Opponents of large solar installations frequently argue that solar farms will take away land that is valuable for food production when farmers decide to stop tilling and instead lease their land to a power company.
A new study released by Clean Wisconsin rebuts those arguments, specifically looking at the tradeoffs involved in converting land where corn is grown for ethanol production to electricity production.
Its key finding is that a solar farm can produce 100 times the energy of a comparably sized field planted with corn for ethanol, after all energy inputs are included. Those inputs include the cost of building and installing solar panels, and growing, harvesting, transportation and processing costs for ethanol.
But it’s not that simple. For example, it’s not that solar farms are always replacing fields where corn is being grown for ethanol, sometimes the fields are fallow. Rather, the study focused on ethanol production because it represents 1 million acres in Wisconsin that already are producing power rather than food, said Paul Mathewson, science program director for Clean Wisconsin.
“We already use farm land in Wisconsin to produce energy, which is growing corn for ethanol. So we just wanted to push back on that messaging that solar panels and solar facilities are always taking food out of production and show that a quarter of the corn that we’re growing in Wisconsin is already going to energy.”
The important takeaway, he said, is that solar farms can produce far more energy on significantly less land and at a lower cost than is produced by growing corn for fuel.
A previous Clean Wisconsin report on the clean energy infrastructure that would be needed to reach the state’s goal of net-zero carbon emission by 2050 estimated that 31 gigawatts of solar production will be needed to meet that goal. About 250,000 acres would be needed to produce that much energy, about one-third of the land currently used to grow corn for ethanol, according to the new report.
John Butterbrodt, a third-generation farmer near Beaver Dam made the decision to lease 196 acres to Alliant Energy for its Beaver Dam Solar Project. Butterbrodt said he’s a shareholder in an ethanol plant in Friesland and continues to support ethanol and growing corn to produce it. But, he said, he, his brother and a neighbor each decided the economics were better to lease land to Alliant for the 350-acre solar farm that is expected to become operational later this year.
Butterbrodt said he “went public locally” to explain his decision and try to offset other residents’ concerns about the loss of agricultural land.
“There’s people who say, ‘Oh, we need that for food production,’ and I point out that, right here in Dodge County, the federal government is paying landowners not to crop their lands,” he said.
One way of measuring the amount of energy that can be produced on an acre of land is to look at the number of miles that internal-combustion and electric vehicles can be driven based on the energy produced on the same number of acres.
The study estimates that Wisconsin’s 1 million acres of corn produces enough energy to power the annual travel of 700,000 internal-combustion passenger cars or 2 million electric vehicles. Solar panels on that acreage could power the annual travel of 60 million electric vehicles, the study states. That’s not even close.
If the ethanol is converted to electricity to power electric vehicles, corn ethanol would require 32 times the amount of land to power the same number of vehicle miles, the study states.
What’s important, Mathewson said, is that the study highlights how little land — about 3% of the state’s agricultural land — would be needed to meet the state’s future solar energy needs.
“A quarter of the corn that we’re growing in Wisconsin is already going to energy, and when you compare the energy efficiencies of the two, we could be producing much more energy on the same amount of land,” he said.
