100MW West Coast Solar Project

This solar engineering project, located in central California, presented exciting opportunities for Ulteig. Like wind energy, solar energy makes its way from the original source to collection lines and then to the substation, where the energy exits at a high voltage. We designed the requirements of CAISO (California Independent System Operator), which controls the grid in California and has increased requirements and scrutiny. The interconnecting utility also implements strict design requirements for all projects that connect to their system, and we met these thorough standards quickly.

After receiving Notice to Proceed, Ulteig had its first round of deliverables to CAISO in less than two weeks. We also kept up with multiple submittal due dates and requested content from the various review parties. Our responsiveness and ability to bring a design to the table on short turnaround allowed the project to progress without compromising the schedule or quality of work.

To accommodate a new 22.5 MW Battery Energy Storage System at a large wind energy center, an additional 34.5kV position was added to an existing 34.5/138 kV collector substation. The added position was made via a 1200A, 34.5kV breaker with metering class CTs and corresponding bus and line switches, and the BESS banks were connected with medium voltage underground cable.

No updates were required to the existing electrical equipment enclosure control battery bank; it was utilized and had space to accommodate the additions associated with this project.

Once the controls were updated to integrate the new position into the existing protection scheme, an ION meter was included for frequency monitoring. 

The battery manufacturer was responsible for the design associated with the step-down transformers, inverters, battery systems and corresponding HVAC requirements. Ulteig’s design demarcation was the connection to the 34.5kV/480V step-down transformers.

This battery energy storage system, which helps balance the power grid frequency, went into commercial service in November of 2014.

The substation design presented a unique challenge as the addition to the low side had separate power purchasers, while the delivery to the POI was through a shared transformer and five-mile transmission line. In addition, the wind farm had to operate as a single entity in terms of meeting voltage schedule of the transmission owner at the POI while also having the functionality of handling separate active power curtailment set-points from the independent system operator.

Ulteig provided right-of-way services for this project. Leases were obtained for placement of wind turbines, access roads, transformers, splice cabinets, underground collection lines, substation, and an on-site O&M facility. Lease acquisition of 137 parcels of land totaling approximately 36,340 acres was completed in 14 weeks. The land acquired consisted of farm and ranch land.

The collection system design involved optimizing the route so as to provide the best possible option for both the client and landowners. The 345kV/34.5kV substation contained four feeders, and it was designed to owner standards. Ulteig also provided civil engineering services including access roads, crane access routes, crane pads, delivery flow plan, intersection improvements, laydown yard, substation side, and yard site design services.

The development and construction of a renewable project is extremely time and resource sensitive, and often involves a variety of issues that can affect commercial and operational viability. To keep up with aggressive schedules and the continuously evolving requirements of the renewable industry, you need a partner that is responsive, flexible, and reliable.

Ulteig takes pride in being all of those things. We have experience successfully addressing these challenges so our clients can build and operate viable, sustainable wind and solar projects.

We offer a wide range of services to help at any stage of a renewable project. Leverage our team for a particular engineering scope, or take your project from ground-breaking to final energization with our comprehensive suite of project design and management solutions:


  • Energy estimation Services, including soiling studies, horizon studies and site-specific modeling
  • Preliminary project design and performance engineering
  • Consultation and performance engineering for existing design
  • Project setup to align with organizational goals
  • Interconnection request portfolio management
  • Development activities tracking and management
  • Creation and implementation of tollgate process for development stages
  • GIS
  • Main power transformer specifications


  • Full engineering scope, including civil, SCADA, wind or solar plant and medium/high-voltage infrastructure
  • Turnkey engineering scope management for wind and solar projects
  • Equipment specifications
  • SWPPP, hydrology study, preliminary grading plans
  • Topographical survey
  • Financeable energy estimate
  • Scheduling and project controls
  • Scope of Work definition for project construction
  • IE and financing due diligence support
  • Owner’s Engineer and Owner’s Representative services


  • Construction management
  • Project controls
  • SCADA commissioning, field support and management
  • Performance/acceptance testing
  • Financial close and project closeout support
  • Project commissioning


  • Operations & Maintenance Manuals and onsite training for plant operation
  • Performance monitoring