Subtract one pound of steel per foot length from every pile used to support a solar photovoltaic panel, and you may save millions of pounds — and a lot of money. The idea, which involves changing the way photovoltaic ground mount piles are designed, came from a partnership between HDR structural engineer Steve Gartner and PACO Steel, and has earned recognition in the American Society for Civil Engineering Innovation Contest, taking home the Feasibility Award in the Innovative Business Model category.
The new design process involves using a fully automated electric resistance forge-welded process that lets engineers design custom-made piles with very little excess steel. Previously, the steel piles used for the ground mounts were designed by choosing from six standard hot-rolled sections in the American Institute of Steel Construction manual. Now, there are more than 2,000 options to choose from that meet project load demands and result in very little excess steel. The process is flexible enough to accommodate both PV tracker and PV fixed-tilt systems.
The process has been proven effective on multiple pilot projects and studies. Steel weight savings on the projects ranged from 10 to 25 percent compared to the weight of standard hot-rolled steel pile sections. Photovoltaic facilities average 500 steel piles per megawatt, and projects with more than 100,000 steel piles are not uncommon. On the five pilot projects, steel tonnage was cut by from more than 200,000 to more than a million pounds.
Working together, the HDR and PACO Steel team pioneered the innovative process, which will allow solar farm owners to reinvest their cost savings into additional photovoltaic panels or other areas of the facility. The process may also make it possible for additional solar projects to move forward because budgetary concerns related to material costs are lessened.
— Solar Builder magazine