More and more organizations are coming around to the idea that Data centers present good opportunity to reduce energy cost. Data centers have more than 10 million computer servers which on average consumes 15 times more energy per sq foot.
Association To Save Energy has good set of policies and recommendations for migrating to energy efficient data centers -
Data centers and their energy usage are expected to grow:

The number of installed servers in the U.S. is expected to increase by 40 to 50 percent nationally in the next four years, with …