Compared to familiar climate-saving programs that aim to stuff greenhouse gases into the ground or harness the power of the wind, ideas like "cloud computing" are hard to penetrate. Still, the practice is gaining attention as the information technology (IT) industry promotes it as a tool to save both energy and money.

Meanwhile, though, companies, environmentalists and consumers find themselves struggling with a new question: How do you measure the carbon footprint of a "cloud"?

First there is the murky business of understanding exactly what cloud computing is. IT professionals use the term broadly to describe data processing operations that are outsourced to server farms, instead of being powered on-site (in the server room of an office, for example). For businesses, this could include websites or networks that are hosted remotely. For individuals, it could be Google documents, digital storage space and so forth.

There is no question that computing needs are expanding at a rapid clip. Data centers -- which can be as big as two or three Walmart stores -- have become nerve centers of the digital age. First promoted as a pragmatic way for businesses to avoid IT maintenance hassles, they've now been adopted as a cause for energy efficiency advocates who want to rein in the escalating growth of IT power demands.

The claims are numerous. Cloud computing lowers energy costs for users and cuts greenhouse gas emissions by streamlining information-crunching into single facilities on speedy machines, proponents say. With efficiency upgrades to the centers themselves on the rise, less and less energy is needed to power the digital world.

A July report commissioned by the nonprofit Carbon Disclosure Project, which tracks corporate climate change information, outlines more specifics: Cloud computing, it says, is projected to help large U.S. companies save $12.3 billion on energy costs and cut out 85.7 million metric tons of carbon dioxide emissions annually by 2020.

The forecast, conducted by independent analyst firm Verdantix, considers likely IT trends among the 2,600 or so American companies generating more than $1 billion a year in revenue. It also analyzes electricity consumption data, adjusted to account for the varying carbon intensity of energy sources throughout the country.

Bigger energy bills loom for do-it-yourselfers

The savings result from the data center operators' interest in letting no bit of power capacity go to waste. Scattered servers are energy guzzlers, the report says. Much of the power needed is for heating and cooling of space and machines. Maintaining HVAC controls for spread-out sets of servers is more energy-intensive than managing a central facility.

On-site servers also must be equipped for peak data usage -- heavy hits on a retail website during a new product launch, for example. The rest of the time on that site, Web traffic plateaus and the built-in capacity of the servers goes to waste. Open data centers, on the other hand, can redistribute that excess capacity to other clients, using already highly efficient servers.

The IT industry has been trying to generate some buzz. Last month, Hewlett-Packard Co. released its design of a modular data center that it called the "world's most efficient." Google Inc. has made the same claim of its centers over the years. And in April, Facebook launched the Open Compute Project, a collaborative effort to build one even better.

The flurry of action comes after years of unchecked and unorganized growth, said Paul Dickinson, executive chairman of the Carbon Disclosure Project. A 2007 Energy Star report from U.S. EPA listed increased digital communication, record-keeping and financial transactions as forces pushing up the demand for data processing and storage. Greenpeace estimated that cloud computing worldwide demanded 662 billion kilowatt-hours of electricity in 2007, more power than consumed by the entire country of India, or of Germany.

The U.S. government itself more than quadrupled the number of data centers it operated between 1998 and 2010, growing from 432 facilities to more than 2,000. Now, it is trying to scale back the sprawl by cutting and consolidating duplicative centers.

"The proliferation of infrastructure has created an environment that enables redundant systems and applications to sprout like weeds," said federal Chief Information Officer Vivek Kundra in a blog post last month.

By the end of 2011, 178 federal data centers will close, with a total of 800 planned to shutter by 2015 (Greenwire, July 20).

Facility closures and tech efficiency (along with the global economic slump) have already contributed to a deceleration in the growth of electricity consumption in data centers since 2005, according to another study, this one released by Stanford University professor Jonathan Koomey in early August.

Steps toward consolidation and efficiency are a no-brainer for the government and other operators who want to cut their energy costs, say advocates. A better facility means reduced energy use, which means lower bills.

Consolidation's better, but what's the energy source?

"It's not magic; it's mathematics," said Radu Gheorghievici-Pohl, an executive at IT efficiency firm 1E. With energy costs fluctuating, he says, companies must address what's in their control.

