Ulteig Designs Collection and Transmission System for Largest Clean Energy Infrastructure Project in U.S.

Corona, New Mexico

• 377 Wind Turbines

• 67 Miles of 345 kV AC Transmissions Lines

• 1,050 MW of Power

Ulteig was hired by PATTERN ENERGY to design a system to collect energy from the 377-turbine Western Spirit Wind Projects through four collection substations. Electricity would then be transmitted through 67 miles of 345 kV AC transmission lines (the GenTie Transmission) to the 155-mile Western Spirit Transmission line. The collection substations were designed with power metering equipment that meets the California ISO (CAISO) metering requirements.

When construction is completed, 1,050 MW of power will be transmitted from the Western Spirit Wind Project, which consists of four wind farms situated across the counties of Guadalupe, Lincoln and Torrance in central New Mexico. The wind farms are approximately 292,000 acres of land held by 40 landowners. Having just one consultant, Ulteig’s design services ranging from COLLECTION SYSTEM DESIGN, SUBSTATION DESIGN, TRANSMISSION LINE DESIGN and CAISO METERING DESIGN, allows all aspects of the design to seamlessly change when necessary. Ulteig engineers sought to drive down costs while staying on-budget and within the construction schedule as they navigated the remote terrain of central New Mexico.

With a project so large and complex, the Ulteig Transmission and Distribution, Substation and CAISO teams faced several challenges while designing and engineering this project.

Collections – With 377 Western Spirit wind turbines, which offer a capacity ranging between 2.3MN and 2.8MW, spread out over a three-county area, the Ulteig Transmission and Distribution team sought to find the most advantageous routes to lay underground collection cables. The team was able to limit trenching to 285 miles.

CAISO Metering – Based on power purchase agreements, which would involve distributing power from the project outside of New Mexico to California, Ulteig involved its CAISO metering team, which determined that the project would require 46 meters (double the number of a typical project) due to the complexity and scale of the project.

Transmission Lines – With the 67-mile gen-tie transmission line system structure in this part of New Mexico, the Ulteig Transmission and Distribution team contended with rocky terrain as well as still-changing easements, which meant that some pole locations could shift as much as 150 feet either way from a proposed location. To consolidate the schedule, the team worked closely with the power line power manufacturer to select 490 poles from their internal library. The team also leveraged various geographic surveys and other sources to optimize pole placement.The Ulteig design for the Western Spirit gen-tie transmission line also had to consider the farmers and ranchers who would be impacted. The project easements are on land that still belongs to the landowners and can be used for activities such as farming, grazing and other activities that do not interfere with the operation of the line. The Ulteig design therefore had to include sufficient clearance under the transmission lines to grow crops and operate standard farm equipment.

Substations – In designing four 34.5/345 kV collection substations, the substation team faced the issue of balancing costs with building for flexibility.“With a project of this size and scale, it was critical to come up with a plan that allowed for future options,” said TJ Severance, P.E., a technical manager with Ulteig’s Substation team. “Flexibility was very important. We needed to think 10 and 20 years into the future.”

The Ulteig team utilized a daisy-chain design to reduce transmission line, construction costs and long-term maintenance costs. Three southern substations were wired together to reduce the gen-tie transmission line length. Additionally, underground cabling between turbines was reduced.

The key to Ulteig’s success on this project lies in the close collaboration between its different teams and with its clients.

From planning and studies to full design and engineering services like commissioning, and every phase in between, Ulteig is your one-stop shop. Learn more about Ulteig’s POWER and RENEWABLES Lifeline Sectors now!

*Photo(s) sourced by Pattern Energy.