EPAUS9R - An Energy Systems Database for use with the Market Allocation (MARKAL) Model

What is the EPAUS9r energy systems database?

The EPAUS9r is a 9-region database representation of the U.S. energy system. The regional breakdown is based on the nine U.S. census divisions. The database was developed by EPA researchers for use with the MARKAL model. MARKAL is an energy system optimization model used by local and federal governments, national and international communities and academia. It helps decision makers understand the complex system interactions related to energy use. MARKAL is used in over 35 countries. The Energy Technology Systems Analysis Programme (ETSAP) of the International Energy Agency oversees its development.

The EPAUS9r is a fully transparent, publicly available database. The unique contribution of this database lies in its thorough representation of greenhouse gas (GHG) and air pollutant emissions. EPA researchers use MARKAL to analyze the environmental impacts of potential changes in the way the U.S. produces and uses energy. EPAUS9r represents energy supply, technology, and demand throughout the major sectors of the U.S. energy system. The sectors include

  • commercial,
  • industrial,
  • residential,
  • transportation, and
  • electricity generation.

Energy resources represented in the database include

  • coal,
  • natural gas,
  • petroleum, and
  • renewable (e.g., wind, solar, biomass, geothermal, and hydropower).

The EPAUS9r has a set of baseline assumptions developed characterizing U.S. energy supplies, demands, and technologies through the year 2055 in 5-year increments at the level of the nine U.S. Census Divisions.

How does the database work?

MARKAL is a least cost optimization model. When run with EPAUS9r, it calculates the least cost set of technologies that satisfy the specified demands over time, subject to user-defined constraints. Outputs of the model include:

  • The technological mix at intervals into the future
  • Total system cost and energy demand (by type and quantity)
  • GHG and air pollutant emissions

What are the benefits of using this energy systems database?

The EPAUS9r can be used within MARKAL to evaluate the effects of alternative future technology scenarios on air pollutant and GHG emission levels. Users can identify cost-effective and environmentally friendly energy strategies for electric power generation, and for meeting the energy demands of industrial processes, the transportation system, and buildings.

Users can customize their future energy scenarios to include reduction targets for carbon dioxide emissions; water availability for electricity generation; and advances in technology.  The analyses of these scenarios can provide decision makers with a better understanding of how a changing energy landscape will affect future air quality and contribute to meeting mitigation targets and adaptation goals.

Who should use the databases?

Universities, non-government organizations, and other governmental agencies use the EPAUS9r in their research.  It is also used extensively by EPA for a variety of analyses.


U.S. EPA (2013) “EPA U.S. Nine-Region MARKAL Database - Database Documentation.” Publication Number 600/R-13/203.

Technical Contact

To obtain information and instructions for access to MARKAL, contact:
Carol Lenox, Environmental Scientist