"You have to deal with energy in a more conscious way," he said. "Nobody knows how prices will be developing in the next period."

To that end, server machines are becoming less wasteful; data center designers are making optimal use of physical space; and HVAC innovation is achieving the same temperature and ventilation controls with less energy. These gains are measured by power usage effectiveness (PUE), adopted by industry group the Green Grid as a standard metric to compare power needed to run the server equipment with total power needed in the data center.

A recent Greenpeace report, however, says this calculus is overlooking a major variable: the energy source. Companies are relying on healthy PUE ratings, the report says, to "communicate externally that their data centers are 'green' and sustainable without accounting for the full environmental picture."

Though internal efficiency is a worthy cause, the April report says, energy savings are superficial if the data center is powered with a non-renewable source.

That is often the case. Take North Carolina, for example: The western part of the state is becoming a data center hub, with Apple, Facebook and Google all setting up shop there. The geography is inviting; risk of natural disasters is low, telecommunications infrastructure is already in place and energy is dirt-cheap. The state's major utility is Duke Energy Corp., which generates more than 60 percent of its power from coal, with nuclear making up most of the rest. A pending merger with Progress Energy Inc. is expected to even out that ratio.

Similarly, Facebook's announcement of a new data center in Prineville, Ore., was met with criticism from environmentalists. They say the 150,000-square-foot building (which is planned to double in size) should have been located in an area powered by clean energy. Instead, it will be powered by PacifiCorp., which depends mostly on coal and natural gas for generation. Renewables make up 10 percent of its energy portfolio.

Facebook defends the site, which opened in April, pointing to its robust efforts to minimize the center's effects on the environment. South-central Oregon's low-humidity climate allows the building to draw in outside air, process it through layered filters and use it to cool the space and machines. Other energy-saving measures are in place, including rainwater reclamation and reuse of server heat to regulate office temperature. Facebook says the Prineville site uses 38 percent less energy to do the same work as the company's existing facilities.

As part of the Open Compute Project, the data center's custom server and building designs have been made public for others in the industry to use and expand upon.

"The new computing capacity will enable us to offer great new social experiences, while setting new standards for environmental responsibility in data center design and operations," said Tom Furlong, director of technical operations at Facebook, in a press release.

'How dirty is your data?'

These kinds of efficiency efforts are the most accessible levers companies have to control environmental impact from IT operations, said Verdantix's Stuart Neumann, who worked on the Carbon Disclosure Project report. Though aiming to build in renewable-heavy areas would be environmentally beneficial, it could also result in higher energy costs for companies.

"Clearly if you can coordinate with locating data centers in an area with a focus on renewable energy, that's a good thing," he said. "But you ... need to consider cost-effective service."

Greenpeace counters that many corporations have the resources to scope out more sustainable ground.

"It is imperative that IT companies use their market power to make clean and reliable supply more available in addition to their advances in computing efficiency," says the organization's report "How Dirty Is Your Data?" "IT can help drive clean energy supply across the regions in which it operates."

Companies don't have to sacrifice cost-effectiveness to factor energy sources into data center siting, said Gary Cook, an author of the report.

A few of the leading U.S. tech companies have already made hefty investments in clean-sourced data centers. Yahoo has an operation in Washington state that draws from a power supply with renewables making up an estimated 88.5 percent of the mix. A new data center in Boardman, Ore., is expected to tap into a similar spread of clean energy.

All-renewable facilities are slowly sprouting up, too. Early-phase outfits in Iceland, Green Earth Data and GreenQloud, for example, both claim to offer 100 percent renewable energy, powered by the country's abundant geothermal and hydropower sources. These types of data centers may yet take hold widely, but for now remain sparse.

If business sense necessitates that a company opt for a fossil fuel-powered site, Cook says it should work with local government and utilities to add renewable power to the grid.

"They're right to look at [energy source] as a real cost," he said. "Our ask of the company is to be factoring in access to clean energy now and into the future."

As computing demand continues to swell worldwide, tech companies are well-positioned to cast the direction of development, he added.

"These are the innovators of the economy," he said. "Their footprint is only going to get bigger and bigger. Growth is not a bad thing; it's important for driving lower-carbon activity. It can be a springboard to building a green economy."

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC., 202-628-6500