In January 2012 (revision March 2012) the Department of Energy National Renewable Energy Laboratory (NREL) released the study report “Navajo Generating Station and Air Visibility Regulations: Alternatives and Impacts.” The purpose of this was to address in one study all information on various the issues affecting NGS for the Environmental Protection Agency to consider in its development of the Best Achievable Retrofit Technology (BART) proposed rule for NGS.

A scoping study on clean energy alternatives, the “Navajo Generating Station and Clean-Energy Alternatives: Options for Renewables,” was published by NREL in June 2012 to lay the groundwork for further research on clean energy alternatives to NGS.