Should I Turn Off My Computer At Night To Save Energy?

April 18, 2010

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Sure, go ahead.  You will definitely save a little energy.  The key word is that sentence is “little”.

First of all, computers aren’t the energy hogs that many people think they are.  The laptop I use at work has a 90 watt AC adapter, and the Mac Mini I have at home has a 100 watt AC adapter.  It’s important to note that these are maximum wattages.  Most computer usage doesn’t come anywhere close to the max, and when it does, it’s for short bursts.

Electricity usage is measured as a kilowatt hour (kWh).  The means that a device that has constant usage of 1000 watts would use 1 kWh every 60 minutes.  The cost per kWh varies, but is generally in the ballpark of 10 cents.  This means my Mac Mini costs about 1 cent per hour to operate when it is at its maximum consumption rate (100 watts = 1/10 kW).

But that’s not even what we’re talking about. I wouldn’t save the entire 0.1 kWh by powering off the computer.  Like most users, I’m going to put my computer into sleep mode at night.  Sleep mode typically uses between 1 and 5 watts.  In the case of my Mac Mini, 1.39 watts.  I wasn’t able to find this information on my exact model of laptop, but I suspect that its usage is similarly low, especially in “hibernate” mode.

Is it worth the effort to shut down your computer to save a few watts per hour?  Let’s assume that your computer uses a relatively high 5 watts when in sleep mode.  Let’s also assume that it is idle 75% of the time.  That’s 126 idle hours per week, or 6552 hours per year.  Multiply this by a usage of 5 watt per hour, and you get a savings of 32,670 watt hours, or 33 kilowatt hours.  Congratulations – you just saved $3.30.  Have a Mac Mini like mine, and the savings is just $1.25 per year.

This makes even less financial sense for businesses, which are paying their employees to shut down the computer at night and restart them in the morning.  If we assume 1 minute of lost productivity per day for 250 work days, this is more than 4 hours of lost productivity!  Unless you’re paying your employees less than 90 cents per hour, you lost money on this exchange (assuming the $3.30 in energy savings).

Of course, you could argue that every little bit of saved energy adds up, in terms of environmental impact.  This is definitely true – and if you want to conserve every little bit of energy, then go ahead and shut down the computer.  However, there are a lot of other changes that give you a lot more bang for the buck.  If you have a 60 watt incandescent bulb in a lamp you use an average of two hours per day and switch it out with an equivalent compact fluorescent bulb (using 13 watts), you save 47 watts per hour of use – or 34 kWh during the course of a year ((34 X 2 X 365)/1000).  Yep, taking a minute to switch out a bulb saves as much energy as shutting down and restarting your computer 365 times!

I’m not suggesting that we waste energy.  I’m not even suggesting that we shouldn’t power off computers and other unused electronics.  I’m simply suggesting that if you’re willing to put the effort into this very small energy savings, you might also focus some energy on things that save even more energy.

Save the Wolves

September 10, 2009

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Over the course of a century, American society will have publicly (and privately) bountied, extirpated, protected, reintroduced, and then hunted one of the great mammals of the world. The Gray Wolf was once the most widespread mammal species in the world, covering enormous portions of all three continents encompassing the northern hemisphere. In North America, the wolf struggles to regain a foothold in portions of its historical range, and in the United States there is an ongoing legal battle over the status of the gray wolf going forward.

While the wolf population is stable and relatively healthy in Alaska and various eastern states (Michigan, Wisconsin, etc), the wolf’s future is decidedly unknown across the Rocky Mountain west. In Idaho and Wyoming, the wolves are considered experimental and nonessential, and can therefore be killed by private citizens without legal ramifications. In 2008, the federal government attempted to relax the protections for the wolf populations, as the government had decided that the populations, as a whole, had recovered to the point that a blanketed national protective law was no longer necessary. Various environmental groups filed for an injunction in federal court and have proceeded with a lawsuit to re-instate full federal protection for the species.

The biggest point, which is often overlooked, is that the wolf is not a solitary, singular animal in the vein of bears, big cats, and most other predatory mammals. Gray wolves live and die as a team of hunters, with a specific and legendary social hierarchy. If the balance of this hierarchy is altered, the pack itself can falter. Killing a single, seemingly lone wolf can destroy a pack of up to 20 animals. Biologically, the wolves have shown again and again that they are the “personal trainer” of the ecological world they exist in. After wolves were re-introduced to Yellowstone National Park, the elk, bison, and deer populations became healthier, leaner, and less diseased. The same effects have been seen throughout the west. Losing the efficient predatory machine of the wolf pack because of the intentional killing of 1-2 animals will prove a tragic effect over the course of time.

Unfortunately, politics always plays a role in ecological issues of the modern day, and the gray wolf has certainly not escaped this reality. The state governments of the Rocky Mountain region have come down consistently on the side of the private citizens, including the ranchers and other livestock owners. The wolves have been deemed a threat to the safety and profitability of a large industry. These industries do have legitimate concerns as packs of roving predators cross their ranch lands, but there is a balance to the financial impact versus the biological necessity of top predators.

In time, it is hoped that all facets of society could understand and appreciate the importance of a healthier ecosystem. The gray wolf is a top predator who not only keeps prey populations in check, but also makes the forests, grasslands, and alpine regions healthier. The human intervention on behalf of the wolves is certainly not over, but it must said that future decisions must be made based on sound science instead of political whims from government officials at the local, state, and federal levels. All of us will be impacted by decisions like these as our ecological world continues to degrade from society’s encroachment, both intentional and unintentional. We all need to educate ourselves, make educated opinions, and openly support whichever side with which we find agreement.