ROCHELLE — At its Dec. 11 meeting, the Rochelle City Council approved an engineering agreement with Keith Engineering Design for $115,070 for an expansion of the solar plant at the Rochelle Municipal Utilities wastewater treatment plant.

The solar plant was originally constructed in 2014 at a cost of around $1 million with a $500,000 grant and was designed with the ability to double the existing footprint. Part of the design process for the second half will include pursuing grant opportunities to offset capital costs. 

RMU Superintendent of Water/Water Reclamation Adam Lanning the most recent cost estimate he saw for construction of the new portion was about $1.5 million for construction. He said there are “quite a few” incentives and grant opportunities for solar projects through the state.

“We haven't gotten into searching for grants yet,” Lanning said. “Before construction ever gets approved, we'll demonstrate to the council on how long it will take for the solar panels to pay back the cost of the project through power savings.” 

City Manager Jeff Fiegenschuh has a desire for the city to shave the amount of power that RMU has to purchase off the market, which additional solar panels will help with. The wastewater treatment plant solar field currently has about a one-acre footprint. The solar field currently saves RMU about $30,000 per year in power costs. 

“It's been essentially maintenance free,” Lanning said, “I think we've had to replace three or four inverters since I've been here that were under warranty. We haven't had much snow over the past few years so that hasn't been an issue. Snow cover will block the production of them. I've been pretty happy with it. The numbers have been adding up to what it was designed for. They're doing what they were meant to do.”

Design work and grant applications for the solar expansion will take place in 2024. Lanning said construction most likely will start until 2025 due to components for it being at least a year away from delivery. Once construction starts, the work would take 3-5 months. Completion is slated for before the end of 2025. 

Following the expansion’s construction, the solar panels will be able to cover the wastewater treatment plant’s peak power demand. 

“The wastewater treatment plant peaks at about 600 kilowatts,” Lanning said. “With the current 180 kilowatts and the new panels being twice as efficient with the same footprint, it's going to be close to on average shaving off the peak demand of the wastewater treatment plant, which is typically half of the bill. It could shave a lot of dollars and cents off of the bill.”

Fiegenschuh said the city wants to increase its renewable energy portfolio. The city and RMU have discussed a community solar project where businesses and residents could buy into a solar panel field to help pay to fund it in exchange for a credit or special rate on their RMU bills. 

Other potential solar panels in the city in the future could be at city-owned facilities such as its new building at 1030 S. 7th St. or at City Hall. 

“Any future facilities work, we should be looking at having some solar component to help shed some of that load,” Fiegenschuh said. “But it's not always sunny, so we still have to maintain our distribution system and not everybody can be completely off the grid with renewables. We still need a good source of base load generation to power the city. I think we need to incorporate more renewables and we've seen more applications for residential solar, which we allow on our system now. We've had some conversations with some of our large-scale commercial and industrial customers about solar and shedding some of their load. We've had lots of conversations about solar and we'll continue to do so.”