Clemson University’s $98 million wind turbine testing facility on the former Navy Base in North Charleston marked a milestone today as the machinery that will stress-test the world’s largest wind turbines began taking shape.

Picture an enormous gear-like ring about three stories tall. The “load application unit” installed today will be part of a testing rig capable of simulating extreme operating conditions on wind turbines capable of producing 15 megawatts of power — about five times what large land-based wind turbines produce.

To handle the weight and force of such testing, the turbines will be bolted to a concrete base 100 feet long and 15 feet deep. Installing that base was an all-night project completed earlier this year, involving 223 truckloads of concrete.

The idea behind the testing facility is that manufacturers from around the world will be able to pay Clemson’s Restoration Institute to test their gear under roof in North Charleston, before going to the great expense of putting the units in offshore wind farms.

The testing facility is being created using a $45 million U.S. Department of Energy grant, with a mix of additional public and private funds covering the rest of the project. Originally scheduled for completion in 2012, the facility is expected to be finished this year.

“It’s all starting to come together now,” said Project Manager Jim Tuten.

Read more in Wednesday’s editions of The Post and Courier.