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Gravel pit solar farm powers Chicago area firm

Germany’s Schletter Group drove deep in supplying the mounting systems for a new solar project in a gravel pit near Chicago.

Schletter secured 7,260 solar modules for a 2-MW project helping power the Thelen Sand & Gravel business. Wisconsin-based SunPeak developed the gravel pit solar farm.

The stone-riddled and compact ground forced some changes to the work plan.

“The plant for Thelen Sand and Gravel was not one of these large off-the-shelf projects,” said Fabian Huber, head of technical advisory for ground-mounted systems at Schletter. “Our tests showed that the pile-driving profiles we normally use with a material thickness of three millimeters (mm) were not strong enough to be reliably inserted into the ground.”

In order to solve this problem and ensure safety, extra-strong pile foundations with a material thickness of 4 mm were used, as well as preventative profile geometry. Although systems with only one support are commonly used for ground-mounted installations in the U.S., this project used a two-support structure.

“For this situation, a two-support structure was the more economical solution,” Huber added. “The benefit of additional stability clearly outweighs the slightly higher costs of material.”

Schletter Group and SunPeak have partnered together for many years, contributing a total of over 20 MW in projects. Thelen commissioned it in hopes of saving on energy costs and lowering its carbon footprint.