Piling for Solar Farms

Energy transition projects have rapidly multiplied in the United States because of the on-going push for decarbonization. A large number of these projects involve electric power generation using photovoltaic (solar) panel arrays, popularly known as solar farms. These projects require the installation of pile-supported solar panel arrays and depending on the planned electric power output the number of required piles could be in the six-figure range. A recent prospect aims to install solar panel arrays to generate 6 Gigawatts of electric power, which will require millions of piles. Because the installation cost of piles tends to represent a significant percent of the total project installed cost, pile design and installation time must be optimized for cost effectiveness. Consequently, viable sites need to present favorable subsurface conditions to allow for the use piles that consist of small size steel W-sections pushed/vibrated to depths of around 3 m. Pile design is generally governed by lateral loading caused by wind or earthquakes. Compressive loads tend to be small and tension loads caused by wind can impact pile design. The presence of frost ad-freeze and/or swelling soils can also impact the uplift pile design requiring additional pile length. Near surface rock can require predrilling with major impacts to cost and schedule. Another important consideration at some sites is corrosion protection. The presence of salt flats at a prospective site required the consideration of alternative fiber reinforced pipe piles. The proposed manuscript will present and discuss pile design, testing and production installation at solar farms under construction or recently completed in the United States.