T&D World Magazine
EldoradoIvanpah Desert Transmission Southern California Edison

A 35-mile double-circuit 220-kV transmission line was installed as part of the Eldorado-Ivanpah Transmission Project to accommodate power from new solar developments. Construction in this sensitive desert landscape along the southeast California-Nevada border required meeting strict environmental mandates.

Southern California Edison's Eldorado-Ivanpah Transmission Project

Southern California Edison combines technology and teamwork to meet challenging environmental requirements on the Eldorado-Ivanpah Transmission Project.

Several abrupt mountain ranges surround the desert landscapes of the Eldorado and Ivanpah valleys, where aprons of sediment slope down to scrub brush and several dry lake beds in the valley bottoms. This fragile desert habitat along the California-Nevada, U.S., border is home to several protected species such as the desert tortoise and presents numerous challenges that make it hard even to contemplate a major transmission line through this region.

However, the sun that shines in the Ivanpah Valley also is ideal for new solar generation projects, with up to 1,400 MW of solar development coming on-line over the next few years. This new solar generation will help California utilities like Southern California Edison (SCE) to meet the state’s ambitious renewables portfolio standard, which requires 33% of generation from renewable sources by 2020.

SCE’s existing transmission facilities, including a 35-mile (56-km) single-circuit 115-kV transmission line, were inadequate for this anticipated development, which is how the Eldorado-Ivanpah Transmission Project was born. The project crossed lands managed by the Bureau of Land Management, which required SCE to implement some of its most aggressive and proactive environmental and safety programs to date, encompassing environmental monitoring, training, inspection and overall agency communication. All of this was achieved under an accelerated 18-month project schedule to meet a deadline for on-line generation testing of three new solar partners’ solar-generation facilities.

The end result was a successful project that leveraged technology and teamwork to achieve project goals under a series of demanding constraints. Using a state-of-the-art Web-based platform known as POWER360 as a portal to access and integrate complex project data for quick decision making, the team was able to achieve a collaborative approach with regulatory agencies that resulted in substantially quicker response times than SCE typically has experienced, effective adjustment of plans in the field to continue construction even during heightened bird activity season, and significantly above-average safety results. Taking these results to heart, SCE plans to use similar approaches for future project development.

Strict dust control measures were implemented to avoid disruption of protected desert bighorn sheep.
Strict dust control measures were implemented to avoid disruption of protected desert bighorn sheep.

Project Challenges

SCE filed an application for approval with the California Public Utilities Commission in May 2009 and an initial application with the Public Utilities Commission of Nevada in April 2010. The Eldorado-Ivanpah Transmission Project includes five major components:

  • A new 220/115-kV Ivanpah substation in San Bernardino County, California, just across from Primm, Nevada
  • Replacement of an existing 115-kV line with a 35-mile double-circuit 220-kV line with optical ground wire cable
  • Upgrades at the Eldorado substation near Boulder City, Nevada
  • Construction of two alternate telecommunications pathways as well as other equipment to connect the project to SCE’s existing telecommunications system
  • Installation of a total of 211 lattice steel towers and 10 H-frame steel pole structures.

SCE hired POWER Engineers to design the new transmission line and perform owner’s engineer/construction management services. The construction contract was awarded to PAR Electrical Contractors in August 2012, and SCE received notice to proceed from the California and Nevada utility commissions the following month.

The team faced several significant challenges:

  • SCE was issued a permit under the Endangered Species Act that would allow up to two incidental takes of desert tortoise, a threatened species that is concentrated in the valley. Other projects including solar plant construction had been stopped as a result of too many takes, and regulatory agencies limited SCE to no more than two takes because of concerns that previous mitigation plans had not been restrictive enough and additional construction could further harm the species.
  • Any bird nest — defined as two sticks on a structure or ground — would stop all project activity within a specified buffer under California’s interpretation of the Migratory Bird Treaty Act.
  • Use of helicopters to fly in preassembled lattice towers would require consideration of dust control issues and potential disruption of protected desert bighorn sheep.
  • Extensive watering and dust monitoring would be required in the two states’ water-restricted areas.
  • Species previously thought to be nonexistent in the area were found, including the Mojave green rattlesnake, which is considered to be the most poisonous snake in the United States, the burrowing owl and the American badger.
Small helicopters are used to fly in tools and personnel, set stringing dollies and string conductor from structure to structure.
Small helicopters are used to fly in tools and personnel, set stringing dollies and string conductor from structure to structure.

