One of the ways to save power in datacenters will be virtualization:
A couple of years ago, hardware utilization was driving the virtualization train. Now, however, hardware’s inexpensive compared with the cost of the juice to keep it running and the people to swap it in and out when it fails. So if oil stays near $70 a barrel, and refresh rates on datacenter gear stay in the sub five-year range, you can bet that datacenters will be completely virtualized and hyper-efficient in a couple years. Wish I could say the same for my car.