Date May 7, 2025
Memo
To Craig Adair, Crossroads Solar Grazing Center
From Mark Bonifas, P.E., LEED AP
Subject Wind Velocities
Project Number 17078
Verdantas has provided the following information to support Crossroads Solar I, LLC’s preparation of its Certificate Application for an Electric Generation Facility in accordance with Ohio Administrative Code (OAC) 4906-4-08(A)(6)
(A)(6) Wind velocity. An analysis of high wind velocities for the area, including the probability of occurrences and likely consequences of various wind velocities, and describe plans to mitigate any likely adverse consequences.
The Facility is expected and recommended to be designed to withstand typical high wind occurrences, as defined by the local wind speed requirements in the structural design codes at the time of final design. The 2024 Ohio Building Code became effective March 1, 2024. That code adopts the 2021 International Building Code (IBC), which in turn references American Society of Civil Engineers (ASCE), Minimum Design Loads for Buildings and Other Structures (7-16). The ASCE 7-16 mean recurrence interval (MRI) 25, 50 and 100-year wind speeds for the Project Area are 80, 85, and 92 miles per hour (mph). The final design for this Facility is expected to be completed in accordance with the 2024 Ohio Building Code.
ASCE 7-16 lists wind speed design standards for different types of structures based on risk level (Categories I to IV). To date utility-scale solar facilities have been considered Risk Category I structures, which has a maximum design wind speed of 100 mph We understand that the International Code Council, which develops the IBC, has recently approved and adopted a proposal from the Solar Energy Industries Association to define the Risk Category for groundmounted solar panels to be Risk Category II. While not specifically adopted in the 2024 Ohio Building Code, section 1604.5.2 of the 2024 IBC “Photovoltaics Panel Systems” states “Groundmounted PV panel systems other than those described in Items 1 and 5 shall be assigned to Risk Category II.” It should be noted that neither Items 1 nor 5 apply to this Facility. While the 2024 IBC has not been adopted by the State of Ohio yet, the logic used to apply Risk Category II for these structures remains valid. It is conservative in that it produces a higher load than previously prescribed by the applicable ASCE 7-16 while balancing the importance of large-scale solar panels systems in providing power to the grid. We recommend that the facility be classified as ASCE 7-16 Risk Category II, which has a maximum design wind speed of 108 mph.
The structural design is expected and recommended to include all components of the Facility including solar panels, solar panel mounting systems, rack design, and steel pile design. The
steel pile design should include resistance to wind uplift, downward loading, and lateral loading. Project-specific meteorological stations should be used to monitor local wind speed.
Average hourly wind speed is presented in Table 1, based upon data collected from the Ohio State University College of Food, Agriculture, and Environmental Sciences (CFAES) Weather System’s nearest location which is the Columbus station in Columbus, Ohio (located approximately 32 miles from the Project Area) over a period from April 2022 to March 2025
TABLE 1
Notes:
Source: National Oceanic and Atmospheric Administration (NOAA) National Weather Service Wind Threat Description
Non-Threatening
Very Low
Low
No discernable threat to life and property from High Wind. The sustained wind speeds are non-threatening; breezy conditions may still be present.
A very low threat to life and property from High Wind. Breezy to windy conditions. Sustained wind speeds around 20 mph, or frequent gusts of 25 to 30 mph.
A low threat to life and property from High Wind. Windy conditions. Sustained winds of 21 to 25 mph, or frequent gusts of 30 to 35 mph.
Moderate (sustained speeds of 26 to 39 mph) would be consistent with a Wind Advisory and High (sustained winds of 40 to 57 mph) and greater winds would be consistent with a High Wind Warning.
The Project’s components generally are not susceptible to damage from high winds. The piles for the racking are expected to be made of galvanized steel and will be installed, based on the sitespecific soil conditions, at sufficient depths to prevent the movement of the associated equipment from wind. The racking and solar panels selected during final engineering and design of the Project are expected to be accompanied by wind ratings from the manufacturers.
Based on the history of low probabilities of high wind speeds shown in Table 1 and the recommendation to design the facility to the ASCE 7-16 standard and IBC 2021, it is not necessary to mitigate any adverse consequences.
Respectfully, VERDANTAS
Mark J. Bonifas, PE, LEED AP Senior Consultant, Renewable Energy