Bringing It All Together

The intensive effort to meet environmental requirements began right from the start, with a goal of fostering a culture of strict compliance, forward thinking and collaboration with the regulatory agencies. The first step was establishing the owner’s engineer/construction manager as the single point of contact for construction as well as environmental procedures and requirements. Other measures were as follows:

  • Mobilizing POWER’s Web-based collaboration tool, called POWER360, to enable sharing of daily project status, geographic information system (GIS)-linked bird nesting areas and bird buffers, map-linked field pictures, detailed reporting, and action items between SCE, the regulatory agencies, PAR and POWER
  • Using PAR’s GPS-based helicopter navigation system to automate the communication of latitude and longitude locations of nest locations and buffers through GPX files — a common GPS data format — to avoid disturbances
  • Implementing rigorous procedures and training to minimize impact to protected species, and to prevent any injuries or fatalities to workers
  • Creating a communications plan to expedite responses to design requests for information and project adjustments as well as overall decision making
  • Establishing a rapid-response resource committee to address field issues related to monitoring, permitting, mitigation and compliance.

The result of all this planning and coordination was readily apparent after construction began in September 2012. At any given time, approximately 100 environmental professionals were working on the project. Some were assigned to crews to do a sweep of each work site daily for sensitive plants and cacti, birds, tortoises, owls and other protected species in the proposed work sites. They reported their findings to the lead environmental person on site.

Spotters were assigned to large vehicles where seeing over the hood to spot any desert tortoises would be difficult. Detecting these tortoises can be hard, as they range in size from a silver dollar up to 15 inches (25 mm up to 381 mm). They also are the color and appearance of desert rocks. Any violations, such as speeding, driving off designated corridors or failing to look under parked vehicles before driving, would be reported to the lead on site. Stand-downs or holds could be called to deal with violations.

Monitors were assigned to look for bird nests or nesting behaviors. A rapid-response team was mobilized to report the coordinates of any potential nest, log the nest on POWER360, upload the location to working helicopters, send the location and coordinates to construction crews, and immediately send a request form to the regulatory agencies. PAR would submit a workaround plan with drawings to POWER, which would then send the request to SCE and, in turn, the agencies. The agencies would review the request and return an answer within 24 hours. Historically, on other similar projects, agency response time was measured in number of days or weeks.

Special dust monitors watched for proper watering and ensured excessive dust was not generated from vehicles and equipment. Dust monitors attended a two-day class on detection and recognition methods.

The result of all that activity was no desert tortoises were injured or killed during the project, construction never stopped and the project stayed on schedule during the height of bird activity season. General agency response time was reduced from a 30- to 45-day range to a 3- to 5-day range, and a 24-hour turnaround for bird nesting workarounds became the norm using the POWER360 tool as the communications platform for all parties.

Working from platforms known as spacer buggies, linemen install spacer dampers to prevent subconductor contacts and to limit conductor vibration.
Working from platforms known as spacer buggies, linemen install spacer dampers to prevent subconductor contacts and to limit conductor vibration.

Other Desert Obstacles

Challenges from the desert environment were not limited to regulatory restrictions alone. There were several other technical design and construction challenges. Soil conditions and topography affected road construction, foundation construction, tower assembly, conductor stringing and work site access. Geological conditions in the region included alluvium fields, volcanic soils, sand, dry lake beds and granite cliffs. The alluvium fields required large drill rigs to lift larger stone.

Where volcanic soils existed or rock fissures were common, a foundation design known as a micropile was used. Micropiles use special rods and grout to anchor the foundation. They allow for solid connections in areas where fissures can grow and regular drill application for steel-pole foundations is not practical.

