Power Cost Savings in IT

Pay attention to the efficiency and usage of computers and peripherals, and you can save your company real money

If you were asked where the future of computers is, what would you answer? Redmond, Silicon Valley, maybe China? Would you believe Quincy, Washington—a town of 5,000 people halfway between Seattle and Spokane? Both Microsoft and Yahoo! plan to build large data centers (74 acres and 50 acres, respectively) in Quincy. Why? Because $0.018 per kilowatt hour with two hydroelectric power plants in Quincy's power district means cheap, reliable power. As the number of computers, servers, and other electrical peripherals grows, the cost and reliability of electricity is becoming a hot topic in IT. Unlike Microsoft or Yahoo!, you probably don't have the luxury of relocating your server room or (perhaps even better) your users next to a power plant, but you can affect the bottom line of your organization's power consumption.

Jump Start: Electricity Costs
We pay for electricity by the kilowatt-hour (kWh), which measures hourly consumption of electrical energy. One kilowatt equals 1000 watt-hours of electricity. A good way to understand these measurements is by considering the common incandescent light bulb. A 100-watt bulb uses 100 watt-hours of electricity in 60 minutes; thus, ten 100-watt light bulbs will use a combined total of 1kWh of electricity in an hour. In Quincy, businesses pay about 1.8 cents per kilowatt-hour; leaving ten 100-watt light bulbs on for an hour in Quincy costs a total of 1.8 cents. If you left those ten bulbs on 10 hours a day, 5 days a week, 52 weeks a year (i.e., 10 × 5 × 52) they would use a total 2600kWh, which in Quincy would run you about $46.80. By contrast, you'd pay about $300 for 2600kWh in northern California, or $195 at the 2005 national average for commercial sectors (i.e., 7.5 cents per kWh).

Most devices list wattage, but some list only their amperage (i.e., the strength of an electrical current measured in amperes, or amps). You can calculate wattage for these devices by multiplying their amps by their volts. Alternatively, for less than $200 you can buy a watt-hour meter, which calculates power usage for an electrical device you plug into it. Most high-end models will even let you download the power data to a computer.

Monitors: CRT or LCD?
In the not-too-distant future, cathode-ray tube (CRT) monitors and televisions will be relegated to 1980s science-fiction movies, but today, CRT monitors are still kicking around in many organizations. CRT monitors create their display by shooting an electron beam through a glass tube. They are high-voltage devices. By contrast, liquid crystal display (LCD) monitors shine fluorescent light through liquid crystals and glass. A typical 17" LCD monitor uses 35 watts, whereas a 17" CRT monitor uses 70 watts. Thus, the LCD display saves 50 percent in electricity costs over the CRT display. How much is that? You can use the following formula to determine annual cost:

Let's apply the formula to a CRT monitor that runs 8 hours a day, 5 days a week, 52 weeks a year, or 2080 hours per year, at an average cost for electricity of 7.5 cents per kWh:

Now, let's apply the formula to an LCD display with the same usage and cost figures:

Using an LCD display at the national average cost of electricity would save $5.46 per year in electric costs over the use of a CRT monitor. Additionally, because LCD displays give off very little heat, they can save as much as 50 percent in reduced air conditioning costs in most areas, making the total savings a bit higher. Clearly, savings in electricity alone might not convince a CFO to replace everyone's CRT monitors, but this formula is a good example of how you can compute electricity costs in IT.

Get Efficient
You might now be asking where you can save some real money. I'll give you the answer in two words: energy efficiency. (Yes, this was why your mom scolded you to turn off the lights when you left a room.) Take a look at Figure 1, which contrasts the power costs that the same computer can incur in two different usage scenarios. The computer is a common desktop model with a Pentium 4 processor and two hard disks; it uses a maximum of 175 watts, a minimum of 100 watts, and 4 watts while sleeping.

You can bring your energy costs down by purchasing more energy-efficient computers (examine the watt usage and support of advanced power configuration prior to purchase) and using them in an energy-conscious way. An excellent way to begin is to look for the ENERGY STAR logo. ENERGY STAR is a US government program that promotes energy efficiency and provides education about reducing energy consumption. You can find more information on the ENERGY STARWeb site at http://www.energystar.gov.

For computers running Windows 2000 and later, you can set the computer to turn the display or hard disks off for a defined period of inactivity and to switch the computer to standby or hibernate modes after a defined period of inactivity. These are relatively small changes that can save big money in a measurable way, as Figure 1 demonstrates. If you start a power-saving project in your organization, also take a look at replacing conventional light bulbs with energyefficient ones. The return on investment is tremendous—just do the math!

Add Up the Savings Energy
Energy conservation might not be the sexiest topic you'll ever encounter in IT. But by paying attention to the efficiency of your computers and peripherals and how they are used, you can save your company a lot of money.

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.