A Look at a Utility-Scale Solar Site Plan

Understanding how to analyze and plan utility-scale solar sites has become increasingly critical, with over 195 GWdc of utility-scale solar projected to be added to the U.S. power grid between 2024-2029 (Source: SEIA Solar Market Insight Report Q4 2024). 

In this quick walkthrough, John Selby, instructor of the new course “Utility-Scale Solar PV Design Applications,” breaks down the key considerations shaping large-scale solar development – from setback requirements and fencing boundaries to equipment placement and electrical design. By following this systematic approach to site evaluation, developers, engineers, and stakeholders can better navigate project complexities while optimizing land use and system performance.

Tune into the video with the transcript below. 

In this graphic, we’re trying to identify exactly how much capacity we could put on the site based on a fixed parcel boundary.  The first thing we want to do is look at the AHJ setbacks.This is typically found in the zoning ordinances, which might say you need a 50-foot setback from the parcel line, or maybe 100-foot, or maybe it’s 500 feet from the road, which will vary from municipality to municipality.  

Next up, we’re going to look at our fencing boundaries. As you can see here, sometimes the fencing is the exact same line as the setback.

In other places, we may need to hold it back a little bit further, for instance, if the utility requires all of their interconnection facilities to be outside of the array fence.  

Next up, we’ll need to design our access roads. Access roads are typically dictated by the utility, the local AHJ fire department, or owners.They’re a great idea on any utility scale project as they allow easy access to equipment.  

The next step will be identifying any civil exclusions. This could be any number of things, including wetlands, unsuitable soil, steep terrain, rocky soils, corrosive soils, or even planned areas that we need for stormwater runoff. Regardless, we will know we cannot put arrays or equipment pads in those areas.  

Next up is equipment areas. This is making sure that we leave space for major electrical equipment. This could be as large as a substation or it could be smaller pads, but we want to locate them in strategic locations that are near the access road and not too far in a corner where they’re going to be hard to reach. We also want to space them relatively evenly throughout the site, so that we’re making long runs in medium voltage cable, not DC string wire, combiner box output wire, or low-voltage AC conductors. 

From there, we’re going to start to look at array design from a pretty ideal standpoint. So this is assuming we have a flat and level site with no shading or any other issues. We’ll want to dial that in first, before we start taking away any arrays for suboptimal site conditions. 

One of the things we’ll look at is shading. So, if you have a tree line to the south of your project, which can’t be cut down, you may need to remove modules in that area. 

We’ll also look at slope adjustments.If you have some steep terrain up here, you might say it’s not worth it to install modules in that area either.  

Our last step will be electrical design. Obviously, this is a really simple schematic, but electrical design is very involved for a utility scale project, including medium voltage conductors from equipment pad to equipment pad and at the interconnection area, as well as throughout the array. 

Then you’re done! Utility-scale design in under five minutes. I’m hopeful that this graphic kind of gave you a high level understanding of what we’ll be covering this course, and I’ll revisit it in the various modules to kind of jog the memory about where we are in the overall arc of the project.

Want to dive deeper into these aspects of utility-scale solar design? Enroll today in the Utility-Scale Solar Engineering bundle.