Both Hewlett-Packard 's (nyse: HPQ - news - people ) Utility Data Center model and Sun Microsystems ' (nasdaq: SUNW - news - people ) N1 approach stress filling computers with the heaviest possible workloads--a change from the standard model of buying new servers when they run at 30% of capacity, for fear of hitting the occasional spike in activity.

FORBES: IBM Does The On-Demand Dance

High demand and aging delivery grids have forced some utility companies to restrict the amount of power delivered to a data center.

FORBES: The Growing Energy Demands Of Living Your Life In The Cloud

Google said Wednesday that it has signed a first-of-its-kind deal with an Oklahoma utility to buy 48 megawatts of wind energy to help power its data center in that state.

FORBES: Google Signs Utility Deal To Power Data Center With Wind Energy