Iowa State, Alliant discuss project behind largest DOE agrivoltaic program award

Iowa State University and Alliant Energy expect its solar agrivoltaics project to commercialize fully in early 2024 after construction wrapped up earlier this month.

This is part of the state university’s five-year strategic sustainability plan of eliminating coal, reducing greenhouse gas emissions by 50%, tripling renewable energy, and reducing annual building energy use by 5% from a 2012 baseline — all by 2025.

So far, 48% of total campus energy is renewable — 8% to 10% from wind and solar farms in partnership with the City of Ames, and 40% from renewable energy credits, said ISU’s News Service Director Angie Hunt, based on information from the school’s Office of Sustainability, in an interview with NPM.

This February also marked the end of ISU’s burning of coal, which reduced emissions by 35% and saved USD 2m per year.

The 10-acre, 1.35 MW solar farm is also Alliant Energy’s first customer-hosted array with a total cost of USD 4.2m. Approximately USD 1.8m of the cost is covered by a four-year grant from the US Department of Energy (DOE)— the largest allotment awarded from the agrivoltaics program.

“Our collaboration, the design and the research, combined with the investment by Alliant, and the capital costs this infrastructure made — I think it was a really easy decision for the DOE to make it the largest awarded project in that grant portfolio,” Alliant’s Strategic Partnerships Manager Nick Peterson said.

The project was previously a regular solar farm, so the remaining cost needed to transform it into an agrivoltaics project, required by the grant, came from an investment from Alliant.

The university had been pursuing a public-private partnership (P3) for the updating and operation of its aging campus utility system to keep the school in line with state mandated renewable targets — net zero emissions by 2050. At this time, there are no plans to pursue a P3 agreement for the power plant, but the university is upholding previously set clean energy goals through grants like the agrivoltaics program, added ISU’s Hunt.

Agrivoltaic details

The DOE funding will support the on-site research through three growing seasons. The school’s horticulture, economics, engineering and entomology students and professors will record progress with a controlled group.

“As the strawberries and raspberries come in for early spring, we’ll start to see how those produce and collect data from the inverters,” Peterson said. “By next fall, we should have some pretty good data.”

Different solar panel sizes from 5 ft to 8 ft will change how much light reaches the plants and alters the microclimates under the panels, influencing humidity and temperature. All of the panels are bifacial, collecting energy from both sides, and some rotate to track the sun across the sky.

The university’s entomologists are also raising honeybees and tracking how the bees interact with the habitat.

Harvested crops will go to the ISU Horticulture Research Station, where they will be cleaned, packaged, and sold to the university’s dining halls.

ISU is also required by the grant to reach out to underrepresented farming groups such as refugee and Indigenous communities and give them the opportunity to grow crops around the arrays.

The school’s horticulture department is working with Global Greens, an organization based in Des Moines that resettles refugee farmers.

“Land access is a big problem for specialty crops,” Professor of Horticulture and this project’s Lead Investigator Ajay Nair said. “So, in the future, they might be the growers working under these panels. It's a pretty inclusive project.”

Alliant leases the land from ISU and the energy not utilized by the farm will go back on the grid for Alliant’s customers and the institution’s facilities through utility credits for leasing the land.

*This story was originally published exclusively for NPM subscribers last month.


New Project Media (NPM) is a leading data, intelligence and events company dedicated to providing origination led coverage of the renewable energy market for the development, finance, advisory & corporate community.