Johnson County triples its solar power production

Johnson County is installing two new solar arrays at its Iowa City campus in a move that officials say will save taxpayers money and triple the county government's production of clean energy.

One array will be built next to the county's administration building on South Dubuque Street on the site of the former Johnson County Armory, which was torn down following flooding in 2008, and another has already been added to the roof of the county's Health and Human Services building across the street at 855 S. Dubuque St.

Together, the 85-kilowatt ground array and 159-kilowatt rooftop array will produce about 308,000 kilowatt-hours of electricity a year, or roughly the equivalent of taking 46 cars off the road for a year, according to Johnson County Sustainability Coordinator Becky Soglin.

"One-quarter of the electrical use by the administration building will be this clean, solar-generated energy," Soglin said. "And for the Health and Human Services building, that rooftop array is expected to provide about 11 percent of the electrical energy needs of that building."

Last year, two smaller arrays went live at the county's secondary roads department at 4810 Melrose Ave., producing about 116,000 kWh of electricity a year.

The new arrays are financed through power purchase agreements, meaning the county pays a third party — in this case, Dubuque-based Eagle Point Solar — a lower rate for the electricity while Eagle Point takes advantage of government tax credits for renewable energy and provides maintenance of the solar panels. The county's 20-year contract with Eagle Point will cost a total of $274,000 for the ground array and $473,000 for the rooftop array, Soglin said. If it chooses, the county could end the contracts five or 10 years early to cut costs, but it would mean assuming upkeep responsibilities for the arrays.

Supervisor Mike Carberry said Johnson County is committed to continuing to expand its use of clean energy.

"We’ll look to continue to move forward and use solar and wind where it’s site-appropriate as much as we can, and this saves the taxpayer money," Carberry said. "It’s actually really beneficial for us to do this to lower our own utility bill, and if the laws of the state and Iowa Code allows it then we’re going to take advantage."

Carberry envisions the eventual creation of larger solar farms, perhaps at the Johnson County Poor Farm, that could produce more electricity than the facility uses and sell the excess electricity back to the utility to offset the cost. A new ruling from the Iowa Utilities Board will make that easier in the future, he said, but the current projects were designed not to overproduce.

One location where Johnson County definitely intends to install more solar is on the roof of the new ambulance and medical examiner building, which is scheduled to open next year after construction is completed. Other options would be county buildings like the courthouse and jail, Carberry said.

In fact, the Johnson County Jail is no stranger to solar power — panels were placed on the building's roof in 1981 before eventually being taken down, Soglin said. Those panels operated differently than modern panels, providing heat for ventilation and hot water rather than electricity for the building.

Soglin said it's also important to pair the county's investment in solar with efforts to improve building efficiency so less energy is needed overall. She said the administration and Health and Human Services buildings have gone through heating and cooling projects to work more efficiently, and the light bulbs in the administration building have been replaced with LEDs that use less energy.

"Just because you can get it from the sun doesn’t mean you should not be doing these energy efficiencies," she said.

The array near the administration building also provides an opportunity for Johnson County to mitigate stormwater runoff and improve soil quality, said Kate Giannini, a county soil and water conservation specialist.

The soil where the old armory stood is compacted and poor in quality, Giannini said, so it doesn't absorb as much rainwater as healthy soil. That leads to excess nutrients running off into nearby Ralston Creek and eventually into the Iowa River.

"We want those soils to essentially act like a sponge and soak up that rain so that we have less runoff going into our local streams," Giannini said.

To reduce runoff, Johnson County has hired Quality Care, a Coralville-based landscaping company, to carry out a soil quality restoration project by bringing in truckloads of compost that will be spread over the site and tilled into the existing soil. Work on that portion of the project will be completed before the solar panels are installed.

When the panels are in place, the county will plant a low-maintenance grass in the soil and put up a fence around the project for people's safety.

Carberry said the soil restoration portion of the project shows the county's commitment to all forms of sustainability, not just in energy production.

"We could have just put rocks under there, but we have a lot of stormwater issues in this area where the administration building is and if we put just gravel or rocks under there we probably wouldn’t have been able to mitigate stormwater," Carberry said.

Reach Stephen Gruber-Miller at 319-887-5407 or sgrubermil@press-citizen.com. Follow him at @sgrubermiller.