Solar Power World

Schletter provided a stronger racking and mounting system when weak soils endangered a California project.

Wolfgang Fritz, vice president of engineering for Schletter Inc., says the company discovered a problem on a 15 mW project in Five Points, Calif., when it sent an engineering team to examine the subsurface on which the project was scheduled to be built.

“The problem was that once we went 4 to 8 ft down where we were going to have to put the posts for our racking system, we discovered the soil wasn’t strong enough to hold our systems in the wind prone outside areas,” Fritz says. “We had to find a solution to the problem quickly.”

There were two possible solutions: Put in more posts to hold the load, or put concrete foundations around the posts to provide more support. After consulting with Pacific Gas & Electric and Solon, they decided to go with the concrete foundations.

“Our engineering team got right on the project and designed a custom-made racking system that took into account the concrete,” Fritz says. “We also had to add a cathodic protection system on the rack to make sure the driven posts didn’t corrode prematurely. It was a particular challenge, but our team rose to it.”

It took a significant increase in the number of workers (nearly 200 working three shifts) and a few months for Schletter to complete the project, but in the end everything worked out well.

“The outcome was that they installed the system as it should be,” Fritz says. “Solon was happy, their client was happy and it all turned out great in the end.” SPW

Schletter Inc. :

Type: Ground-Mount PV

Size: 15 mW

Project Location: Five Points, Calif.

Partners: Solon (project manager); Pacific Gas & Electric (client)