You know what they say: power corrupts. But a lack of power or inconsistent power — electrical power, that is — can corrupt your data or bring down your entire network. Your servers, your workstations, your routers and switches and just about every component of your network infrastructure are dependent on a reliable source of electricity. Some plug into an outlet (or, more often, a UPS or surge protector) directly. Others, such as some USB devices, draw their power from the computer to which they're attached. Either way, if the lights go out, all that high powered and expensive equipment is rendered useless.
Power to the people: not always a sure thing
Despite this obvious dependency, many IT infrastructure planners give little thought to the preservation and conservation of power beyond buying uninterruptible power supplies for the server room. Computer users may look for ways to tweak the power management settings on portables, in order to get the most out of a battery charge, but usually pay little attention to those same settings on desktop machines, leaving them at the defaults.
Dramatic increases in the per-kWh (kilowatt hour) rate that we're paying for electricity in the wake of the current oil crisis, along with the slap in the face of the reality of being without electricity that many faced after last year’s major hurricanes just might combine to cause companies and individuals to take power a little less for granted, though.
We get our electricity through the local/regional power grid, the network of transmission and distribution lines. The price you pay for electricity can vary tremendously depending on where you are, the company you use and the source of the energy. Electric companies that rely on natural gas to generate electricity, for instance, have raised prices far more than those that use hydroelectric power. Other sources of power generation include coal, nuclear energy and alternative sources such as solar and wind power.
In some markets, electricity is a deregulated utility and you have a choice among competitive companies. For example, in north central Texas, there are at least 15 companies offering residential service at prices differing as much as 3 cents per kWh. Businesses can negotiate with the retail electric providers. There are about 40 registered retail providers; some offer service only to small or medium-sized businesses, some only to large commercial enterprises.
Electricity prices are much lower in some areas. According to the Department of Energy, the average cost of residential electricity in the US is only 9.53 cents/kWh.
What’s it got to do with IT?
Regardless of your local energy prices, in most places the cost is going up and businesses are feeling the bite. Computer equipment contributes significantly to the amount of energy used. Most servers and network devices are left on 24/7, as are many workstations.
So how much electricity does a typical computer use? According to the Saving Electricity Web site, a typical desktop PC uses from 65 to 250 watts. Your power supply rating will tell you the maximum power usage (for example, 400 watts), but to accurately assess the usage of a particular system, you’ll need a watt-hour meter.
Doing the maths
To translate the wattage of a device to its electricity usage, you must consider how long it runs. If a computer uses 200 watts, it will use 1 kWh every five hours (five times 200 equals 1,000 watts or 1 kilowatt). If a device includes amperage information instead of wattage, you can find out the watts used by multiplying amps times voltage (voltage is usually 120 for a typical household type outlet). Once you have the kilowatt hours used per day, week, month or year, multiple by the power company’s rate per kWh to calculate how much it costs you to run the computer for that time period.
And remember that every peripheral device that plugs in also uses additional electricity. The average 17-inch CRT monitor uses 80 watts, while the same size LCD uses about 35. External hard drives, cable modems, powered speakers and so forth all use electricity. And while computers and network devices use a relatively small amount of electricity compared to some appliances, that cost adds up when you’re running dozens, hundreds or thousands of them throughout the company.
In addition, all these electronic devices, especially some high-powered servers, generate heat, and that means you’ll probably need to keep the air conditioning going more to cool them off. Air conditioners are some of the biggest power hogs with a 2.5 ton central A/C unit using 3,500 or more watts.
Creating your power-management strategy
Because the amount of money you spend on electricity to power your systems increases as your business grows and you add more computers, it’s important to come up with a strategy that will implement more energy-saving measures as usage increases. These can include:
- User education
- Equipment upgrades/replacement
- Formal written policies
- Technologically enforced policies
Users can be taught to turn off monitors when leaving the computer for any period of time (screen savers that display don’t save any energy), put their computers into hibernation or standby mode whenever they’re going to be away for more than a couple of minutes (coffee breaks, lunch), turn the computer and monitor off when they leave for the day if the system doesn’t need to be running for remote access or after-hours updates/upgrades. (It’s a common myth that it takes more energy to start backup than is used by running the computer overnight.)
Energy savings should be kept in mind when buying new equipment. Energy Star rated components use less power. Power strips that can turn off all components and peripherals at the same time make it more convenient for users to shut everything down at night and not forget some devices. LCD monitors use considerably less power than CRTs.
Formal written policies are more likely to be enforced than verbal suggestions or directives, and can carry penalties for violation. Policies should take into consideration different needs; for example, some computers may need to run all the time because they’re servers that need to be accessed or that perform monitoring or security tasks.
At the enterprise level, power management software is available that will allow you to monitor power distribution, multiple UPS health and other power components that support your mission critical applications. With Windows Vista, Microsoft has added the ability to control power management settings through Group Policy; for Windows XP and 2000 systems, third-party programs such as FullArmor can provide this functionality.
