Wind-energy conversion systems used as electric-power sources are exempt from Minnesota's sales tax. Materials used to manufacture, install, construct, repair or replace wind-energy systems also are exempt from the state sales tax. A "wind energy conversion system" (WECS) is defined as any device, such as a wind charger, wind mill or wind turbine, that converts wind energy to a form of usable energy.
In order to claim the exemption, buyers must complete an exemption certificate ([http://www.revenue.state.mn.us/Forms_and_Instructions/st3.pdf MN Dept. of Revenue Form ST3 - Certificate of Exemption]) and supply it to the equipment seller.