore's Law" focuses on the TCO for operating blade servers.
* "2005-2010 Heat Density Trends in Data Processing Computer Systems and Telecommunications Equipment" that discusses the heat increase and the growing problem of hot spots.
Less of an energy issue for the VoIP/IPT systems is storage. Storage will mostly be for voice mail and archiving. As Unified Communications becomes more prevalent, then the storage usage will also increase. The changed E-Discovery rules (December 2006) will increase the storage requirements for the enterprise. It is expected that all forms of Unified Communications information will be candidates for long term storage.
There are now storage products for the data center that reduce the energy costs of storage. A good paper on the issue was written on this subject by Pund-It Research, "Power Conservation Inside and Outside the Box (PDF)." This is a vendor-specific document and should be read with that in mind. One of the conclusions is that with the right hardware and software combination, storage energy costs can be reduced by 33% to 67%.
Another resource for white papers on power and cooling is the American Power Conversion (APC-MGE) site. White papers # 43, # 46, # 49 and # 69, have valuable information on data center, closet and VoIP power and cooling issues.
Even though greening is a good social issue to support, greening in the data center can save real IT dollars. The power reduction can also look good in the organization's annual report.
