Power equipment company opts for solaR power

Illinois-based power equipmentcompany G&W Electric has completed a microgrid project?"including a 2.4 MW rooftop solar array?"that will reduce energy costs and provide back-up power, at the company�s manufacturing campus.

By Robin Brunet

Microgrids are gaining traction with companies across the U.S. for one simple reason: the growing availability of battery electric storage systems. By storing power from sources that fluctuate such as solar and wind, battery storage allows usage of energy when it benefits the most, whether during peak hour rates or selling the surplus to a utility. 

There is another key to the success of microgrid projects. Kate Cummings, who manages distribution automation for switchgear at Illinois-based G&W Electric, points out that a growing number of industries are working with utilities to enhance grid resilience and integrate renewable energy sources—with a prime example being when her company, a power equipment manufacturer, decided to develop its own microgrid and contacted its local utility, Commonwealth Edison Co. (ComEd). 

“Our goal was to develop a microgrid for our manufacturing campus in Bolingbrook, Illinois that houses two separate buildings,” she says, adding that the project was undertaken because a glitch in G&W Electric’s power system in 2018 caused significant downtime in its molding facility, causing tens of thousands of dollars in lost production, added maintenance, and discarded materials. 

G&W Electric wanted to provide uninterrupted, premium power and shield against the potential havoc of external grid failures. The result, in collaboration with ComEd, was the first microgrid project of its kind for both the utility and manufacturer. 

In addition to collaborating with ComEd, G&W Electric kicked off the project by retaining Continental Electric, an experienced installer of solar and energy storage: they helped with the interconnect process and selecting components. Sizing was then undertaken, based on current loads, their sensitivity to failure, and factoring in growth. 

The solar array capacity was determined at 2.4 MW DC/2MW AC, with storage calculated at 2 megawatts for four hours. 

The next step was to consider the technology options. “We decided we wanted to use bifacial solar panels with TIGO rapid shutdown devices, as well as a flow battery,” Cummings says, referring to LG bifacial panels using SMA string inverters with TIGO rapid shutdown devices. 

The selection of LG was simple: G&W Electric determined in 2019 that it had the best environmental ratings, lifetime specifications, and wattage generation per size. “While we would have liked to have selected a U.S. manufacturer, there weren’t any we could find back then,” Cummings point out. 

Given the sensitivity of G&W Electric’s molding facility, a flywheel was required to provide ride-thru. “We had uninterruptible power supply (UPS) at each of the controls, but they did not prove to be reliable, so we went with a building-wide flywheel for ride-thru while connecting to the flow battery. We selected a flow battery as opposed to lithium-ion for a combination of reasons including environmental, usage, and total lifecycle costs,” Cummings says. Flow batteries are not flammable and 85 to 90 percent recyclable at the end of their life. It is also possible to deep discharge such batteries while retaining 96 percent of their capacity for their 20 to 25 year lifespan.

“They have a much higher initial cost, but given our planned usage, we would otherwise be looking at two to three installs of a lithium-ion battery,” Cummings says. “Flow batteries admittedly take up more installation space, but that was not an issue for us as we had plenty of installation space in our parking lot.” 

	G&W Electric retained Continental Electric, an experienced installer of solar and energy storage, to help with the interconnect process and selecting components. The project has LG bifacial panels, and uses SMA string inverters with TIGO rapid shutdown devices.

The energy storage was comprised of 500 kW blocks feeding into two 1 MW batteries. 

“That way, we can add 1 MW modules as required,” Cummings explains. “The solar farm on building 305 would be comprised of 32 strings, and using a similar methodology this would enable us to add solar to building 245, as long as we could get the interconnect approved. We could add the flywheel or a genset to 305 without disrupting the system setup.” 

Site prep in 2019 was crucial, and when building 305’s roof was replaced it was with a white membrane instead of the previous rock surface. Engineers were retained to inspect the roof from a weight perspective and determined the areas where the panels and inverters could be installed and the areas that were off limits.

