Search engine giant Google Inc. plans to invest $600 million to expand its massive data center outside Charleston, according to records filed with Berkeley County.

The facility, which sits half an hour north of Charleston, is one of only a handful of data centers the technology giant runs in the U.S. It’s part of the backbone that keeps services like Gmail and Google Drive online.

Since it first opened, Google has pumped $1.8 billion into the decade-old site, which is in Moncks Corner, but details of its expansion plans are still limited. The company declined to describe its plans until they win the blessing of Berkeley County officials.

Outlines of the plans were disclosed by Berkeley County Council, which will consider a property tax deal for the expansion. Under the terms of that arrangement, Google will have until the early 2030s to finish the new development.

The county would formally ink the deal with a Google entity called Maguro Enterprises, which was initially established to hide the company’s identity while it was making plans for the data center in 2006.

The latest expansion has been discussed by council previously under the code name "Project Linden."

"Google is proud to call Berkeley County home to our data center, and we look forward to future opportunities to invest in this great community,” Lilyn Hester, the company's Southeast public policy head, said in a statement.

The company runs eight data centers in the U.S. and 15 worldwide, including three in the Carolinas and Georgia. Google didn’t say what prompted the expansion plans.

The company’s growth in South Carolina has drawn criticism from environmental groups, who say that the data center is drawing too much water to cool its servers. The company sparked controversy locally when it asked for permission to pull 1.5 million gallons of water a day from beneath Berkeley County, a request that has since stalled.

Reach Thad Moore at 843-937-5703. Follow him on Twitter @thadmoore.