SANTA CLARA, Calif. -- Jeff Rothschild's machines at Facebook had a problem he knew he had to solve immediately. They were about to melt.
The company had been packing a 40-by-60-foot rental space here with racks of computer servers that were needed to store and process information from members' accounts. The electricity pouring into the computers was overheating Ethernet sockets and other crucial components.
Thinking fast, Mr. Rothschild, the company's engineering chief, took some employees on an expedition to buy every fan they could find -- "We cleaned out all of the Walgreens in the area," he said -- to blast cool air at the equipment and prevent the website from going down.
That was in early 2006, when Facebook had a quaint 10 million or so users and the one main server site. Today, the information generated by nearly 1 billion people requires outsize versions of these facilities, called data centers, with rows and rows of servers spread over hundreds of thousands of square feet, and all with industrial cooling systems.
They are a mere fraction of the tens of thousands of data centers that now exist to support the explosion of digital information. Stupendous amounts of data are set in motion each day as, with an innocuous click or tap, people download movies on iTunes, check credit card balances on Visa's website, send Yahoo email with files attached, buy products on Amazon, post on Twitter or read newspapers online.
A yearlong examination by The New York Times has revealed that this foundation of the information industry is sharply at odds with its image of sleek efficiency and environmental friendliness.
Most data centers, by design, consume vast amounts of energy in an incongruously wasteful manner, interviews and documents show. Online companies typically run their facilities at maximum capacity around the clock, whatever the demand. As a result, data centers can waste 90 percent or more of the electricity they pull off the grid, The Times found.
To guard against a power failure, they further rely on banks of generators that emit diesel exhaust. The pollution from data centers has increasingly been cited by the authorities for violating clean air regulations, documents show. In Silicon Valley, many data centers appear on the state government's Toxic Air Contaminant Inventory, a roster of the area's top stationary diesel polluters.
Worldwide, the digital warehouses use about 30 billion watts of electricity, roughly equivalent to the output of 30 nuclear power plants, according to estimates industry experts compiled for The Times. Data centers in the United States account for one-quarter to one-third of that load, the estimates show.
"It's staggering for most people, even people in the industry, to understand the numbers, the sheer size of these systems," said Peter Gross, who helped design hundreds of data centers. "A single data center can take more power than a medium-size town."
Energy efficiency varies widely from company to company. But at the request of The Times, the consulting firm McKinsey & Co. analyzed energy use by data centers and found that, on average, they were using only 6 percent to 12 percent of the electricity powering their servers to perform computations. The rest was essentially used to keep servers idling and ready in case of a surge in activity that could slow or crash their operations.
A server is a sort of bulked-up desktop computer, minus a screen and keyboard, that contains chips to process data. The study sampled some 20,000 servers in about 70 large data centers spanning the commercial gamut: drug companies, military contractors, banks, media companies and government agencies.
"This is an industry dirty secret, and no one wants to be the first to say mea culpa," said a senior industry executive who asked not to be identified to protect his company's reputation. "If we were a manufacturing industry, we'd be out of business straightaway."
These physical realities of data are far from the mythology of the Internet: where lives are lived in the "virtual" world and all memory is stored in "the cloud."
The inefficient use of power is largely driven by a symbiotic relationship between users who demand an instantaneous response to the click of a mouse and companies that put their business at risk if they fail to meet that expectation.
Even running electricity at full throttle has not been enough to satisfy the industry. In addition to generators, most large data centers contain huge, spinning flywheels or thousands of lead-acid batteries -- many similar to automobile batteries -- to power the computers in case of a grid failure as brief as a few hundredths of a second, an interruption that could crash the servers.
"It's a waste," said Dennis Symanski, a senior researcher at the Electric Power Research Institute, a nonprofit industry group. "It's too many insurance policies."
At least a dozen major data centers have been cited for violations of air quality regulations in Virginia and Illinois alone, according to state records. Amazon was cited with more than 24 violations over a three-year period in Northern Virginia, including running some of its generators without a basic environmental permit.
A few companies say they are using extensively re-engineered software and cooling systems to decrease wasted power. Among them are Facebook and Google, which also have redesigned their hardware. Still, according to recent disclosures, Google's data centers consume nearly 300 million watts and Facebook's about 60 million watts.
For security reasons, companies typically do not even reveal the locations of their data centers, which are housed in anonymous buildings and vigilantly protected. Companies also guard their technology for competitive reasons, said Michael Manos, a longtime industry executive.
To investigate the industry, The Times obtained thousands of pages of local, state and federal records, some through freedom of information laws, that are kept on industrial facilities that use large amounts of energy. Copies of permits for generators and data about their emissions were obtained from environmental agencies, which helped pinpoint some data center locations and details of their operations.
In addition to reviewing records from electrical utilities, The Times also visited data centers across the country and conducted hundreds of interviews with current and former employees and contractors.nation - interact