Solar Generation Interconnection Studies Help Deliver Clean Energy to Millions of Customers

The Client

Our client is a southern-based utility provider serving millions of customers nationwide.

The Challenge

The organization receives applications from solar companies seeking to connect their generation facilities to the client’s transmission system. Approval of these applications depends on interconnection (IC) studies, which assess system strength, breaker duty and protection requirements. As the number of solar facility applications grows, so does the demand for these studies. To keep pace, the client needed an engineering services provider capable of completing studies efficiently and within strict timelines. Meeting these deadlines was critical, as delays could increase costs and reduce returns.

The Actalent Solution

The client selected Actalent as its first external engineering partner to deliver these studies. To address these challenges, Actalent deployed a team of engineers to learn the client’s processes and modeling techniques for incorporating solar sites into its CAPE model, which is used to evaluate the impact of proposed facilities. The team also developed a strong understanding of the client’s protection standards to ensure consistent and accurate recommendations during study reviews.

Interconnection studies fall into three stages, each providing increasing levels of detail to determine costs:

1. Feasibility studies: offer an initial estimate of interconnection costs
2. System impact studies: provide more detailed cost insights based on required system upgrades
3. Facility studies: deliver final, highly precise interconnection cost estimates

Each study includes the following components:

• System fault availability and Thevenin impedance analysis
• Breaker duty evaluations for equipment near the proposed interconnection
• Weighted short circuit analysis to assess system strength
• Protection requirements for relaying schemes that must be added or modified to integrate the new generation source

Flexibility and adaptability were critical to success. The team accounted for system changes resulting from earlier applications when completing studies for new ones. Analyses were performed not only for the interconnection year, but also for future planning horizons. Data quality and availability presented another challenge. The engineers developed expertise in modeling system components accurately, even when working with estimated or typical values, ensuring reliable study results. As work progressed, Actalent’s experts established and continuously refined a standardized study process. This improved both efficiency and accuracy, ultimately delivering consistent, high-quality results while reducing overall study costs for the client.

The Results

Over the past three years, Actalent’s team has successfully completed approximately 125 studies under this project. Deliverables have included comprehensive reports, a final database encompassing all modeled study components, and ongoing support for follow-up questions and additional study scenarios. By integrating data with our reports, we have produced complete study results that can be effectively shared with the client’s customers.