Upgrading older hardware with energy-efficient components is an arguably green business choice: By extending the life of your machines rather than trading them in for brand-new ones, you reduce the world's e-waste pile -- while saving yourself some cash. Digital Realty Trust, which owns, acquires, and manages technology-related real estate worldwide, took that philosophy a step further; the company transformed part of a 90-year-old printing plant in Chicago into the world's first LEED (Leadership in Energy and Environmental Design) Gold-certified datacenter facility.

[ Discover the techniques used by other 2008 Green 15 winners to make their IT more sustainable. ]

"This project shatters the myth that LEED certification can only be achieved within newer facilities," says Jim Smith, vice president of engineering at Digital Realty.

LEED is a nationally accepted benchmark for the design, construction, and operation of high-performance green buildings. Developed by the U.S. Green Building Council, the rating system promotes a whole-building approach to sustainability by recognizing performance in key areas, including sustainable site development, water savings, energy efficiency, materials selection, and indoor environmental quality.

The project -- commissioned by an unnamed Fortune 500 client -- entailed transforming part of the R.R. Donnelly printing plant, built in 1917, into 20,000 square feet of raised-floor space with 4,000 kW of available IT load.

Measurements are key
Features of this project include sophisticated tools for measuring energy consumption: "These are not expensive, but they provide critical data that let you understand what is happening in the datacenter. Every datacenter should have this, particularly since it is such a small investment and provides such valuable information," Smith said. "Step one for energy-efficient operations is always to have a way to measure."

There are also tools outside the facility to monitor the air temperature. "The equipment makes sure the air is clean, and helps us improve performance of the ventilation system and improve indoor air quality," he said.

Digital Trust went with this particular location for a couple of reasons. First, the client simply liked the setting, right near the Loop. "Another important factor for us is that the LEED certification encourages reuse of existing structures, which is very energy-efficient when you look at how much energy is used in materials and construction for new buildings," Smith said.

Building to the green design
Striking LEED Gold also required advanced commissioning, a process to ensure that all of its systems are designed, installed, and tested to perform according to the design intent and the building owner's operational needs. "You learn a lot during this process and can apply that knowledge right upfront to make adjustments that ensure you are maximizing your energy savings," said Smith.

Undergoing the LEED process added 4 percent to the price of the overall project, according to Smith (he would not disclose the total cost) -- but in the end, it was worth the investment. "Very efficient from a cost perspective, and it has an overwhelmingly positive net present value. Definitely worth the cost," Smith said.