
NEMS is a model of U.S. energy economy developed and maintained by the 
US Energy Information Administration (EIA) of the US Department of Energy (DOE). 
NEMS is used to produce the Annual Energy Outlook, a reference publication 
that provides detailed forecasts of the energy economy from the current 
year to 2040.  DOE first developed NEMS in the 1980s, and the model has 
undergone frequent updates and expansion since.  DOE uses the modeling 
system extensively to produce issue reports, legislative analyses, and
respond to Congressional inquiries.  

US EPA docketed two 2015 National Energy Modeling System (NEMS) files 
that EPA modified in order to use NEMS to estimate the national energy system
impacts of the Final New Source Performance Standards.  
 
These codes are part of the larger set of source codes and input files that constitute NEMS.  
Interested parties should contact the US Energy Information for more information 
on NEMS or obtaining the complete source code.

The files are:

1. wellcost_docket.txt (source file for the Oil and Gas Supply Module)
2. ngitm_docket.f (source of the Natural Gas Transmission and Distribution Module) 

For more detail, the reader should consult Section 6 of the Regulatory Impact 
Analysis which is also available in the Docket. This section explains how the
final NSPS was implemented within NEMS.