In order to reduce power consumption in my laptop, I've been using powertop, which is a nifty tool from Intel. If you've not used it already, you can install and run it using:
sudo apt-get install powertop
Powertop is a great tool to see which processes and causing the most wakeups on a so-called "idle" system. In most cases I see power being sucked away by unnecessary wakeups with Flash running in my web browser. Every little animated advert us causing wakeups, scale that up with multiple flash instances on a busy page and lots of tabs open on the browser and soon you see battery life being reduced.
So just how much power is being used? A couple of Watts per laptop? Scale this up across the globe and we soon see a massive carbon footprint caused Flash adverts and the like. And I'm just as hypocritical; this blog has Google ads embedded in it which are sucking your battery life away as you are reading this!
For netbooks that chug along on Atom processors at 1.3 to 1.6GHz this can be a significant chunk of CPU cycles consumed by Flash animation. So next time you wonder why your battery lasted only 2 hours instead of the promised 3 or 4 hours don't blame the OS - blame the glorious Web experience! :-)