CLIENT: Various LT2 Clients
PROJECT DESCRIPTION:
PRI provided on-site support for the CarbonFree Technology LT2 Projects, completing geotechnical investigations and foundation load testing activities for utility-scale solar developments. Drawing on extensive experience across renewable energy projects in Canada, the United States and the Caribbean, PRI applied proven investigation methodologies to deliver the subsurface information needed to reduce foundation-related risk and optimize design.
CHALLENGE:
Utility-scale solar projects carry significant foundation installation risk due to the sheer number of foundations required across variable subsurface conditions — including differing soil types, groundwater, and shallow bedrock. Beyond the solar arrays themselves, major electrical infrastructure such as substations carries substantially greater foundation loads, requiring a deeper and more detailed understanding of ground conditions to avoid costly over-designed foundation which add unnecessary capital expenditures.
APPROACH:
PRI implemented a multi-phase investigation and testing program tailored to the site:
- Solar array and substation investigations: Standard array foundation investigations were paired with deeper, targeted boreholes at proposed substation and major equipment locations to characterize subsurface conditions under higher foundation loads.
- Helical pile probing and testing: A series of helical probes were distributed across the site to develop a depth-versus-torque profiles, flag areas of installation difficulty, and inform constructability. Representative helical test piles were then installed and subjected to axial and lateral load testing to validate design assumptions and allowing for further optimization. Axial capacity typically governing the overall length of the foundation in this northern climate due to frost uplift; but considerations of lateral capacity must still be considered and cover the overall shaft size which is primarily impacted by wind loading.
- Driven pile evaluation: Driven foundations are still the most economical choice for the support of solar racking systems, but may not be feasible due to the increased embedment depth to resist frost uplift. Using the helical probing and geotechnical data, driven pile test locations were selected to compare the performance of W-section and HSS round foundations and ultimately compare to them to the performance of the helical pile option. Installation data (including drive time by depth) were correlated with subsurface findings, and all test piles underwent axial and lateral load testing to confirm capacity and constructability.
OUTCOME:
The combined probing, installation monitoring, and load testing programs allowed PRI to validate foundation performance, confirm constructability across the site, and optimize the final foundation configuration ahead of full-scale production. This proactive, data-driven approach reduced construction risk, improved cost certainty, and gave the project team confidence that the selected foundation systems would meet both structural and constructability requirements — de-risking the project from a geotechnical perspective before installation began at scale.