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Give Your Computer a Rest Featured on Jan 29, 2010
Challenge
Unplug your computer every night for one month. Unless it's unplugged, your idle PC still uses electricity.
Individual Result
By unplugging your PC each night for a month, you will reduce your CO2 emissions by a total of 51 lbs. and your electric bill by $3.30.
Rally Impact
8758 people have reduced CO2 emissions by 219.37 tons by completing this challenge so far. That's equal to turning off the electricity of 237 homes for about 1 month!
Join Carbonrally at Green:Net 2010. Click below for $90 discount
Challenge Details
Rallyer-powered! This was the first Challenge soured from the Challenge Workshop. This first Rallyer-inspired Challenge was based on terrific electricity-saving suggestions from Bee and several others. Nice work Bee! Now, get ready to stand up and power down… your computers.
The Carbon Connection
You’re reading this on a computer, aren’t you? As you sit there, basking in the glow of Carbonrally, are you thinking about how much carbon dioxide is being created to keep your PC running? Every time you power up your computer, you’re drawing electricity from the nearest power plant which is probably powered by coal, oil, or natural gas. And burning fossil fuels produces carbon dioxide.
So our first message is to turn off your computer when you won’t be using it for a long period of time. An average desktop computer with a 17-inch monitor needs between 150 and 350 watts of electricity while it is being activity used. If you were to leave that computer on 24 hours a day, 365 days a year, it would use over $200 of electricity and lead to the release of over 1.5 tons of CO2 into Earth’s atmosphere. Turning off your computer even an inactive computer for just 10 hours a day can lead to substantial carbon savings.
However, this Rallyer-inspired Challenge asks you to go the extra distance. Did you know that many of your household electronics and appliances use electricity even when they are turned off? This is known as standby or “phantom” power. For instance, your television uses standby power so that it can be ready to instantly turn on when you click the remote control. Your computer’s printer powers down, but isn’t really off unless you turn off its power switch or unplug it. Anything you own that has a transformer plugged into a socket is probably drawing electricity all the time, even when the gadget it’s connected to is not in use. Skeptical? Touch the transformer. If it is warm to the touch, then it’s wasting electricity.
At a few watts here and a few watts there, this loss of “phantom” power really begins to add up. In the United States, an estimated 5% of residential electricity is used as “phantom” power. According to the Department of Energy, that wasted 5% amounts to an annual energy loss of 64 million megawatt-hours of electricity an amount of energy equivalent to the output of 18 typical power stations and at a cost of over $3 billion. If we could stop the use of all that “phantom” power, we could keep 100 billion pounds of CO2 out of Earth’s atmosphere each year.
So, for this Challenge, it isn’t enough to simply let your computer system hibernate overnight or even to turn it off. A computer and monitor that are both in “sleep mode” can still use anywhere between 8 and 28 watts of power. The only way to stop them from using any electricity at all is to cut the cord. Not literally, of course. Unplugging them will do.
Getting It Done
Need help meeting this Challenge? Here are a few simple suggestions:
- One easy way to make sure you’re not wasting energy is to plug your computer, monitor, printer, and any other computer peripherals you have into a single power strip. After you shut the computer down, you can effectively unplug it and all the other pieces by turning off the power strip. That’s a lot easier than unplugging everything individually and plugging them back in the next morning. Just turn the power strip back on and restart the computer.
- Better yet, you could buy a “Smart Strip” power strip for around $30. The “Smart Strip” essentially monitors electricity use in each plug and shuts off the ones that have been idle for a period of time.
- Even if you’ve decided to accept our Challenge and unplug your computer every night, you could still benefit from understanding your computer’s built-in power savings options. For instance, under Vista’s new hybrid sleep mode, you can put your computer to sleep while you’re out to lunch or in a meeting. While you’re away, your computer will only be using 2 or 3 watts of electricity. And, better yet, when you return, it will start back up in seconds with everything just as you left it. Read more about Vista and Mac power-saving options.
- There are a few common sense warnings to this Challenge. Be sure that your computer is set up to do important housekeeping chores (e.g., scanning for viruses or adware, downloading and installing critical updates, backing up your files) at a time when your computer is plugged in and turned on. Also, consider leaving your cable modem and network router plugged in. Sometimes they can be a little finicky about restarting, grabbing an IP address, and so on.
Do you have any other suggestions about how to make it easier for Rallyers and their friends to turn off and unplug their computers? If so, please share them in the Challenge forum section below.
Rules of the Challenge
The duration of this Challenge is one month and the Challenge is repeatable. If you accept this Challenge, you’ll see 1.7 lbs. of CO2 reduction added to your Rally account each day for the next month.
Are you someone who normally leaves his computer on all day? Does it run all night with a screensaver, or with the CPU running and the monitor turned off? We’ll make you a deal. For the first month of the Challenge, you can start with setting your computer up to hibernate or sleep at night. That will save 90% of the electricity you would have been wasting. And if, in that first month, you see that this isn’t such a big deal, then next month you can repeat this Challenge, buy a smart power strip, and shut your computer down completely overnight.
Learn More
Climate Savers: Computing Power Management Tips
Wikipedia: Standby Power
Grist: Smart Power Strips
When to Turn Off Personal Computers
Mr. Electricity: Saving Electricity
Estimating Appliance and Home Electronic Energy Use
See the Math
We know your computer is probably different from your brother’s or your professor’s or that girl with the Mac you met at the coffee shop. For the purposes of this Challenge, we are going to make the following assumptions to calculate an average value for your computer’s energy consumption:
- We assume that 60% of you are using a desktop computer and 40% are using laptops/notebooks. We also assume 50% of all computers are connected to laser or inkjet printers. For the purposes of simplicity, we are ignoring any other peripherals you may have attached to your computer (e.g., scanner, external hard drives, speakers). That doesn’t mean don’t unplug them! We’re just not including them in our calculations.
- For our desktop systems, we are imagining a desktop computer with a 17-inch external monitor. That system, including the computer and monitor, uses 200 watts when it is turned on and inactive.
- We assume a laptop/notebook without an external monitor uses only about 40 watts.
- We assume laser or inkjet printers consume an average of around 4 watts in standby mode.
- We assume that you are unplugging your computer for 10 hours per day. That should be a conservative number. If it isn’t, you need to get out more.
- The Challenge lasts for a month. Let’s call a month 30 days. So, taking this Challenge results in 300 hours of savings per month (30 days at 10 hours unplugged per day).
- A kilowatt is equal to 1000 watts. Using 1 kilowatt for 1 hour is what your electric company describes as 1 kilowatt-hour (kWh).
- So, let’s first look at just the electricity savings by our desktop users. Using the above numbers gives us:

