The MESSAGE (Model for Energy Supply Strategy Alternatives and their General Environmental Impact) integrated assessment model (IAM) is a hybrid model that combines a linear programming (LP) energy engineering model with an aggregated macro-economic model (MACRO) which is solved by using a non-linear program (NLP). At its core is a global systems engineering optimization model used for medium- to long-term energy system planning, energy policy analysis, and scenario development (Messner and Strubegger, 1995). The model provides a framework for representing an energy system with all its interdependencies from resource extraction, imports and exports, conversion, transport, and distribution, to the provision of energy end-use services such as light, space conditioning, industrial production processes, and transportation. In addition, MESSAGE V.4 relies on input from the DIMA forestry model to assess the sink enhancement potential from avoided deforestation and afforestation and bioenergy supply curves from IMAGE.
The framework covers all greenhouse gas (GHG)-emitting sectors, including agriculture, forestry, energy, and industrial sources for a full basket of greenhouse gases and other radiatively active gases — CO2 ,CH4 ,N2O ,NOx, volatile organic compounds (VOCs), CO, SO2, BC/OC, CF4, C2F6, HFC125, HFC134a, HFC143a, HFC227ea, HFC245ca and SF6. MESSAGE is used in conjunction with MAGICC (Model for Greenhouse gas Induced Climate Change) version 5.3 for calculating internally consistent scenarios for atmospheric concentrations, radiative forcing, annual-mean global surface air temperature and global-mean sea level implications.
MESSAGE is designed to formulate and evaluate alternative energy supply strategies consonant with the user-defined constraints such as limits on new investment, fuel availability and trade, environmental regulations and market penetration rates for new technologies. Environmental aspects can be analysed by accounting, and if necessary limiting, the amounts of pollutants emitted by various technologies at various steps in energy supplies. This helps to evaluate the impact of environmental regulations on energy system development.
MESSAGE's principal results comprise, among others, estimates of technology-specific multi-sector response strategies for specific climate stabilization targets. By doing so, the model identifies the least-cost portfolio of mitigation technologies. The choice of the individual mitigation options across gases and sectors is driven by the relative economics of the abatement measures, assuming full temporal and spatial flexibility (i.e., emissions-reduction measures are assumed to occur when and where they are cheapest to implement).