MidAmerican Energy’s wind farm in Adair, Iowa. Facebook is working with MidAmerican to build a similar wind farm near Wellsburg, Iowa, where it will help power Facebook’s planned data center. Courtesy of MidAmerican Energy

Thanks to National Public Radio (USA) for this story about sourcing power for the special needs of modern technology:

You hear the term “the cloud” or “cloud computing,” and you picture something puffy, white, clean and quiet. Cloud computing is anything but.

Even from a distance you can hear the hum of a modern data center. Last week, I visited one of the largest in Santa Clara, Calif., in the heart of Silicon Valley. It’s called SC1, is owned by DuPont Fabros Technology and is about a quarter-mile long.

“It’s about the same size and length as a Nimitz aircraft carrier,” says Paul Hopkins, a regional vice president for the company, shortly after buzzing me through the door.

The entrance is guarded, and employees need fingerprint scans to get in and out. Hopkins has agreed to show me around.

Paul Hopkins, a regional vice president of DuPont Fabros, stands in the chilling plant of the company’s newest Silicon Valley data center, dubbed SC1. Steve Henn/NPR

SC1 isn’t fully built out yet. But when it is, it will use enough electricity to power more than 57,000 homes. Just inside the door, there is a corridor that stretches in a straight line for more than 1,000 feet.

“The guys that work here, a lot have their own little Razor scooters to get around,” Hopkins says. “It’s a heck of a long walk if you’re walking back and forth all day.”

DuPont Fabros is one of a half-dozen cloud storage providers you’ve probably never heard of. But their business is to build out these enormous buildings that house and cool millions of computer servers. This company’s customers include Microsoft and Facebook.

And this building is massive. Picture dozens of cavernous ballrooms lined up in a row. Now elevate the floors, run superpowered air condition systems underneath, and then stuff the space with as many racks of computers as you can possibly imagine.

“In one of these rooms here, we could fit 450 cabinets. Each cabinet has 30 to 50 servers — just a ton” of computing power, Hopkins says.

All those machines running full out use a huge amount of energy and throw off a lot of heat.

SC1 has a half-million-gallon chilled water tank to cool off the machines if the regular air-conditioning system fails. The tank looks like a small office building, easily six or seven stories tall. But when the servers are running at capacity, they produce enough heat to evaporate all of that water in just 30 minutes.

Researchers at Greenpeace estimate that if the cloud were a country it would be one of the biggest consumers of electricity on the planet.

“It would rank around sixth in the world,” says Gary Cook at Greenpeace. “That is right after Russia and right before Germany.”

Other estimates are smaller, but the figures are still staggering. The New York Times estimated that cloud computing consumed 30 billion watts of power a year in 2012. That is as much power as produced by 30 nuclear power plants.

And the cloud is growing fast. So to control electric costs, big cloud computing companies are traveling to the ends of the earth…