Desktop users taking this Challenge reduce electricity used by 60 kWh per month. Using a similar formula, we find that laptop users save 12 kWh per month. Rallyers with printers save another 1.2 kWh per month. - Now we need to get to an average Rallyer’s savings. So we are going to apply the percentages of each type of user to the savings to get a weighted average. Desktop users (60% of you) save 60 kWh (60 kWh x 60% = 36 kWh). Laptop users (40% of you) save 12 kWh (12 kWh x 40% = 4.8 kWh). And users of printers (50%) save 1.2 kWh (1.2 kWh x 50% = 0.6 kWh). Add these numbers up to get an average impact:

- Ah, but wait! Some of you turn off your monitors at night. Some of you already have your computer set up to standby, hibernate, or sleep. So we’re putting in a “fudge factor” and reducing the kilowatt-hour savings by 20%:

- Still with us? Finally, we know that a fossil fuel burning power plant releases an average 1.55 pounds of CO2 for every kilowatt-hour it creates:

- Based on our assumptions, turning off your computer system at night for a month will result in an average carbon dioxide savings of 51.3 pounds, which we will credit at 1.7 lbs per day.
- Accepting this challenge will also save you about $3.30 in electricity costs.
You get the idea. A sleeping computer is good, but an unplugged computer is even better. And the longer you can keep that computer powered off, the more electricity you save and the less carbon dioxide you’re responsible for creating. And don’t worry. When you turn the computer back on tomorrow, Carbon Rally will still be here. Go to sleep, Rallyers!
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