Greening our computer systems

Well, I've done a little research and found out that the desktop computer system with which I am currently typing to you was using up a lot of electricity that it does not have to use.

The biggest culprits were:

• Leaving it on when we're not using it
• The monitor
• The printer

Leaving it on when we're not using it

By far, the biggest usage of energy stems from leaving the system on when we are not using it. We usually leave the system on because we frequently access it at random times during the day, and booting our Windows machine from scratch just takes too darn long when all you want to do is a quick check to see if you have any new emails or check the weather. (Booting, logging in, and waiting for the network to get an IP address over a minute on our computer!)

But one thing I hadn't tried before is standby mode. I thought of that only in the context of laptops where you are trying to save battery life, but I was surprised to learn it works on desktops too. Not only that, it works well!

My Dell Dimension 4550 (yeah, I know, it's old, but it still works fine for checking the emails) goes into standby mode in approximately 3 or 4 seconds. When I touch any key on the keyboard, it wakes up again and reconnects to the network in about 5 or 6 seconds. That's fast enough for me, and certainly much faster than the 90 or so seconds it takes to boot from scratch.

But how much does it save? Well, a running computer that is not doing anything will use about 60 to 150 watts depending on the beefiness of the configuration you have. A full-on latest-and-greatest gaming machine will be on the 150 watts end of the spectrum, and your basic email checking system like I have will be closer to the 60 watt end of the spectrum. Either way, if you put your system in standby mode, the usage drops to range of 1 to 5 watts or so.

Let's say we use our desktop 3 hours a day (yes, I am a nerd!). The other 21 hours a day, it is idle. Also, let me figure that the difference between running the computer with the screen saver and standby mode is approximately 80 watts (= 0.08 kilowatts). Also, the marginal rate for our electricity is $0.22 per kilowatt hour because we are "over 200% of our baseline." I don't know where PG&E gets that baseline from, but it is pretty low if I have to scrimp and save in order to meet it. In any case, the point is that any kilowatt-hour we save will save us $0.22

Let's calculate that for a year:

21 idle hours * 365 days a year = 7665 idle hours per year
7665 idle hours * 0.08 kilowatts = 613.2 kilowatt-hours
613.2 kilowatt-hours * $0.22 per kilowatt-hour = $134.90 a year

That means we are saving $135 a year without spending a dime to do it! Not bad, eh?

Even better, in the Windows Power Options settings, you can set your computer to go into standby mode automatically if there is no user activity for a period of time. I have ours set to 1/2 hour in case we forget to put it in standby mode manually.

The Monitor

We had 2 CRT monitors from back in the dark ages. (ie. the 1990s). One was a 19" Komodo monster, and the other a small 15" one that I used for my Linux machine whenever I run that. The 19" monitor was physically HUGE, but had a gorgeous display that could do 1600x1200. It consumed about 80 watts while it was on, and about 1.5 watts in sleep mode.

My wife's company was moving and did not need some of their Sony LCD monitors any more, so we acquired two of them for very cheap to replace our CRTs. Instead of throwing out the CRTs, we placed them on Craig's List, and they were taken pretty quickly. Getting used monitors and selling used monitors -- reusing older equipment is better than recycling! No landfills got any bigger as a result of our transactions.

In any case, I calculated that the new LCD monitor uses about 35 watts when it is in use, and about 0.6 watts in sleep mode. That means it saves about 45 watts in regular use, and 0.9 watts in sleep mode.

Let's calculate:

Regular usage

3 hours a day of usage * 365 days a year = 1095 hours a year
45 watts saved in regular mode * 1095 hours a year = 49.275 kilowatt-hours
49.275 kilowatt-hours * $0.22 per kilowatt-hour = $10.84 a year

Sleep mode

21 idle hours * 365 days a year = 7665 idle hours per year
7665 idle hours * 0.9 watts = 6.9 kilowatt-hours
6.9 kilowatt-hours * $0.22 per kilowatt-hour = $1.52 a year

That means the monitors will save us a total of $12.36 a year each, which means they will pay for themselves in terms of electricity alone pretty quickly. (Plus we sold the CRTs for a little money, so that offset of the costs too.)

The Printer

We don't print things very often, but the printer stayed on all the time in case we did. Our HP color inkjet printer would use 12 watts while printing, 5 watts when it was idle but in ready mode, and surprisingly, about 4 watts when the thing was turned completely off! The usage of energy when it is turned off is what is referred to as "vampire energy". I'll talk about that in a subsequent blog post, as many devices in your home like TVs, DVD players, cell phone chargers, etc. use this vampire energy and there are ways to combat that as well.

We probably printed on average for about 3 minutes a day, which is 0.05 hours of usage a day and 23.95 hours of idle time a day.

To solve this problem, I got a spare power strip and plugged a few of the non-essential things like the printer into it. When the power strip, you can flip the power button on the whole strip and any devices plugged into it will use no electricity at all. Plus, the power strip has the advantage of giving surge protection. No when we want to print, we flip the switch on the power strip, hit the power button on the printer, and we're ready to go in about 15 seconds.

Let's calculate:

23.95 idle hours per day * 365 days a year = 8741.75 idle hours per year
8741.75 idle hours * 5 watts idle mode = 43.71 kilowatt-hours
43.71 kilowatt-hours * $0.22 per kilowatt-hour = $9.62 a year

Total

With a few simple changes and a few smart transactions, we will save:

$134.90 putting the computer in standby mode
$12.36 switching to LCD monitors
$9.62 putting the printer on a power strip and turning it off
-------
$156.88

Not too shabby!

Ooo, I almost forgot. The total kilowatt-hours we will save is:

613.2
49.275
6.9
43.71
------
713.085

If each kilowatt-hour is generated from a fossil fuel like coal or natural gas and represents 2.095 pounds of CO2, that means our savings represent a total of 1494 pounds of CO2 not released into the atmosphere. That's where the real savings are!