PROJECT
Ashtabula II Wind Farm Foundation Retrofit: Precision GPR Scanning and Core Drilling
WATCH THE WORK IN ACTION
PENHALL'S ROLE & EXPERTISE
Penhall was selected to support the structural retrofit of 33 wind turbine foundations at the Ashtabula II Wind Farm in Luverne, ND. Working under Landwehr Construction for owner Otter Tail Power Company, Penhall performed extensive GPR scanning and high-volume precision core drilling to support reinforced concrete collar installations. These retrofits were essential for upgrading turbine load capacity as part of a wind farm repowering initiative—extending the life and output of existing infrastructure.
Precision GPR Scanning: Located rebar and structural elements throughout the work area to ensure accurate, damage-free drilling.
High-Volume Core Drilling: Completed thousands of 1-3/8” diameter holes up to 4 feet deep to support structural retrofit requirements.
Customized Equipment Use: Deployed specialized tools to meet strict tolerance and depth requirements on all foundations.
Structural Integrity Support: Enabled installation of reinforcing dowels for new pedestal collars to strengthen turbine towers.
Reliable Wind Market Partner: Demonstrated Penhall’s expertise in supporting repowering projects with safety, accuracy, and efficiency.
LOGISTICS & PROJECT EXECUTION
Penhall’s expertise in large-scale, high-precision drilling projects was essential to the success of the Ashtabula II Wind Farm Foundation Retrofit. Working under tight turbine shutdown windows and in a remote location with unpredictable weather, our team maintained efficiency and safety without compromising quality. Through meticulous planning, redundant equipment strategies, and seamless coordination, we supported the structural upgrades critical for the wind farm’s repowering efforts.
Key milestones achieved included:
Completed over 45,000 linear feet of precision core drilling across 33 wind turbine foundations
Scanned 15,000+ square feet of foundation surface
Maintained a strict rotation schedule, with only 10–12 turbines offline at a time
Deployed redundant equipment and a mobile repair unit to prevent downtime in remote, weather-impacted conditions
Coordinated multiple experienced crews working extended hours, six days a week
Completed ahead of schedule and within budget, with zero safety incidents
Penhall’s commitment to operational excellence, safety, and adaptability allowed us to deliver outstanding results in a challenging environment. Our ability to meet strict deadlines and technical demands reinforced our reputation as a trusted partner in the power and wind energy market.