MESSAGE (Model for Energy Supply Strategy Alternatives and their General Environmental Impact) has been developed by the International Institute for Applied Systems Analysis (IIASA) in Austria since the 1980s [1, 2]. Depending on the scope and research question, various different versions of the model have been created with several hundred users. MESSAGE is free for use for academic purposes only. A special agreement between IIASA and IAEA permits its use within the IAEA and its member states. The latter has facilitated a number of in-depth national modelling studies and modelling training courses for energy experts of the IAEA member countries: usually taking approximately 2 weeks of training to be able complete basic applications.
MESSAGE is a systems engineering optimization model used for the planning medium to long-term energy systems, analysing climate change policies, and developing scenario, for national or global regions. The model uses a 5 or 10 year time-step to simulate a maximum of 120 years. All thermal generation, renewable, storage and conversion, and transport technologies can be simulated by MESSAGE as well as carbon sequestration. Inputs for the model are very detailed on the supply side but the demand inputs are more aggregated. The model’s principal results are the estimation of global and regional, multi-sector mitigation strategies instead of climate targets. MESSAGE allows determining cost-effective portfolios of GHG emission limitation and reduction measures. It has recently been extended to cover the full suite of GHGs and other radiative substances for the development of multi-gas scenarios that aim at stabilising future CO2-equivalent concentrations . The model stands at the heart of the IIASA Integrated Assessment Framework, including soft- and hard-links to other spatial and regional modelling tools. Together the IIASA modelling framework represents the global economy and its main sectors (energy, agriculture, forestry) through dedicated macroeconomic equilibrium as well as system engineering modelling tools .
MESSAGE has previously been used to develop global energy transition pathways together with the World Energy Council  and GHG emission scenarios for the Intergovernmental Panel on Climate Change . The model’s most recent scenario assessment with focus on climate stabilization is summarized in 8 papers of the Special Issue of Technological Forecasting and Social Change [4, 7]. Recent national studies with MESSAGE have for example focused on evaluating the impact of innovation programs on the Iranian electricity sector , assessing policy options for increasing the use of renewable energy , analysing energy supply options and security of energy supply in the Baltic states  and designing a sustainable energy plan for Cuba . Finally, the global MESSAGE model has been used to simulate high renewable-energy penetration in the GGI B1 scenario of up to 70% for the electricity sector, 60% for the heat sector , and 55% for the transport sector , with the quantitative data available at .
- Energy Modeling Framework: Model for Energy Supply Strategy Alternatives and their General Environmental Impact (MESSAGE), International Institute for Applied Systems Analysis 26th April 2009, http://www.iiasa.ac.at/Research/ENE/model/message.html
- Messner, S. & Strubegger, M. User’s Guide for MESSAGE III. International Institute for Applied Systems Analysis, 1995, http://www.iiasa.ac.at/Admin/PUB/Documents/WP-95-069.pdf.
- Rao, S. & Riahi, K., The Role of Non-CO2 Greenhouse Gases in Climate Change Mitigation: Long-term Scenarios for the 21st Century. Energy Journal, 27(Multi-Greenhouse Gas Mitigation), pp. 177-200, 2006.
- Riahi, K., Grübler, A. & Nakicenovic, N., Scenarios of long-term socio-economic and environmental development under climate stabilization. Technological Forecasting and Social Change, 74(7), pp. 887-935, 2007.
- Nakicenovic, N., Gruebler, A. & McDonald, A., eds. Global Energy Perspectives. 1998, Cambridge University Press: Cambridge.
- Nakicenovic, N., Alcamo, J., Davis, G., de Vries, B., Fenhann, J., Gaffin, S., Gregory, K., Grübler, A., Jung, T. Y., Kram, T., La Rovere, E. L., Michaelis, L., Mori, S., Morita, T., Pepper, W., Pitcher, H., Price, L., Riahi, K., Roehrl, A., Rogner, H. H., Sankovski, A., Schlesinger, M., Shukla, P., Smith, S., Swart, R., van Rooijen, S., Victor, N. & Dadi, Z. Special Report on Emissions Scenarios. Intergovernmental Panel on Climate Change, 2000, http://www.grida.no/publications/other/ipcc_sr/.
- Grübler, A., Nakicenovic, N., Riahi, K., Wagner, F., Fischer, G., Keppo, I., Obersteiner, M., O’Neill, B., Rao, S. & Tubiello, F., Integrated assessment of uncertainties in greenhouse gas emissions and their mitigation: Introduction and overview. Technological Forecasting and Social Change, 74(7), pp. 873-886, 2007.
- Shafiei, E., Saboohi, Y. & Ghofrani, M. B., Impact of innovation programs on development of energy system: Case of Iranian electricity-supply system. Energy Policy, 37(6), pp. 2221-2230, 2009.
- Assessing policy options for increasing the use of renewable energy for sustainable development: Modelling energy scenarios for Sichuan, China., International Atomic Energy Agency, 2007, http://www.iaea.org/OurWork/ST/NE/Pess/assets/sichuan_case_study.pdf.
- Analyses of Energy Supply Options and Security of Energy Supply in the Baltic States., International Atomic Energy Agency, 2007, http://www.iaea.org/OurWork/ST/NE/Pess/assets/TE_1541_balticstudyFeb07.pdf.
- Cuba: A Country Profile on Sustainable Energy Development., International Atomic Energy Agency, 2008, http://www-pub.iaea.org/MTCD/publications/PDF/Pub1328_web.pdf.
- Greenhouse Gas Initiative: Scenario Data Base, International Institute for Applied System Analysis (IIASA), 12th June 2009, http://www.iiasa.ac.at/Research/GGI/DB/