Vehicle traffic through McCullough Pass is restricted, and installing structures is almost impossible and dangerous. PAR Electric used Sikorsky S-64 Skycrane helicopters to fly in preassembled lattice towers. Smaller helicopters also flew in tools and personnel, set stringing dollies and strung conductor from structure to structure. Fueling sites had to be predetermined and approved by the regulatory agencies.

On top of hills, in dry lake beds and within wash perimeters, straw wattles — tube-shaped erosion devices — were required around each 250-ft by 250-ft (76-m by 76-m) work area.

A number of off-road race events occurred during the project, crossing the alignment, and requiring planning and coordination to avoid public hazards and work stoppage.

The desert iguana (Dipsosaurus dorsalis) is a common species found in the Mojave Desert region of the Eldorado and Ivanpah valleys.
The desert iguana (Dipsosaurus dorsalis) is a common species found in the Mojave Desert region of the Eldorado and Ivanpah valleys.

Safety Under Control

The expedited work schedule also raised the possibility that safety could be a challenge, but proactive planning facilitated management of this primary concern. POWER was assigned as the responsible safety coordinator on site, with SCE as the safety lead. POWER established a safety incident deterrent team with representatives who could address all aspects of the field work. The team’s primary mission was to be proactive in heading off safety incidents by working with the contractor safety team in evaluating safety challenges and ensuring corrective action.

Field observers also were present on site, providing an additional level of accountability. The result was a days away, restricted and transferred (DART) rate of 1.52 per 659,964 man-hours worked, which is significantly better than the national industry average of 2.10 for similar work and man-hours.

A Sikorsky S-64 Skycrane helicopter flies in preassembled lattice towers.
A Sikorsky S-64 Skycrane helicopter flies in preassembled lattice towers.

Taking Teamwork to New Levels

The lesson that soon became apparent from this project is that it is necessary to be proactive to get ahead of project constraints, particularly when it comes to meeting environmental challenges that can slow or stop construction. Having a comprehensive daily picture of project status, sharing GIS-linked project information and coordinating with field personnel in real time have all become critical tools for project success. Extensive preconstruction training and planning also are necessities.

Having a single point of contact guiding the team through environmental challenges and a state-of-the-art digital platform that allows a single-source view of project information for fast, informed decision making proved to be decisive in achieving project goals. Regulatory agencies were integrated into the construction process to an unprecedented extent. They were given restricted access to the POWER360 site so they could download bird nesting information and other project details directly. The POWER360 site registered more than 1,500 hits in just one day, showing how extensively used it was by both the internal team and external stakeholders.

What stands out about this overall effort is how SCE, PAR, POWER and the regulatory agencies worked together successfully to address the steep environmental requirements and challenges head-on.


Roger Schultz ([email protected]) is a senior project manager for the Major Projects Organization’s northeast territory at Southern California Edison Co., a publicly owned utility. Schultz has 33 years of experience in the utility industry licensing, constructing and managing substation and transmission projects. His current projects include Silver State South and Eldorado-Ivanpah Transmission Project.

William Jerry Silva ([email protected]) is a senior project manager for the Major Projects Organization’s northeast territory at Southern California Edison Co. Silva has 31 years of experience in the utility industry managing major licensing for substation and transmission projects, and having served in key roles during the energy crisis. His portfolio of projects includes the Kimball, Triton and Leatherneck substations in addition to Silver State South and Eldorado-Ivanpah Transmission Project. Silva has been involved with all major local, state and federal licensing permits for Eldorado-Ivanpah Transmission Project during the last five years.

Bill Hanna ([email protected]) is a senior project manager for POWER Engineers Inc. He has 36 years of experience in the utility and consulting sectors licensing, constructing and managing substation and transmission projects. Hanna represented Southern California Edison Co. as its owner’s engineer on the Eldorado-Ivanpah Transmission Project.

Companies mentioned:

California Public Utilities Commission | www.cpuc.ca.gov/environment/info/ene/ivanpah/ivanpah.html

PAR Electric | www.parelectric.com

POWER Engineers | www.powereng.com

Sikorsky | www.sikorsky.com

Southern California Edison | www.sce.com

 

 

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