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Creating a Win-Win with Solar Energy


Thelen Sand & Gravel Invests in Solar Power at Its Antioch, Ill., Operation, Freeing up the Local Energy Grid for Its Neighbors and Reducing Its Environmental Impact.

By Therese Dunphy

Ensuring the highest and best use of their land drives many of the decisions the Thelen family makes about the company’s various sites. “Our family is really a steward of the land,” explained Steve Thelen, president of Thelen Sand & Gravel. “Our father instilled in us that you never waste your land. You can use your land to make a living, but don’t contaminate it.”

One Site, Many Uses

A portion of the company’s operation in Antioch, Ill., was mined until the 1960s, then used as a certified clean construction demolition and debris site. More recently, the parcel was host to the operation’s aggregate stockpiles. Last year, however, the 7.5-acre tract was repurposed as the site of the state’s largest behind-the-meter solar installation with a total of 7,260 panels.

Construction of the project began last July, and the system was put into service in September. It was the result of nearly three years of research and the utilization of federal and state incentives. A federal investment tax credit provided a 30% discount, while additional incentives from the state and local power provider enabled Thelen to greenlight the project.

“We chose solar because the incentives from Illinois created an environment where we could efficiently generate our own power and provide our own power needs which would create a sustainable future for our mining operations,” Thelen said. 

The producer worked with SunPeak, which has extensive experience in developing and installing commercial solar systems. “The payback is incredibly quick,” Thelen said. “We potentially could have our investment repaid within 24 months.”

Tying into Sustainability

During the estimated 30-year lifespan of the project, it is expected to generate 72 GWh of electricity, reduce carbon dioxide emissions by 54,900 tons, and reduce landfill waste by 17,800 tons.

On a day-to-day basis, the solar project supplies about 30% of the operation’s needs, but at the peak sunny day, it can generate up to 70% of the operation’s power needs. This timing is particularly important because the Antioch operation is at the end of its power supplier’s line, meaning that it could experience voltage fluctuations when demand is high.

“Our provider has upgraded its system over a number of years, but they had many, many times when they asked us to curtail our consumption so they could provide residents with power,” Thelen explained. “Now, on a beautiful sunny day, I’ve taken 70% of my load off the system, which is similar to being curtailed, while everyone still has their air conditioner on.”

Importantly, the operation can run efficiently and not worry about shrinking energy consumption during its permitted hours of operation, which coincide with peak power loads during hot weather. “It gives me the opportunity to continue my operations and I don’t necessarily believe that I’ll run into these curtailment issues in the future,” he said.

Garnering Recognition

In 2019, Thelen Sand & Gravel won the Illinois Association of Aggregate Producers (IAAP) inaugural Sustainability Award, which is designed to recognize companies that implement solutions to increase efficiency, and/or reduce energy demands and negative environmental impact, and improve employee and community satisfaction. “I was actually surprised by it,” Thelen said. “It was a high honor for me.” Personally, Thelen also received the group’s Industry Leadership Award.

Thelen had hoped to hold an open house to invite the community, state legislators, and others to the site, but installation was completed just as the busy fall season began. By spring, the coronavirus put a halt to public gatherings, but Thelen says he still anticipates hosting such an event when the time is right.

In the meantime, despite nearly 40 years of reserves, Thelen is already looking ahead to the next use of the land and has plans to convert it into an industrial park. “As I would then move to the next use, that same solar system will provide a lot of what the industrial park would need,” he said. “We’re really looking forward to the next generation’s success, not necessarily my success or my generation’s success.”


Therese Dunphy has covered the aggregates industry for nearly 30 years, while also serving multiple roles as a public official. As the owner of Stone Age Communications, she provides communications consulting services to help aggregate producers build stronger relationships within the communities they serve. She can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it..