Saturday, September 5, 2009

Wake On LAN (WoL) – Saving the World 1kW At A Time

When i was running Windows Vista i never even considered setting my computer to go to sleep for a number of reasons:

  • Vista’s recovery time was too long
  • I use my computer as a server for a number of services, which i frequently use remotely
  • My son likes to use the PC as a media box

Now that i have Windows 7 installed, i have taken to using the sleep feature since it wakes up in a matter of seconds.  By default Windows 7 uses the Balanced power profile which puts the computer to sleep after 30 minutes when running on power.  This caused me to think about how much power my computer had been using over the past few years.  In Perth, the cost of power is currently 12.67c/unit so we can use the following formula to calculate the amount of power a device is using:

Cost ($) per day = (wattage) / 1000 x ($$/kWh) x (hours used per day)

The power supply in my computer is 500W.  Until i get a cheap energy power meter that can accurately measure the utilisation accuracy, lets assume an average 300W usage (based on the components in my computer).  Plugging this into the above equation means that my computer is costing $1.06 a day to run!!  I really should have done this calculation a few years ago.  Its pretty easy to see that any down time on the computer is going to save some serious $$ over the year.  This is why I’ve started to use WoL as described in my previous post.

I recommend following this guide on Lifehacker to setup WoL on your network. I’ll be writing in the near future on some issues i found with using WoL, in particular the miriad of utilities out there that don’t work, why they don’t work and present a little utility i wrote for my own use while on the train the other day.

This means that for the majority of the day the PC is not running and consuming power, but is available whenever i need to use it.  Since the price of power is only going to rise in the near future, this is going to save me more and more money.  As humans with a growing energy problem, we should all be looking at solutions like this to save power when its not required.  Gone are the days when we can just be lazy and not think about it.

No comments: