Among the culprits are devices that suck power while not in use. I'm not sure how they arrived at this figure, but the U.S. Department of Energy estimates that, "in the average home, 75 percent of the electricity used to power home electronics is consumed while the products are turned off."
The government advises unplugging devices or using a power strip to turn them off, but this is sometimes inconvenient as it will disable remote controls and, in some cases, require the device to go through a time-consuming start-up.
Some devices are designed to run 24 hours a day. Digital video recorders, for example, are always standing-by to record your programs. About 18 months ago, I put an energy meter on some of the devices in my home and discovered that my TiVo was using 30 watts 24/7 and a Motorola Comcast PVR I was using at the time was sucking 40 watts, regardless of whether it was recording a program.
Little power bricks also consume electricity even when nothing is connected to them, so it's a good idea to unplug items like cell phone chargers and iPod chargers when not in use.
Many people leave their personal computers on 24 hours a day. If the machine successfully goes into sleep mode, the power drain is relatively low. But it's not uncommon, especially for Windows systems, for the machine to run at full-throttle when it should be sleeping.
If you do leave your machine turned on - even while at lunch - try to configure it to go into sleep or "stand-by" mode after, say, 15 or 20 minutes of inactivity.
In theory, it will wake up as soon as you touch the keyboard or move the mouse. Unfortunately, Windows sleep mode doesn't always work properly. Sometimes it fails to go into standby. And if it does fall asleep, it sometimes fails to wake up properly. There are a variety of reasons for this, including some software that demands full power. But often the culprit is one or more device drivers or USB devices that either fails to let the machine sleep or interferes with its ability to wake up.
Screen saver software does not save energy. It's much better to turn off your monitor when you take a break. CO2 Saver, a free program for Windows XP and Vista, can help you manage your PC's sleep behavior.
In my limited experience as a beta tester, Windows 7 seems to do a better job at sleeping and waking than Vista or Windows XP, but this is machine and software dependent. So until we see widespread deployment, we won't know if Microsoft has solved the problem. Mac OS X seems to be less prone to insomnia or failing to wake up, but it's not exempt from these problems.
PCs with ultra-fast processors and display adapters tend to use more power than somewhat slower systems. In general, notebook PCs are considerably more energy efficient than desktops, partially because they're designed to run on batteries and also because they have built-in screens that are powered from the same power supply as the rest of the machine. All-in-one desktops are generally more eco-friendly than machines with an external monitor.
Even though it doesn't affect your own power meter, the electrical demands of Internet services also add up. Every time you do something online, a server somewhere might have to access a hard drive while routers throughout the Internet are using energy to transmit the data that you're sending and receiving. I'm not suggesting you cut back on Internet use - just be aware that it's not carbon free.
And speaking of carbon, a McAfee-commissioned report issued last week by ICF International found that 62 trillion pieces of spam sent in 2008 had the same environmental impact as 3.1 million passenger cars or 2.4 million U.S. homes. A single piece of junk e-mail adds 0.3 grams of carbon dioxide, which is like driving three feet.
The ICF report estimates that e-mail from the average business user accounts for 288 pounds of carbon dioxide per year, with 22 percent of that usage related to spam. More than half the energy wasted by spam results from users viewing and deleting it, according to the report.
The process of getting spam from one place to another involves multiple phases - all of which consume energy. First, there is the scraping of Web sites to harvest e-mail addresses, followed by code and copy writing to initiate the spam campaign. Next comes sending the messages via the Internet to an army of infected "zombie PCs," all of which use energy to receive and retransmit the messages. Then there is the impact on servers that store and send the spam, the routers and other Internet infrastructure, and, of course, the PCs that finally receive and display the junk mail.
Add to that the resources used to attempt to filter the spam and it's easy to understand the potential environmental impact. If every in-box had spam filters, according to the report, we could cut energy waste by 75 percent. But eliminating spam at the source would save even more.
By Larry Magid