Spokesperson Jarrod Erpelding said he expects construction at Commerce Park, on Jim Johnson Road off Highway 79 in Clarksville, to last about four years.
He said Tennessee's interest in solar technology attracted them to the Clarksville area.
"Tennessee seems to have done a fantastic job of committing themselves to finding green technologies, specifically solar technology companies," Erpelding said. "They seem to be at the forefront in the United States of doing that, so that's a tremendous amount of hard work and effort by Governor Bredesen and a number of legislators at both the state and local level."
The new plant will bring 500 jobs to Montgomery County initially.
Once production is at full capacity in about four years the company expects to have around 900 employees.
The new facility will make solar grade polycrystalline silicon, an important raw material for solar panels.
Hemlock also produces semiconductor-grade polycrystalline silicon, a material that is used for integrated circuits in cell phones, digital cameras and computers.
The Clarksville Hemlock plant will mean the creation of hundreds of highly specialized jobs and the state is giving local Austin Peay University the means to train future workers.
Tennessee will give APSU $6.4 million to start a whole new curriculum.