Debate over data center green claims

How green is Apple's iCloud data storage service?  That question provoked debate this week, as environmental activism group Greenpeace released a report critical of Apple's choices of power supply for its data center in Maiden, North Carolina, where the iCloud storage is based.

Greenpeace's report, How Clean is Your Cloud (52-page PDF), notes the explosive growth of cloud-based data and computing services offered by companies like Apple, Facebook, Amazon, Microsoft, Google,
and Yahoo.  These services are made possible by data centers, centralized networks of servers and computer infrastructure.  As Greenpeace put it, "Data centers are the factories of the 21st century information age, containing thousands of computers that store and manage our rapidly growing collection of data for consumption at a moment’s notice."

Data centers can be major consumers of electricity, needing cooling and air handling as well as energy for raw processing operations.  Some data center operators seek out renewable electricity, while others are developing on-site generation.  Most work to improve their energy efficiency, making the best possible use of the energy they need.

Apple has touted the green credentials of its Maiden data center, which was designed to earn LEED Platinum certification from the U.S. Green Building Council.  Apple's Maiden facility will also include a 20 MW solar facility on land adjacent to the data center, as well as a 5 MW biogas-based fuel cell system, systems Apple describes as "the nation’s largest end user-owned solar array" and "the largest nonutility fuel cell installation in the United States."

Greenpeace's report notes that despite these investments, Apple's data center is located in an area where utilities source a significant amount of power from coal-fired power plants.  Greenpeace and Apple dispute how much power the Maiden plant will consume (differing by as much as a factor of 5), and thus what fraction of its electricity will be produced from renewable on-site generation.

Whatever the facts may be, the debate illustrates society's interest in the environmental impacts of our technological choices - as well as the difficulty in evaluating some claims of greenness.