Sometimes the most challenging aspect of utility-scale solar or commercial solar installations is not getting the equipment running and connected to the grid. It’s where to put the equipment or how to fit it into a specific plot of land that is irregularly shaped while avoiding the alligators.
This was the case with the recently launched 5.9MW Stanton Solar Farm we designed and engineered for OUC in Orange County, Florida.
The challenge
We were tasked with helping to define the useable area within the client’s property. There were numerous environmental challenges. The design incorporated the use of a single-axis tracker on an irregularly shaped parcel that is prone to flooding. The tracker blocks are large and highly constrained in terms of footprint.
There were also interesting challenges that arose with the stringing plan. A “string” is the the trade jargon for a “Source Circuit”, which is a multitude of solar modules, wired in series, to achieve a desired voltage, nominally 600V. This voltage is limited by the National Electrical Code as well as the operating specifications of the inverter (temperature plays a big role in this limit as well). At Stanton, each panel or racking assembly is comprised of 10 modules, but there were 14 modules per string.
The solution
At first we proposed to break up the tracker blocks into smaller sub-arrays, but this was the least cost-effective solution. The team came up with an optimal block size and ways to trim panels off of the ends of the rows to create a “stepping” of the array that matched the curved edges of the parcel.
Within this optimal footprint, we had to consider the string size and ensure that each tracker was divisible by 14. And the parcel kept shrinking.
As we learned more about the environmental conditions in and around our site, we learned the array would need to be moved as far to the west as possible to allow for a wetland buffer, flood mitigation measures, and possible tree shading along the east and south. This led to multiple adjustments to the layout of the array.
Stringing 5.9 Megawatts in a single day also proved to be an interesting and exciting challenge. But we pulled together and made it happen.
A job with teeth
This is the first PV project that I worked on where alligator intrusion on the site was a factor. The array had to be designed to withstand hurricane force winds, possible flooding, corrosive salt air … and alligators. Not that alligators really pose a threat to PV systems, mostly just the people that are trying to maintain them.
It might only be a small amount of instantaneous power compared to its neighboring coal-fired plant, but in the long term, this system will offset many tons of carbon, which could add up to a significant environmental contribution.