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NEMS - National Energy Modeling System: An Overview

July 9, 2019


The National Energy Modeling System (NEMS) is a computer-based, energy-economy modeling system for the United States. NEMS projects the production, imports, conversion, consumption, and prices of energy, subject to assumptions on macroeconomic and financial factors, world energy markets, resource availability and costs, behavioral and technological choice criteria, cost and performance characteristics of energy technologies, and demographics. NEMS was designed and implemented by the U.S. Energy Information Administration (EIA) of the U.S. Department of Energy (DOE).

The National Energy Modeling System: An Overview 2018 provides an overview of the structure and methodology of NEMS and each of its components. This chapter provides a description of the design and objectives of the system, followed by a chapter on the overall modeling structure and solution algorithm. The remainder of the report summarizes the methodology and scope of the component modules of NEMS. The model descriptions are intended for readers familiar with terminology from economic, operations research, and energy modeling. More detailed model documentation reports for all the NEMS modules are also available from EIA (Appendix Bibliography).

Purpose of NEMS

NEMS is used by EIA to project the impact that energy, economic, environmental, and security factors can have on the U.S. energy system as a result of alternative energy policies and different assumptions about energy markets. The projection period is about 30 years into the future. The projections in the Annual Energy Outlook 2018 (AEO2018) are from the present through 2050. NEMS provides a consistent framework for representing the complex interactions of the U.S. energy system and its response to a wide variety of alternative assumptions and policies or policy initiatives. As an annual model, NEMS can also be used to examine the impact of new energy programs and policies

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