Challenging site conditions
The Bonanza Solar Plant (Bonanza) is located in Bonanza, Oregon. The 6.8 MWDC solar plant was acquired from leading US developer, Cypress Creek Renewables, LLC, as part of a transaction for a portfolio of utility-scale solar PV plants located in North Carolina and Oregon.
But before the plant could go operational some rocks had to be moved and holes for the foundations had to be pre-drilled.
Foundation installation
Before piles could be driven we had to go through this process:
- Drill a 10” hole centered at the location for the foundation to required depth using a drill rig.
- Backfill hole with approved backfill material compacted at a minimum of 24” lifts.
- Drive posts at location of newly compacted material.
- Test the uplift and lateral load capacity of new piles. This has to be done on a certain amount of piles.
- If all piles pass – start full production.
9891
Hours of Work
August 2018
Construction Date
6.8
Size[MW]
Bonanza
Location
Sunflower
The Sunflower from RBI is a single-axis tracker design, which uses a gearbox design at each pile to reduce stresses and provide tracking stability at each foundation. This engineering feature allows for lighter components to be used in the structure’s design, making for a simplified installation in the field.
Completion
This project was quite challenging. We had to commute quite a bit to get to the job site. The site was broken up into 3 different areas – one of them being on a plateau overlooking the other ones, so keeping the team organized and getting the supply to them was not straightforward. Then there was the subsurface challenge as described above. The good news was that we had decent weather during construction which helped tremendously!
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