University of Iowa increases biofuel acres with miscanthus

The tall grasses that billow and bend in the wind between Melrose Avenue and the Finkbine Commuter parking lot on Iowa City’s west side not only are beautiful, but they help the University of Iowa toward its goal of going coal free by 2025.

Since 2015, the University of Iowa steadily has increased the acres of giant miscanthus, a perennial grass that can grow up to 12 feet high. From the first commercial plot of 360 acres, the UI now contracts with Greensboro, N.C.-based AGgrowTech to grow 1,100 acres around Eastern Iowa.

“We knew early on growing a local fuel like miscanthus would not only help us reach our goal but would provide many environmental and local benefits as well,” said Wendy Moorhead, UI assistant director of Facilities Management.

“But at that time there was very little commercial miscanthus production in the USA and none in Iowa. We wanted to first make sure it would grow well and we could harvest and deliver. Our current acres have allowed us to better understand the production and provided us with a pathway moving forward.”

During the COVID-19 pandemic, the UI quietly surpassed its goal of having 40 percent renewable energy by 2020. The university now has at least 42 percent of its power from renewable sources and one boiler exclusively fed biomass fuels.

The next goal is going coal free by 2025, a target former UI President Bruce Harreld set in 2017.

Experimenting, learning

Giant miscanthus is widely used for animal bedding, heat and electricity generation in Europe, Japan and China.

It’s one of the most productive biofuel crops in cooler parts of the world, can grow in marginal soil and produces twice the biomass of switch grass, according to a 2019 report sponsored in part by the U.S. Department of Agriculture.

In 2015, the UI predicted it would be growing 2,500 acres of miscanthus by 2020. The university partners with Iowa State University to quantify the environmental benefits of miscanthus and maximize crop health and productivity.

Although the actual acres are lower, the UI and AGgrowTech have experimented with different growing and harvest strategies to maximize efficiency, Moorehead said. This past year, a number of fields were left unharvested to determine whether it was more efficient to harvest every other year.

“Initial indications show that this trial was not successful due to the wear a ‘double harvest’ causes to the harvesting equipment,” Moorehead said.

Fuel pellets

How the UI is using the miscanthus grass also has changed.

The dried grass initially was chopped up and combined with coal. But this year, the UI sent its harvested crop to Convergen Energy, a Wisconsin-based company that uses miscanthus as an ingredient in fuel pellets burned at the UI power plant and others in the Midwest.

The bulk of the pellet makeup is renewable, including miscanthus and non-recyclable paper, but there also is some non-recyclable plastic to allow the pellet to work as a boiler fuel, Moorehead said.

“The pellets are an EPA-designated non-waste alternative fuel with reduced emissions over traditional fuels,” she said. “Ultimately, all harvested miscanthus will be incorporated into pellets and used in boilers to provide energy to the UI.”

The UI’s plans to use more biofuels to move toward that zero-coal goal haven’t been derailed by the university’s decision in 2019 to partner with French energy provider Engie and infrastructure investment company Meridiam for 50 years of private operation of its utility system.

The collaborative paid the UI $1.165 billion up front and then the UI pays the new partner a $35 million annual fixed fee, plus the cost of utility expenses, employees, maintenance and upgrades, among other items.

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