Officials are looking to install 9,300 panels on the roofs of buildings at the Noblesville facility.
Critics contend the measure is part of a broader nationwide push by utilities to seize control of the emerging solar market.
The controversy surrounding solar power legislation, the sentencing of the man charged with murdering Shaylyn Ammerman and the Louisville toll bridge.
A bill headed to the House would change the way alternative forms of energy, such as solar power, are valued in the state.
At least one lawmaker says he voted for Sen. Brandt Hershman's measure in committee based partly on the inaccurate information.
Critics say the measure would muscle out smaller competitors from the emerging solar market.
The 21,000 panel solar farm will go on a portion of a former Continental Steel plant.
If approved, it would be Duke's largest solar facility in Indiana.
It will feature 76,000 solar panels on roughly 145 acres of land owned by NSA Crane, making it one of the largest solar facilities in Indiana.
Indiana kept with national trends over the last few years, as only two wind farms have been developed in the Hoosier state over the last four years.