Are there any "green" advantages (like power or cooling) to using VoIP versus a traditional PBX?

Everyone is trying to be green in the business world, but VoIP only offers limited advantages over a traditional PBX. In either case, voice consumes little in the way of resources, whether it be power or bandwidth. VoIP would be more efficient in the sense that a converged network that handles both voice and data is less resource-intensive than having separate networks for each, which is the norm with legacy telephony. However, when it comes to green IT, the real culprits are servers and the surrounding infrastructure to support data services. VoIP really has minimal impact on these requirements, and switching away from a PBX will not make an appreciable difference.

The story becomes slightly stronger if you think of VoIP in the broader context of IP communications. Telepresence...

and videoconferencing are the best examples of this, where the voice component is basically a VoIP call. In these cases, the green angle has become a key selling point in the sense that these solutions reduce the need for travel. Less travel means less flying on airplanes, which translates into reduced carbon emissions and usage of fossil fuels. These benefits have more to do with the environment than IT, but by association can be positioned as one the virtues of VoIP.