After Washington state created a tax break for building data centers in rural areas, Microsoft is now expanding its data center in Quincy.

The company already has as 500,000-square-foot facility in the small Grant County town, where the hydropower is cheap and the broadband is plentiful. Data centers are buildings filled with servers that run on the Internet. For Microsoft, data centers run services such as its Bing search engine, Hotmail and cloud-computing platforms, including Azure and Microsoft Online Services. The company has built large facilities in Chicago, Dublin and San Antonio in the past year.

"The construction has already begun" on a new building in Quincy, said Lou Gellos, Microsoft spokesman. He did not know how long it would take to build.

Patrick Boss, a spokesman for the Port of Quincy, said Microsoft started building about 10 days ago. Microsoft had originally said it would build a 1.5 million-square-foot facility in three phases, but changes in data-center design may alter the original plan.

A new data center has to be at least 100,000 square feet to qualify for the tax exemption. Yahoo also has a data center in Quincy.

"We have had a lot of interest in the past two months [since the tax exemption was approved'," Boss said. "We’ve had a lot of companies who have come in with site selectors. My guess is this Microsoft site expansion will probably get people even more interested."

Microsoft declined to say how many jobs its data center had created. Boss estimated the data center employs 60 to 70 people, not including those who worked on building the facility.

"It’s a decent amount of jobs. For a place like Quincy that’s a good number of jobs. It’s a town of 5,000 or 6,000 people," he said. "The other side of this is the property taxes have been a gigantic help for Quincy. They haven't had to cut back on schools and educational spending."