By John W. Verity

Green IT is clearly an idea whose time has come. With rising energy costs and growing concern over climate change, who wouldn't want to make IT more Earth-friendly? Less clear, however, is whether the economics of green IT can work for CIOs. That's especially true for the CIOs in businesses that must balance demand for greater social responsibility with the need to show growing sales and profits.

Similarly, which changes in IT gear or data center design, for instance, provide the biggest environmental ROI in the shortest period of time? How should a company go about crafting a green IT strategy? "It sounds simple, but there's still a big gap between strategy and implementation," says Miles Kelly, VP of strategy at 365 Main Inc., a San Francisco-based data center developer and operator.

Clearly, few enterprises can even contemplate, much less build, the kind of sea-anchored, wind-powered data centers that Google, a self-proclaimed leader in the green IT movement, has publicly envisioned. Yet no CIO or IT executive can escape or ignore the growing calls for "greener" IT. Even as the use of IT brings new energy efficiencies to the economy as a whole, as the U.S. Environmental Protection Agency (EPA) declared in 2007, rapid growth in the number and the size of data centers is significantly affecting the nation's power grid and climate.