Save energy, spare the air with efficient computer usage

Energy wasters: we’re talking appliances, electrical transmission lines, lighting systems and their main component parts (bulbs, lamps), whole buildings and more. And, in the “more” category are computers, of course.

I am fully aware that computers in idle or sleep mode consume electricity; but, what I do not know is how much electricity. Think that’s all there is to the computers-as-energy-wasters story? Think again.

Funny I should mention this because, relatedly, I found (using a computer, incidentally) this report: Monitoring Computer Power Modes Usage in a University Population,1 prepared for the California Energy Commission (CEC) by the California Plug Load Research Center at the University of California at Irvine.

According to the CEC in the report’s “Executive Summary,” of total state electricity consumption, computers account for around two percent. Not a lot, but not negligible either.

“New computers typically have built-in features such as sleep or hibernation that reduce energy consumption when the computer is not in active use. These features allow the computer to be switched to one or more low-power modes, or to transition into such a mode automatically. Study after study has made it clear that computer users are not employing these power-management options effectively, and that doing so could significantly reduce both residential and commercial electricity use. However, little research has addressed how, when, and why users engage – or do not engage – these options. A better understanding of user behavior is thus a crucial part of increasing energy efficiency for computers.”

I know in my own particular situation that if I’m only going to step away from my computer momentarily, no action is taken on my part to reduce the computer’s energy consumption. Should I be away from my computer for more than just a short time, well, the computer will automatically switch to a mode whereby energy being consumed is reduced. If there is more than five minutes of inactivity, the computer will automatically go into the sleep or hibernation mode. But, rarely is it that I purposely “sleep” my computer.

On the other hand, if I know that I won’t be using my computer for an extended period, I save what needs to be saved, close all programs and documents and then turn the device completely off.

There are times though that the computer is unplugged from the AC wall outlet, relying on back-up battery power. This is one of the best ways I can think of to allow the computer to be less of a drain on the electricity grid. There are times when computer usage following this procedure is more conducive to operating it in this manner.

For example, in my own home, electricity consumption is usually at its highest on weekday evenings from anywhere from 6 to 7 p.m. until about anywhere from 10 to 11 p.m. With the understanding that computer usage accounts for roughly two percent of all electricity consumption, by switching to battery operation during the times of biggest energy demand, then this can make a difference and provide for additional energy savings compared to drawing AC from the wall. Now imagine, if you will, the impact of an extremely large population of people using their computers doing exactly that: less demand would be placed on the electric grid.

As far as the referenced study above goes, perhaps the most profound finding of all, was that, overall, computer central processing units (CPUs) were “on” 61 percent of the day in what in the report is described as “User inactive” mode. Contrasted to this, the CPUs in the survey, overall, were “on” in the “User active” mode just seven percent of the time. These computers were office desktops.

Also from the report’s “Executive Summary”:

“This monitoring study highlights confusion about power management settings for office desktops. The situation may be better for home desktops and laptops: the 2013 survey results indicate that users have more control over their home desktops and laptops, and are less likely to give ‘don’t know’ responses when asked about them. However, since desktops use more power than laptops, and office desktops outnumber home desktops, any problem that affects office desktops has substantial implications for total energy efficiency.”

The takeaway: Smarter, more efficient computer operation can not only result in electric bills being lower, but air quality being better.


  1. Pixley, Joy E.; Stuart A. Ross. (University of California, Irvine). 2014. Monitoring Computer Power Modes Usage in a University Population. California Energy Commission. Publication number: CEC-500-2014-092.

– Alan Kandel