Google has been at the forefront of energy efficiency quite some time. Read on to learn more about Google current initiatives.
They also have lots of data and metrics to compare their energy use per Google search to other activities.
" ... Data centers ... account for most of Google’s energy needs ... take our energy use seriously and, from the very beginning, Google has focused on designing systems that use as little energy as possible ... operating what we believe to be the world's most efficient data centers."
" ... Google-designed data centers use about half the energy of a typical data center ... energy used per Google search is very small ... currently use about 1kJ (0.0003 kWh) of energy to answer the average query ... roughly .2g of CO2 ... often take the place of more carbon- and time-intensive activities, such as driving a car to a library or spending hours navigating shopping malls."
" ... commitment to sustainability goes beyond just electricity and carbon ... two Google facilities currently run on 100% recycled water, and by 2010 we expect recycled water to provide 80% of our total data center water consumption ... share our own data center best practices and are encouraging our industry peers to do the same ..."
" ... if all data centers operated at the same efficiency as ours, the U.S. alone would save enough electricity to power every household within the city limits of Atlanta, Los Angeles, Chicago, and Washington, D.C."
Via: Google LINK