Electricity is a relatively cheap resource. And yet, why pay for something when you are not getting the benefit from using it? Surveys show that over 50% of computer systems are left running 24 hours, 7 days per week, 365 days per year.

The energy cost of running computers is both the cost of the electricity and - when necessary - the cost of cooling from the heat produced. For the sake of simplicity, this discussion focuses on the electricity consumed.

The electricity cost of running a single computer -- and keeping it running all the time -- is about $55.00 per year. This might not seem like a lot of money. For organizations with many computers, the costs can grow substantially.

Consider an organization with 1000 desktop and notebook systems. A thousand computers costs about $55,000.00 to run, per-year. With proper CPM in place, this number can be reduced by 75%, so that the electricity cost is around $13,000.00 per year.

This represents a savings of around $42,000.00 - per year.

Underlying Assumptions. Our calculations are based on the following:

• Electricity Cost - Our numbers assume a rate of 11.47 cents per kilowatt hour. This is average Residential Rate in the United States for the first half of 2009, as reported by the US Department of Energy. In that same time period, North Dakota (with 7.24 cents / kWh) had the lowest rates and Hawaii (with 22.89 cents / kWh) had the highest rates.
• Average Power Consumption - Our numbers assume that each system uses 55 Watts of electricity. This value was extrapolated from savings reported in a Wall Street Journal article for 50,000 desktop and notebook systems at DELL Computer. This seemed like a large enough sample for its average power consumption to be truly representative of large corporate use. (For details on the article, see the Wall Street Journal website.)
• Hours of Operation - The above numbers assume the computer is on for 2,080 hours per year. This is the number of hours put in by a full-time worker (40 hrs/week times 52 weeks/year). This is about one-quarter of the 8,760 hours, which is the time in 24 hours per day for 365 days.