A team at Microsoft Research has been working on measuring energy usage in IT, and has come up with a novel piece of software called Joulemeter. From the website
Joulemeter is a software based mechanism to measure the energy usage of virtual machines (VMs), servers, desktops, laptops, and even individual softwares running on a computer.
Joulemeter estimates the energy usage of a VM, computer, or software by measuring the hardware resources (CPU, disk, memory, screen etc) being used and converting the resource usage to actual power usage based on automatically learned realistic power models.
They’ll apparent be offering a download of the software. In the meantime you can read the abstract.




