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National Energy Modeling System (NEMS) Documentation Archive

Integrating Module - NEMS Documentation

April 12, 2018

Update information

This edition of the Integrating Module of the National Energy Modeling System: Model Documentation 2018 reflects changes made to the integrating module over the past year for the Annual Energy Outlook 2018. These changes include:

  • Updates to the summary descriptions of each NEMS module
  • Reflects the new Natural Gas Market Module (replacing the Natural Gas Transmission and Distribution Module)
  • Updated module listing for each partition when executing NEMS using the partitioned method
  • Module order was updated to show that the International Energy Module runs just before the Oil and Gas Supply Module
  • Updates to the carbon dioxide emissions factor table

Introduction

The National Energy Modeling System (NEMS) is an energy-economy modeling system of U.S. energy markets for the midterm period, extending through 2050, which currently runs on Windows-based personal computers and terminal servers. NEMS projects the production, imports, conversion, consumption, and prices of energy, subject to a variety of assumptions. The assumptions encompass macroeconomic and financial factors, world energy markets, resource availability and costs, behavioral and technological choice criteria, technology characteristics, and demographics. NEMS produces a general equilibrium solution for energy supply and demand in the U.S. energy markets on an annual basis.

Baseline projections from NEMS are published in the U.S. Energy Information Administration’s (EIA) Annual Energy Outlook. NEMS is developed and maintained by EIA’s Office of Energy Analysis to provide projections of domestic energy-economy markets in the long term and perform policy analyses requested by decisionmakers in the White House; U.S. Congress; offices within the Department of Energy, including Program Offices; and other government agencies. NEMS was first used for projections presented in the Annual Energy Outlook 1994.

Scope and organization

Publication of this document is supported by Public Law 93-275, Federal Energy Administration Act of 1974, Section 57(B)(1) (as amended by Public Law 94-385, Energy Conservation and Production Act), which states in part

...that adequate documentation for all statistical and forecast reports prepared...is made available to the public at the time of publication of such reports.

In particular, this report is designed to meet EIA’s model documentation standard 2002-26, established in accordance with these laws.[1]

For documentation purposes, the individual components of NEMS are considered distinct models and documented individually. While the NEMS integrating module is a distinct component of NEMS, the integrating module is not by itself a model. Rather, it is a component of the overall NEMS model and implements specific aspects of the overall modeling methodology that are not documented elsewhere. The documentation is organized accordingly.

Because the Integrating Module controls the solution process for all components of NEMS, Chapter 2 summarizes NEMS as a whole. Readers interested in a more comprehensive summary of NEMS should see The National Energy Modeling System: An Overview 2009, DOE/EIA-0581(2009), October 2009.[2]

Chapter 3 describes the NEMS global data structure, used for inter-module communication, solution initialization and storage, and certain database operations.

Chapter 4, Integrating Module Solution Methodology, provides the mathematical specification for the solution algorithm and describes the convergence techniques used. Chapter 4 also documents other modeling functions of the Integrating Module, including generation of foresight assumptions and carbon dioxide emission policy routines.

A bibliography is contained in Appendix A, and Appendix B describes some of the configuration management and other implementation practices used to coordinate NEMS software development.

Model archival citation

This documentation refers to the NEMS Integrating Module as archived for the Annual Energy Outlook 2014 (AEO2014).

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Notes and sources

[1]See https://www.eia.gov/about/eia_standards.php#standard2015_1

][2See https://www.eia.gov/outlooks/aeo/nems/overview/pdf/0581(2009).pdf