A modeling framework for medium to long-term energy system planning, energy policy analysis, and scenario development

MESSAGEix stands at the core of the Energy, Climate, and Environment program modeling framework.

It provides a flexible framework for the comprehensive assessment of major energy challenges and has been applied extensively for the development of energy scenarios and the identification of socioeconomic and technological response strategies to these challenges.


The modeling framework and the results provide core inputs for major international assessments and scenarios studies, such as the Intergovernmental Panel of Climate Change (IPCC), the World Energy Council (WEC), the German Advisory Council on Global Change (WBGU), the European Commission, and most recently the Global Energy Assessment (GEA)

Scenario analysis with MESSAGEix is used in two major areas:

  1. Description of future uncertainties.
  2. The development of robust technology strategies and related investment portfolios to meet a range of user-specified policy objectives.

Fast Facts

  • MESSAGEix is used in applied projects and scientific studies around the world.
  • Scenarios developed with MESSAGEix have been used in, for example, the assessments and special reports of the IPCC and the GEA.
  • MESSAGEix was used to generate one of the four Representative Concentration Pathways (RCPs) currently being used to estimate future climate change in the context of the IPCC 5th Assessment Report.
  • A special agreement between IIASA and the International Atomic Energy Agency (IAEA) allows MESSAGEix to be used for country studies within the IAEA and its Member States.

gas pipeline © Sergei Ryjkov | Dreamstime.com

How MESSAGEix works

Typical scenario outputs provide information on the utilization of domestic resources, energy imports, and exports and trade-related monetary flows, investment requirements, the types of production or conversion technologies selected (technology substitution), pollutant emissions (traditional indoor and outdoor air pollutants as well as greenhouse gases), and inter-fuel substitution processes, as well as temporal trajectories for primary, secondary, final, and useful energy.

MESSAGEix is also increasingly used for detailed analysis of energy demand issue, such as for policy analysis of energy access in the residential sector.

To address major global challenges in a holistic way, integration of sectoral models is a key issue. Traditionally separated tools for energy supply, demand and end-use analysis, as well as “top down” and “bottom up” analytical representations, have increasingly been either formally integrated or linked with MESSAGEix in an ensemble model integration to assess important interrelations and feedbacks.

MESSAGEix updates, documentation and downloads are available on the MESSAGEix webpage.

Some key uses for MESSAGEix

MESSAGEix is used in conjunction with MAGICC (Model for Greenhouse gas Induced Climate Change) for calculating internally consistent (probabilistic) scenarios for climate change.

Through linkages with the MACRO model economic feedbacks on energy demand are assessed, and further linkages with the GLOBIOM land-use model allows the assessment of land, forest, and water implications of energy systems.

An explicit linkage to the GAINS air pollution framework allows the assessment of health impacts of energy systems.