MARCH 8, 2022

Putting the “E” in Large-Scale EPC Solar Projects

By Mythri Anumula and Paul Guzowski

Borrego’s leadership in distributed and large-scale solar and energy storage engineering, procurement and construction (EPC) may be well known, but a main ingredient of our secret sauce for success deserves a shoutout: the deep bench of technically savvy electrical engineers we’re both proud to be part of.

At Borrego, engineering is deeply ingrained in our company’s DNA. We carefully document processes and technical knowledge, not only so that we can provide the highest quality work for our customers but also so younger engineers can learn and grow from that knowledge. We work in an ecosystem where we’re all talking to each other constantly about our projects, with great collaboration and an open-door policy. If we don’t know the answer or have direct experience in a certain area, someone else on the team is likely to have it. We make sure to carry over all the lessons learned from one project to another. Our entire engineering team benefits greatly from the vast trove of expertise and experience gained from the thousands of projects the company has completed across the country.

Mythri at Belleville, IL project site

Hands-On Throughout Project Life Cycle

Our engineering team is involved throughout the project life cycle, from pre-sales work with developers all the way through the engineering, construction and commissioning process—our job runs from the beginning to the end.

Engineering During Development

Sometimes we start before the customer has even bought the project, whether it’s a Borrego-developed project or developed by another company. We work with the development team on project parameters and identify any challenges and hurdles. Then we bring it into site design, create and stamp all the drawings, and take care of a million other details. We meticulously go through all the engineering calculations to make sure the project meets the customer’s—and our own—standards.

Engineering During Solar Construction

Once we complete the on-paper design phase, we enter the construction phase, where we’ll go onsite to perform electrical inspections and work with all the subcontractors and site superintendents to ensure the project is built correctly to our standards and the design we created. We collaborate with the solar construction team to resolve all the little hiccups that come along in a way that’s still technically sound, keeps it within our budget, and adds value to the project.

How Engineering Works with Utilities

Another big part of our role is working with utilities—and it’s the utility requirements that often make each project unique. As an industry-leading solar and energy storage EPC, we’re building solar and storage plants all over the country, often trailblazing in locations new to solar and storage.

We work closely with the utilities to meet their requirements to keep the grid stable, whether it be the use of certain equipment, specific protective settings, interconnection details or other fine points. Thankfully, part of our toolkit is an engineering/utility matrix filled with utility requirements from across the U.S., which our team updates constantly based on the due diligence and expertise of other electrical engineers across the country.

Meeting national electric code and our customers’ design standards goes with the territory, but utility requirements range from a stringent list of specified and approved equipment to a more open approach to technical issues and equipment choices. The latter is something we see with utilities not as familiar with solar. Because of our experience in different states, we know what questions to ask of the utility and we know what the answers are likely to be.

Case in Point: Belleville Solar Landfill Project

One of the more interesting and challenging projects our team has worked on is located on a closed landfill in Belleville, Ill. Developed and owned by AES and Republic Services (which also owns the landfill), the 13.2 MW-DC ballasted fixed-tilt ground mount system was designed and built by Borrego—one of the largest of its kind in the U.S.

Aerial view of Belleville, IL project site

While we have worked with AES on many projects and with local utility Ameren on smaller, less complicated less than 5 MW systems, it was our first time working with Ameren on a sub-transmission interconnection project in its territory.  Ameren had limited experience with large-scale solar, and Belleville was its first solar landfill project.

During the course of the project, we held biweekly calls with Ameren, sharing our in-house expertise on the large-scale solar design while we gained an understanding of the specific utility requirements. It took a year of close collaboration to finalize specific technical requirements, such as protection schemes and the relay settings they wanted to see before the project reached PTO and the system was ready for witness testing.

Up for the Technological Challenges

One of the challenges on the Belleville site involved the recloser, a utility-scale circuit breaker designed to detect abnormalities and then disconnect the site from the grid. The size of the project required adding the recloser, which is typically not needed in a smaller, more generic solar plant. Ameren didn’t have experience with this type of equipment used on solar plants. They leaned heavily on Borrego to collaborate with them to figure out what anomalies the recloser needed to detect and finalize the required settings. We used our historical experience to educate them and guide them through it—and also took that concern off our customer’s plate so they didn’t have to worry about the utility being unfamiliar with new protection schemes and how they worked.

As with most large-scale solar EPC projects, no two projects are exactly the same. And it’s one of our primary operating principles to collaborate closely with our customers to discover their requirements and deliver what they value. In the case of Belleville, AES’s preferred equipment list included string inverters and transformers we had not worked with previously, as well as a DAS vendor some of our team members were not familiar with. We owned that challenge and did a deep dive into the technology requirements of the equipment to ensure the customer was happy and the project met the safety threshold.

If there’s one final thing we can say about Borrego’s engineering team, it’s that we don’t shy away from new, technologically challenging tasks. As engineers, it’s rewarding to be challenged and work on interesting solar and energy storage projects, especially when that work delivers so much value to our customers. Learn more about our EPC capabilities and connect with us for your next large-scale solar and energy storage project.

Borrego Staff

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