NEMS Models
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NEMS Contacts

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The National Energy Modeling System (NEMS) represents a general equilibrium solution of the interactions between the U.S. energy markets and the economy. The model achieves a supply-and-demand balance in the end-use demand regions, defined as the nine Census Divisions, by solving for the prices of each energy type so that the quantities producers are willing to supply equal the quantities consumers wish to consume. The system reflects market economics, industry structure, and energy policies and regulations that influence market behavior.

Last Model Update:

October 2000

Part of Another Model?

Part of the National Energy Modeling System

Model Interfaces:

NEMS comprises the following modules with model contacts as indicated.

Sponsor:

• Office: Office of Integrated Analysis and Forecasting
• Division: Energy Demand and Integration Division
• Model Contact: Dan Skelly
• Telephone: (202) 586-1722
• E-Mail Address: dskelly@eia.doe.gov

Documentation:

• Energy Information Administration, I ntegrating Module of the National Energy Modeling System: Model Documentation, DOE/EIA-M057 (2001) (Washington, DC, December 2000)
  http://tonto.eia.doe.gov/FTPROOT/modeldoc/m057(2001).pdf
  
• Energy Information Administration, National Energy Modeling System: An Overview 2000, DOE/EIA-0581(2000) (Washington, DC, March 2000)
  http://tonto.eia.doe.gov/FTPROOT/forecasting/05812000.pdf.

Archive Media and Installation Manual(s):

Archived for the reference case published in the Annual Energy Outlook, 2001, DOE/EIA-0383 (2001). The archive contains all of the modules of NEMS as used in the reference case. The archives containing source code, inputs and outputs, is stored at ftp://eia.doe.gov/pub/temp/aeo/aeo2001.exe as a self-extracting zip file. The archive does not contain an executable for NEMS. Preparing an executable requires Compaq Visual Fortran (http://www.compaq.com/fortran/index.html) and the Optimization Modeling Library from Ketron Management Science (http://ketronms.com).

Coverage:

• Geographic: Nine Bureau of Census Divisions. Some component analytical modules represent energy production or conversion at different levels of regional detail
• Time Unit/Frequency: Annual through 2020
• Product(s): Natural gas, electricity, coal, steam coal, metallurgical coal, distillate fuel oil, residual fuel oil, motor gasoline, jet fuel, liquefied petroleum gases, petrochemical feedstocks, kerosene, other petroleum products, methanol, ethanol, nuclear power, hydropower, and other renewable sources
• Economic Sector(s): Residential, commercial, industrial, and transportation end-use consumption; coal supply; oil and gas production and natural gas markets; utility and nonutility capacity, and generation of electricity; oil product pricing.

Modeling Features:

• Model Structure: NEMS provides an equilibrium framework in which the economic forces of supply and demand can be simulated. Its modular structure allows each individual module to be represented in a different fashion if desired.
• Modeling Technique: NEMS is a simulation of the impacts of present and planned energy market conditions upon the supplies of and demands for energy products. Different techniques are applied in different sectors, as appropriate.
• Special Features: The primary design feature of NEMS is its modularity. That is, the model is organized by fuel production — oil, natural gas, coal, and electricity — and by end-use consumption sector. The modularity allows any single module or group of modules to be run independently as a debugging aid or for stand-alone analysis. Furthermore, modularity also allows the flexibility for each sector to be represented in the most appropriate way, highlighting the particular issues important for the sector, including the most appropriate regional structure.

Non-DOE Input Sources:

All data sources are listed under the appropriate modules of NEMS, which are listed in the Model Interfaces section.

DOE Data Input Sources:

All data sources are listed under the appropriate modules of NEMS, which are listed in the Model Interfaces section.

Computing Environment:

• Hardware Used: A multiuser environment is implemented using two networked Compaq Proliant Servers, model 5500R, each with four 550 mhz Pentium III Xeon processors, 2.5 gigabytes RAM, 54 gigabytes hard disk space; supplemented by a distributed computer sharing system using 8 Dell workstations (model Precision 410), each with two 500mhz Pentium III processors, 512 megabyte RAM, and 18 gigabytes hard disk space.
• Operating System: Windows NT 4
• Language/Software Used: Compaq Visual FORTRAN 6.1; Ketron Management Science's Optimization Modeling Library; MKS Toolkit
• Memory Requirement (image size): 305 megabytes
• Storage Requirement: 2 gigabytes
• Estimated Run Time: 2.5-3 hours CPU time for a single run with all modules on. Often, 3 runs are executed in sequence, or "cycled," to improve convergence. Such 3-cycle runs take between 7.5 and 9 hours.