USENIX Association - Reducing Network Energy Consumption via Sleeping and Rate-Adaptation
Symposium paper focused on saving energy by taking advantage of network equipment idle time.

Alcatel-Lucent, GreenTouch - ICT Industry Combats Climate Change
The ICT industry players get it when it comes to developing energy efficient equipment as well as within their own operations. This white paper covers some interesting statistics for the ICT in general and networking equipment specifically.