The Lone Star State Builds a Greener Grid

Oncor and more than 1,000 contract crew members have been working for the past three years to deliver electricity from clean and renewable sources in West Texas to urban areas like Dallas, Houston and Austin as part of the state's Competitive Renewable Energy Zone (CREZ) project. Oncor's more than 1,000 miles of lines account for 25% of the total project aimed at increasing transmission line capacity on the Electric Reliability Council of Texas (ERCOT) grid.

Of Oncor's more than a dozen CREZ projects, which span 40 Texas counties, crews are constructing more than 800 miles of new lines, stations and reactive power compensation projects, and rebuilding about 200 miles of existing lines, including replacing steel towers and poles, adding conductors and circuits, and installing new conductors to improve the capacity of the lines.

Coordinating Crews

Oncor broke ground on the first CREZ project in the spring of 2009. Crews first focused on the default projects — existing lines that needed to be rebuilt to transmit generation currently available. Next, they focused on the priority projects, which are “green field projects,” or new lines that needed to be built to deliver the energy from existing generation sources. Finally, crews began work on subsequent new lines, which are designed to ensure transmission capacity for planned and future wind-generation projects. Oncor plans to wrap up construction by the end of 2013.

Throughout the course of the project, Oncor has worked with a variety of contractors, many of which the utility has partnered with on other projects. To name just a few, Oncor's construction partners include Chapman Construction, McCurley Enterprises and Weaver Construction. For its right-of-way services, the utility partnered with Universal Field Services and Contract Land Staff, while Sam Inc., Sempco, M&S Engineering and Gorrondona & Associates provided ground-surveying services. POWER Engineers provided engineering and right-of-way and construction management support, and Fugro Consultants Inc. and TEAM Consultants Inc. handled the geotechnical aspects of the project.

Rather than working on just one project at a time in a single area, Oncor instead assigned its contractors to simultaneously work on multiple projects in different areas. This approach has required a great deal of coordination and communication since the projects are in various stages of completion.

While individual projects may vary slightly, each project follows a similar process. Oncor first sponsored more than 30 public outreach meetings in the local community to gather feedback from landowners. Then, the utility conducted the line routing and siting, and performed ground and aerial surveys. Oncor turned to its contractors to perform right-of-way acquisition and geotechnical investigations to determine the soil content and design the proper foundations. At this point, Oncor also focused on environmental mitigation or avoidance, engineering and design, and material procurement. Next, crews focus on installing foundations, assembling and placing structures, pulling conductors and energizing lines.

Constructing Steel Structures

One of the most intricate pieces of the CREZ lines is the lattice steel structure, which is made by Falcon Steel from environmentally friendly recycled-in-Texas steel, supplied by Nucor. These steel structures are designed with safety thresholds to stand up to extreme conditions and severe weather events, and are expected to last for several decades.

Though they stand at more than 100 ft tall, each lattice structure starts in several pieces. To assemble the structures, linemen lay down the pieces on the ground. Next, they assemble the tower like a jigsaw puzzle, with each piece going in its proper place. When they are finished, they have a complete tower laying on its side on the ground. They then work on preparing the foundations and raising the towers with a crane. The structure is then held into place over the foundation, and then it is bolted into place. Typically, it takes 10 to 15 linemen to assemble and erect one structure. Though the towers are large and complex, through on-the-job training and extensive practice, contractors have learned how to assemble and set them quickly and efficiently. In fact, one crew set 19 towers in one day — or one tower every 26 minutes.

In addition to installing the steel lattice structures, based on feedback from landowners and under direction of the Public Utility Commission of Texas (PUCT), Oncor is installing monopole structures, supplied by FWT and Sabre. The decision about whether to go with lattice steel or monopole structures is made by the PUCT. In most cases, lattice steel is more efficient and economical for Oncor because of labor and material advantages. The steel lattice structures typically are installed more than 1,000 ft apart with only about five structures in a mile. Alternatively, it takes eight to 15 tubular structures for each mile of line. However, as allowed by the PUCT, Oncor tries to accommodate monopole requests by landowners when possible.

Tapping into Tools and Technology

Since Texas' CREZ initiative is the first of its kind in the state, utilities have turned to some new and existing tools throughout the duration of the project. To improve the productivity of the field crews while constructing new poles and towers, Oncor invested in a geographical information system. This new system helps the company manage spatial as well as nonspatial data. Crew members can conduct field updates to the system in real time by simply logging on to the Internet on their laptop computers and posting reports at the end of the day. The Program Management Office then takes this data, generates status reports and shares those reports with the PUCT, Oncor executive management and other stakeholders.

To further enhance efficiency, Oncor partnered with System Control to provide a prefab control center inside of the station. The control center is delivered from the manufacturer in two pieces with all of the wiring ready for connection. As such, they are able to install these control houses efficiently.

Additionally, line crews use large drilling rigs to drill holes in the various types of hard rock in western Texas. In rock, crews don't need to dig as deep of a foundation — sometimes it can be as shallow as 5 ft. However, if there is sand or soft soil content, crews may need to dig more than 40 ft deep and add bells on the bottom for extra stability.

