The cost of electricity is a significant percentage of the overall operating cost of data centers.  Minimization of electrical consumption can significantly reduce data center operating cost via the proper planning of the physical infrastructure and  implementation of energy efficient technologies.  This can be realized by:

1. Properly designing the physical space to minimize “heat islands”
2. Locating heat generating devices such as air conditioners outside the primary data center and utilizing “Economizer” modes
3. Proper location of venting
4. Sizing the primary electrical systems and UPS to avoid operating above 75% of maximum load
5. Reduction of server count via virtualization and retirement
6. Migration to energy efficient computing platforms such as blade servers and multiprocessor/multicore solutions
7. Elimination of older, inefficient servers
8. Utilization of power management features (CPU throttling)
9. Storage centralization and the introduction of efficient disk storage (solid state drives, unused drive spindown)
10. Implementing and utilizing energy tracking systems to identify opportunities to reduce power consumption

APC offers a comprehensive white paper on this subject, which is available at : http://www.apcmedia.com/salestools/NRAN-6LXSHX_R0_EN.pdf