Water Mission/Bahamas Water & Sewage Corporation
Racking System: Ground Fixed Tilt
Structure Type: Municipal
Location: MARSH HARBOUR, BAHAMAS
Completed: June 2021
Challenge
Caribbean islands present unique challenges for solar PV installations. Given frequent hurricanes with 160-mph winds and the often loose soil, ground mount solar in these areas must be especially carefully designed. Water Mission approached Unirac with a site in a remote, rural region where water supply equipment necessitated a solar power component to help the area recover from 2019’s Hurricane Dorian.
Soil conditions were predominantly sandy, which makes foundation-based solutions difficult. In addition, most conventional equipment (e.g., pile drivers) could not be employed due to the rugged terrain.
Solution
Unirac’s team, led by Senior Civil Engineer Jon Schermerhorn with years of hands-on ground-mount experience, created an optimized Ground Fixed Tilt (GFT) design that withstands extreme wind conditions using an eight-rail design and above-grade ballast blocks, avoiding the need for foundations. The solution was validated by 3rd-party verification of the system design. Schermerhorn’s experience helped the customer work through options and choose a lesser-known solution that was ideal for the project.
This was also a first-of-its-kind project for Water Mission, blending the electricity from the solar array with power from the grid. The scale of the job made having engineering experts to turn to especially valuable.
Implementation
Our custom solution required extensive project communication, with phone calls several times per week, to facilitate a smooth installation. Unirac was ready throughout to help talk through proper tolerances and construction methods for the unusual setting. Our veteran team was able to make the process painless.
I’M DEFINITELY IMPRESSED. JON (SHERMERHORN, CIVIL ENGINEER AND SOILS SPECIALIST) HAS BEEN WILLING TO TROIUBLESHOOT WITH ME, WHICH HELPS IN A CONSTRAINED RESOURCE ENVIRONMENT WHERE THE SUPPLY CHAIN WAS DEVASTATED. HE’S BEEN ABLE TO TALK ME TRHOUGH A LOT OF THE WHY’S”. ALL IN ALL, IT HAS BEEN GREAT.
Brian Graham, Project Engineer for Water Mission
Benefit
Water Mission completed its project with two GFT solar fields (121kW and 219kW), each using an above-grade design that ensured climate conditions were met while also facilitating installation. Graham said it was the organization’s largest installation to date.
