With the flip of a switch, St. Louis chemical distributor Walsh & Associates, Inc. realized a years-in-the-making dream to slash energy costs at its 88,000-sq-ft warehouse. The switch activated the largest solar array ever built in Missouri, generating power from 416 roof-top solar panels. Installed by electricians from the International Brotherhood of Electrical Workers (IBEW) Local One , the solar array is expected to reduce Walsh’s annual energy bill from $36,000 to $1,500.

“This culminates an eight-year effort to make our warehouse more energy efficient,” says Randall Lewis, Walsh director of operations. “We’ve been cutting power consumption over the years by upgrading to more energy-efficient systems. Federal stimulus funding and passage of the Missouri Proposition C Clean Energy Initiative in 2008 spurred additional investment in solar panels to drastically cut our energy costs.”

Walsh estimates the solar installation will pay for itself in five years through a combination of Solar Renewable Energy Credits (SRECs) and credits from Ameren through net metering. Net metering allows entities with renewable energy systems to earn money or credit from utility companies for the energy they produce.

“During fall and other times of the year when air conditioning is not required, the panels can produce more power than our building needs,” says Lewis. “That excess is returned to the grid for Ameren to use, giving us a credit. We estimate that over the anticipated 25-year life span of the solar panels we could realize a return of investment of an additional $500,000 or even more if electrical rates increase. But to achieve that kind of return on our investment, we needed to make sure the panels were installed properly. That’s why we went with an IBEW Local One contractor.”

Each panel contains a Tigo Energy module that allows Walsh to remotely monitor the effectiveness of each panel. “It requires not only a thorough understanding of how inverters convert DC power into AC power, but requires skill to match the amplitude of the AC sine wave that Ameren has on the grid so the net metering can accurately measure power produced and used,” says Mike Meyers, an IBEW Local One electrician who worked on the project. “Without that precision, Walsh can’t optimize its investment in the panels.”

Designed by Straight up Solar, St. Louis, the solar installation was managed by Bell Electrical Contractors using four IBEW Local One electricians. It consists of 32 strings of panels with 13 panels on each string. Each string can produce 480V.The array covers 10,000 sq ft of roof and can produce 130,000kV to 135,000kV annually.

“Renewable energy installations are becoming increasingly complex as businesses seek a greater return on investment,” says Stephen P. Schoemehl, business manager for IBEW Local One. “So we’re keeping pace by emphasizing renewable energy installations at the Electrical Industry Training Center where Local One electricians are trained and upgrade skills.” The training center is operated by the Electrical Connection, a partnership of Local One and the St. Louis Chapter of the National Electrical Contractor’s Association (NECA).