The suit claims some farmers paid as much as $500,000 for wind turbines that were defective, and that weren't eligible for federal stimulus grants as promised.
Swanson's office said at least 15 Minnesotans have been affected.
The wind company, Renewable Energy SD, is reportedly chartered in South Dakota, and its owner, Shawn Dooling, 46, is from Shorewood, the Star Tribune reports.
The lawsuit claims Dooling told farmers that the windmills would produce excess energy that could sold to the power grid and that the devices would pay for themselves in 5-10 years.
However, the lawsuit claims, Dooling continued to break promises, and delivered the units late, if at all. Many of the turbines, the lawsuit claims, failed to work.
According to the lawsuit, Dooling has personally enriched himself at farmers' expense, and has built $1 million collection of expensive cars in the past several years.