The Energy Technology Systems Analysis Program (ETSAP) is an Implementing Agreement of the International Energy Agency (IEA), first established in 1976. It functions as a consortium of member country teams and invited teams that actively cooperate to establish, maintain, and expand a consistent multi-country energy/economy/environment/engineering (4E) analytical capability. Its backbone consists of individual national teams in nearly 70 countries, and a common, comparable and combinable methodology, mainly based on the MARKAL/TIMES family of models, permitting the compilation of long term energy scenarios and   in-depth national, multi-country, and global energy and environmental analyses.

By statute, ETSAP meets twice a year to exchange experiences, discuss ways to improve the tools and manage the common activities. Local experts are invited to these meetings so that they are exposed to the paradigm and can interact with the ETSAP participants from their country. These meetings are also held in non-Annex I countries and they often lead to collaborative model building projects with local and third party funds.