Keller was called in to apply their drilled shaft expertise to 96 miles of Competitive Renewable Energy Zones (CREZ) transmission line through west Texas.

345kV CREZ Transmission Line
Inserting the drilled shaft cage into the hole.

The project

First introduced to Texas in 2005, the Competitive Renewable Energy Zones (CREZ) are designated areas where renewable energy technologies integrate with traditional energy sources. Oncor completed approximately 1,000 miles of new transmission lines to support this new CREZ in west Texas. Keller was called in to apply their expertise to 96 miles of the CREZ transmission line.

The challenge

The soil conditions were poor in some areas including slurry and hard rock. Drilling needed to be performed near areas of high voltage with electric distribution lines as an overhead concern.

The solution

Over 500 structures were required which included large diameter anchor bolt foundations and lattice structures consisting of stub angle foundations for towers. The drilled shaft foundations ranged in diameter from 6.5 ft to 13 ft at depths of up to 45 ft deep. The scope of work included rock drilling, installation of reinforcing steel, and furnishing/placing concrete.

Project facts


Oncor Electric Deliver Company, LLC

Keller business unit(s)


Main contractor(s)

Chapman Construction