Foundations for Ground Mounted Solar Installations


Ground-mounted systems are probably the simplest way to install solar on a larger scale compared to other types of installations such as roofs or parking structures. These systems can be held down by a variety of foundations, including concrete footings, pile driven posts, piers, metal earth screws or with ballasted holding trays.

One size fits all?

Foundation systems need to correspond to the existing site considerations and soil static conditions according to engineering calculations and  building codes. The one size fits all approach will not lead to the most cost and resource efficient results. Here are some key factors that will help to determine the foundation type:

  • Tilt angle and tracking characteristics of the solar power system.
  • Local design wind speeds and snow loads (If applicable) where the solar power system is to be installed.
  • Support and racking configuration.
  • Overall solar module system size and weight.
  • Local design codes and project requirements.
  • Soil characteristics relative to friction, sliding, consolidation, slope stability, salinity, etc.
  • Brownfield or landfill

Foundation types 101

The following table provides an overview of aspects to consider when choosing the appropriate foundation for a ground mounted solar array.

Engineered Foundation

Regardless of the type of installation method all solar installations need a stable and secure support system and foundation. The longevity of the investment is determined by the weakest part of the system. Therefore it is essential to provide a quality, engineered foundation which suits the needs of each individual project and application. Choosing the right solar module support system method involves understanding a variety of environmental and soil mechanical factors.

Helge Biernath is the President & CEO of Sunstall, an installation company in California with the main focus on large solar projects. His company consults clients to find optimized racking and foundation solutions.

About Author

Walter’s contributions to CleanTechies over the past 4 years have been instrumental in growing the publications social media channels via his ongoing editorial and data driven strategies. He is the founder and managing director of Sunflower Tax, a renewable energy tax and finance consultancy based in San Diego, California. Active in the San Diego clean technology community, participating in events sponsored by CleanTech San Diego, EcoTopics, and Cleantech Open San Diego, Walter has also been a presenter at numerous California Center for Sustainability (CCSE) programs. He currently serves as an adjunct professor at the University of San Diego School of Law where he teaches a course on energy taxation and policy.


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    Oriental Hornet: Expert Solar Power Harvester

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