Confronting Challenges

Like any construction project, CREZ has had its share of obstacles for Oncor and its contractors. With projects in western, northern and central Texas, linemen encounter everything from deserts to rocky terrain, bluffs, rivers and heavily forested areas. In some cases, the field crews have even had to contend with bogs or swamps, which can make access to the worksite challenging. However, each new challenge presents its own opportunity to create an equally unique solution.

For instance, if crews aren't able to get to the work site because of the terrain or another type of physical obstacle, they'll try to secure off right-of-way access or temporary construction easements that allow them to access the land from the other direction. They also put down specialized mats from a variety of suppliers so that the vehicles can safely cross swamp-like areas. Vehicles with large tracts instead of wheels also help the linemen access the muddy, boggy and sandy areas.

Texas weather also can present significant challenges for the field crews. For example, the ground may be solid and hard on one day, but if the area's hit with a rainstorm, it may quickly turn into a swamp. At that point, trucks can get stuck, and workers may be up to their knees in mud.

Oncor also received a large number of line reroute requests from landowners. Oncor worked hard to process and implement these requests whenever possible. In some cases, this led to an increase in the line length, requiring additional materials and revised designs of center-lines and tower heights.

In a state as large as Texas, the terrain, environment and wildlife can vary widely from one county to the next. Throughout Oncor's CREZ projects, the utility identified federally listed threatened and endangered species habitat, and when possible, avoided those areas. In the case of the Black-capped Vireo and Golden-cheeked Warbler (two endangered birds found along the planned CREZ corridor), Oncor mitigated impacts to habitat by purchasing conservation easements in accordance with Oncor's Incidental Take Permit and Habitat Conservation Plan approved by the U.S. Fish and Wildlife Service. The land was specifically set aside to preserve the habitat of these endangered species in perpetuity.

Focusing on Safety

Safety is one of Oncor's top priorities. Each job starts with a daily tailboard session, which may be updated throughout the day as conditions change. In this discussion, crews talk about heavy equipment they will be working with that day, different types of personal protective equipment needed for the project, weather conditions and local terrain. They also discuss individual job assignments as well as any safety concerns associated with working near energized circuits.

Occasionally, there have been cases where crews have performed work over energized lines. In these instances, Oncor employs specialized crews that are trained in this type of work. The teams take special care in these instances by setting up guard structures to prevent lines from falling down on the energized lines if the conductor is dropped. They also follow the state and federal regulations for working live, and never work without their protective eyewear, sleeves and full personal protective equipment.

To provide an additional layer of safety, field crews are also required to use fall protection. The linemen have a D-ring, hook and a lanyard, and belt in and clip to the protective restraint system any time that they are off the ground. If they were to fall, they would only drop about 1 ft to 2 ft.

Since the CREZ project began, Oncor has required its contractors to follow its own internal company policy of 100% fall protection. The contract linemen are allowed to use their own type of fall protection device as long as it meets certain safety specifications.

Delivering Materials to the Field

Due to the sheer size of the project, Oncor has been working with its supply chain organization to partner with suppliers and ensure materials are delivered on time to the proper field location. Oncor's Program Management Office and material managers also help to track all the material on a day-to-day basis. They work closely with field crews to ensure that when they are ready to do the work, they have the materials and the tools to get the job done.

An additional challenge with CREZ is that Oncor hasn't been able to secure the right-of-way in a linear fashion. This has forced crews to have to jump around the project area, requiring contractors and managers to closely monitor materials on a day-to-day basis.

Positive Impact of the Project

The CREZ project has made a lot of positive impacts in the Lone Star State. In addition to fostering new jobs and economic development across Texas, it has an impact on the environment while also supporting a more robust power grid.

When the project is completed in 2013, it will enable the transmission of more than 18 GW (or 18,000 MW) of power from western Texas and the panhandle to the metropolitan areas of the state, adding additional clean energy to the grid and improving air quality. In addition, it will provide the necessary infrastructure to meet the long-term needs of Texas' rapidly growing areas.

It also will reduce the west-to-east congestion in Texas, expand the electrical footprint and provide increased siting location options for all forms of future generation. Even though the CREZ lines are designed in part to carry wind energy, they can be used to increase availability of power from cleaner natural gas or other energy sources.

By building out the new transmission lines, Oncor is able to leverage the clean, green energy from wind farms and create a more reliable power system for generations of Texans to come.

Acknowledgements

Oncor would like to acknowledge other valuable suppliers: HD Supply, Hubbell Power Systems, Siemens and Southwire.

Ed Wingo ([email protected]) is Oncor's CREZ PMO manager, providing construction, engineering, sourcing and right-of-way acquisition oversight, program management and reporting. He holds a BS degree and a MBA degree. He has an E.I.T. Certificate from the Texas Board of Professional Engineers and is an active member of the IEEE.

Fast Facts

Companies mentioned:

Oncor's CREZ project includes more than 1,000 miles of transmission lines, 800 of which are brand new.
More than 1,100 property easements were acquired from Texas landowners along the lines.
In one day, teams set 19 lattice steel towers, or one every 26 minutes.
Oncor has more than 1,000 contract crew members constructing lines in 40 counties across Texas.
To gain landowner input, Oncor hosted 33 community outreach meetings with more than 3,800 attendees.
Oncor is investing $2 billion in its CREZ projects.