Energy.gov

New electricity generating facilities built in Montana with a capacity of up to one megawatt (MW) that use an alternative renewable energy source are exempt from property taxes for five years after operation begins. The taxable value of the property varies depending on the property ownership and class. The assessed value of personal property is adjusted yearly based on a trend factor that reflects the relevant rate of inflation and on the Montana Department of Revenue’s depreciation schedule. State property tax exemption forms are available at the Department of Revenue’s county office.

"Alternative renewable energy source" includes energy sources such as solar energy, wind energy, geothermal energy, conversion of biomass, fuel cells that do not require hydrocarbon fuel, small hydroelectric generators, and methane from solid waste that is used to generate energy in a useful form, including electricity.