Chicago Business News reports that Microsoft plans to open another massive data center, in Northlake near Chicago in 2009 that will be central to the software giant’s war with Google Inc. for Internet supremacy.

The Data Center, large enough to hold eight football fields, is mooted to cost more than $500 million to build, sources familiar with the plan say.

Microsoft continues building it’s Internet infrastructure around the country to better compete with Google’s and Yahoo Inc.’s search engines and to provide more Web-based services. The data center would be Microsoft’s third nationwide since its push began in earnest last year.

“We’ve had smaller data centers, but this is the first time we’ve had a major player jump in here,” says Jim Kerrigan, a principal with real estate brokerage firm Staubach Co. who specializes in data centers but isn’t involved with the Microsoft project.

“Historically, Chicago has been a planes, trains and automobiles town. This shows we’re still benefiting from our centrality.”

The data center will house thousands of computer servers that process Internet activity and other network services. Despite its size, the center probably will employ no more than 75 people to operate the servers.

Construction began in September at the site located next to two sprawling grocery warehouses on a narrow frontage road along Interstate 294. While the surroundings may seem odd for the world’s largest software company, the location provides two key things that data centers need: a large amount of electrical power from nearby transmission lines and access to fiber-optic lines.

It’s unclear whether Microsoft plans to lease or own the building. Two St. Louis companies, Ascent Corp. and Koman Group, are developers on the project. The firms decline to comment on Microsoft’s plans.

“It’s a confidential project; we’ve been told not to say anything,” says a spokeswoman for Turner Construction Co., which is listed as project manager on documents filed with the city of Northlake.

New York-based Turner was hired for the two other recent Microsoft data centers: a roughly 500,000-square-foot facility in Quincy, Wash., that opened in April and another under construction in San Antonio. The company has said it is working on other undisclosed U.S. and international sites for Microsoft.

Such secrecy is common in the industry. The facilities themselves bear no signage and are built to be nondescript and easily overlooked, in part as a security measure.

“They keep it low-profile,” says Tim Snead, city administrator in Quincy. “There’s nothing to look at. They’re just big concrete buildings.”

The Northlake facility is to open by the middle of 2009, the people familiar with the plan say, on a fast-track construction schedule that will have more than 500 workers on the job at peak times.

While the number of permanent jobs at the data centers is relatively small, Mr. Snead says, Microsoft’s facility has attracted other centers as well as ancillary businesses that provide electrical service and maintenance to the generators and massive cooling systems.