“The key consideration was that the membrane of the new roof couldn’t be punctured, so we had to figure out a way to mount the solar array and ultimately opted for a weighted racking system designed and supplied by Montreal-based OpSun,” Cummings says, describing the system’s appearance as a series of cinder block weighted frame work that was designed to withstand 140 miles per hour winds. 

A potentially ruinous outcome involving the energy storage installation was averted due to scrupulous consulting with the Illinois Environmental Protection Agency. Since the fence of G&W Electric’s Bolingbrook facilities borders on neighboring Romeoville, and with the wellhead for Romeoville located ~300 feet from the fence, the company initially planned to locate the energy storage at Building 245 at the 350-foot mark, based on consultation with Romeoville officials.

By storing power from sources that fluctuate such as solar and wind, battery storage allows the use of energy when it benefits the most, whether during peak hour rates or selling the surplus to a utility.

“But in order to be certain this was acceptable, we contacted the Illinois EPA and they confirmed 400 feet as the ‘keep out’ zone, meaning we had to redo the environmental inspection to see what was under the parking lot as well as redesign the pad for the energy storage,” Cummings says. 

As it turned out, the parking lot at 245 was the dumping ground when the industrial park was built. Some of the material was reusable, such as the gravel, and the rest was safe to dispose of. Excavation up to 10 feet deep was required in order to start developing the pad upon which the 550-ton energy storage system could sit.

“On the day of the cement pour, we had a conga line of cement trucks from seven in the morning until five that afternoon, as it had to be done in one pour,” Cummings says, adding that the pad took 28 days to cure. Meanwhile, inside Building 245 a special flat pad had to be created for the 54-ton flywheel that could withstand the torque coming from its 2,800 RPM of operation. 

G&W Electric and Continental Electric surmounted other challenges. “We used a crane to get the material, tools, and a couple of ATVs onto the roof,” Cummings says. 

“Scaffolding was set up for access to the roof, and there were times where the weather required us to not allow anyone up there—however, this didn’t happen often and the crews never fell behind.” 

Containers were shipped over from Europe via boat and placed by crane on site; the electrolyte for the battery was trucked up from chemical processor U.S. Vanadium in Arkansas, 12 totes per truck. “It look-ed like the flatbeds could have fit more, but due to weight restrictions the limit was 12, otherwise special permitting would have been required,” Cummings says.

Crews from CellCube’s Austria office managed the connections between the electrolyte tanks and the containers; they also pumped the electrolyte into the tanks and managed the charging of the tanks so that one tank per container had positively charged electrolyte and the other was negatively charged. 

As for the flywheel, it was shipped from Germany, and due to its weight and the special handling required, Diamond Rigging and Crane was tasked with delivering it to Building 245. 

By June 2022 all the components had been delivered, and the entire microgrid was installed by Thanksgiving. “The actual installation went very smoothly due to meticulous pre-planning,” Cummings says. 

While many companies were responsible for the project’s success, Cummings stresses that ComEd was the key partner throughout, with one example of invaluable collaboration being that its team was on-site in G&W Electric’s labs on a regular basis to understand the microgrid components and how they would communicate with the utility’s equipment. From there, the utility could create prototypes, perform testing and validate its findings before linking the microgrid to the external grid. 

ComEd also created detailed presentations for grid operators, outlining alarm protocols and response procedures. This ensured the operators were well versed in their roles and responsibilities across various scenarios. 

Cummings says, “Clear, effective communication and role definition were paramount to the success of this collaboration. In fact, the importance of clearly communicating the plan, roles and responsibilities of all stakeholders cannot be overstated. Clearly defined roles and responsibilities mitigated confusion and helped team members to execute their assigned duties.” 

Unsurprisingly, Cummings’ advice to other companies seeking to develop their own microgrid energy generation is to “Bring the grid operators into the fold early in the project. Even though they will not be implementing the microgrid itself, they are the ones who see the alarms and need to understand how to effectively work with the utility when issues arise.” 

As of this past August the G&W Electric microgrid was udergoing final testing and was expected to drastically reduce the company’s energy bills by the end of 2024.

Q4 2024