November 29, 2022
Blattner succeeds with installation of new turbine platform
The 302.4 MW Mills County wind project is located just north of Goldthwaite, Texas.
This project included a new turbine platform for Blattner to construct – 63 of the Nordex N149 4.8 MW turbines with a 108-meter hub height. With this larger turbine platform came a challenging foundation design. This construction consisted of a 62’ diameter radial rebar structure with 200 bolts at 14’ 3/8” in height yielding 603 cubic yards of concrete for the foundation base. Blattner’s scope of work also included 31 miles of subgrade, 79.5 miles of underground collection line and construction of the substation and O&M building.
The rocky, karst ground conditions proved challenging for the civil and collection teams. All 63 turbine sites had to be blasted prior to foundation excavations. There were also 23 sites that involved underground void assessment and pressure grouting. Void assessment consisted of drilling 4.5” diameter holes anywhere from 20 to 40’ depth below existing grade. Some sites were complete in a couple days, while other sites took nearly a month to complete due to the amount of grout being pumped into the underground voids.
The installation crews took many days of training and process improvement to learn the N149 platforms. This included a complex build of the nacelle and hub assembly. To date, the nacelle and hub assembly is the heaviest WTG lift by Blattner at 482,000 pounds.During the course of the project, the Mills County wind project team continued to grow in communication and coordination. Trades had to change sequence many times throughout the project and worked together so that each trade could be as efficient as possible. Across the board, the team experienced an exponential increase in productivity after the learning curves were met. Crews adapted to the new and challenging designs and platforms to build quality work, all while ensuring a safe work environment.
Completion Date: June 1, 2022
Location: Goldthwaite, Texas