Tuesday, May 08, 2007

How much power does your PC consume?

The debate over global warming and who the culprits are on. The fingers are usually pointed to the cars who are burning away the fossil fuel and the industrial plants with their emission of toxic elements spreading both the sky and the soil.
However, a new culprit is in sight, hold your breath, it’s your very own personal computers. Is your computer a hazard to the environment? And what can you do to save the environment? Dibyajyoti Sarma finds out

When people think of climate change, they usually focus on cars or factories. Yet a study commissioned by chipmaker AMD has shown that 14 large-scale power production plants must run worldwide just to provide electricity to computer centres.
Then there are millions of PCs in private or corporate settings to be figured in as well. Not to mention the manufacture and disposal of the machines, all of which damage the environment.
User behaviour influences energy consumption. “That’s why you should always activate the energy saver functions,” recommends Mona Finder from Dena. This might turn the monitor off when the computer is not in use, for example. Animated screen savers are fossils from an earlier age of computing, she notes. "They just tend to use up energy, and they don't even save the screen."
It's difficult to put a firm number on how much energy, water, and raw materials go into PC manufacturing. It's been estimated that 15 kg of raw materials are needed for one processor, says Martin Hojsik from Greenpeace International in Bratislava, Slovakia.
It is clear, however, that valuable material is built into and around the PC: the metal casing in particular is of interest. "Metal is currently bringing in good prices," says Andreas Habel from the German Association for Secondary Raw Materials and Waste Disposal in Bonn. Some 1.87 million tonnes of electronic junk are produced each year in Germany, with IT scrap making up 114,000 of those tonnes.
The question of disposing old electronics is a tricky one. In some countries, the legal path is a clear one: old devices can be returned to the manufacturer free of charge or brought to community recycling centres. Yet this is still not a wonderful solution for the environment: even with the most modern of recycling technologies, a significant amount of material is sent to the landfills.
One important element for the environment is the reclamation of soft solder. The alloy is primarily used on the picture tube in monitors. In the past, monitors were simply put into landfills, leading to a situation in Habel's words where "40 percent of the lead contamination in landfills originates from old monitors."
Measured in terms of weight, 65 percent of each computer is brought back into the recycling chain. Yet one must also remember that the metal casing makes up most of a PC's weight. The recycling rate for metals in the electronic scrap pile amounts to more than 95 percent. Roughly 10 percent of the weight is used energetically, meaning that the material is burned.
Many manufacturers are seeking to lure customers with promises of computers produced in more environmentally friendly ways. Fujitsu-Siemens is offering a "Green PC," for example: "We’ve calculated that we require roughly 25 fewer sacks of coal to produce it than are needed for a traditional device," says marketing director Jorg Hartmann.
What can consumers do? Labels that stand for environmental friendliness also exist for PCs — perhaps too many, Hojsik finds: "I'm sceptical about how much these labels mean."
It's instead better to ask about a computer's production, consumption and disposal procedures before buying it in the first place, he says. Because computers grow out of date quickly, it makes sense to look for machines that can be upgraded.

Be on stand-by

Idle computers should be set to automatically switch into stand-by mode after extended periods of disuse. Stand-by mode protects the computer's components and helps them last longer.
It can also cut electricity costs, reports PC Professional magazine. Presuming one has an office computer that remains unused for three hours a day over the course of 225 working days a year, stand-by mode can save almost 100 kilowatt hours (kWh) in electricity, the Munich-based magazine has estimated.
The magazine recommends using the so-called S3 mode. That instructs the computer to store an image of the memory and processor register from the current session in the RAM. All components other than the RAM are then separated from the power supply. The system does not need to be rebooted during wake up, but instead restored to the last state from the memory.
The tests showed that the process lasted only six to 10 seconds. The alternative S4 mode works in a comparable way, although the system image is stored on the hard drive and the system is completely turned off. Waking up the system takes at least 20 seconds because it needs to be read from the hard drive, a slower process than reading from memory

Save energy

Switch of the monitor when the computer is not in use
If this is not possible, use the stand-by mode. A three-hours of stand-by when the computer is running 24 hours can save almost 100 kilowatt hours (kWh) in electricity
Try using the so-called S3 mode. That instructs the computer to store an image of the memory and processor register from the current session in the RAM. All components other than the RAM are then separated from the power supply. The system does not need to be rebooted during wake up, but instead restored to the last state from the memory
When your computer sleeps ("standby") it uses 1-6 watts, while the monitor uses next to nothing. You can set your computer to sleep automatically after a certain amount of idle time. Setting your computer to auto-sleep is the best and easiest way to save on computer energy use. In Windows XP go to Start > Control Panel > Power Options
Try to avoid animated screensavers. They are not the ‘in’ thing anyway. A screensaver that shows any image on the screen doesn't save any energy at all — you save energy only if the monitor goes dark by going into standby mode. If you turn the monitor off at the switch it will use 0 to 10 watts. (Some electronics equipment draws a small amount of power even when it's switched off.)
Laptop computers use about 15-45 watts, far less than desktops.
So set the Power settings on your computer to automatically go into Sleep/Standby mode after 15 minutes or so of inactivity. If you do nothing else, do this
If you use a desktop, use an LCD monitor. They use lots less energy than CRTs
Turn your computer off when you're done for the day
Use a laptop computer. They use lots less energy than desktops
Use a power strip so you can easily turn off all your computer accessories at once. BITS makes a special power strip that goes one step further, automatically cutting power to peripherals when you turn your computer off.

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