Together, Central and South America and the Caribbean represent more than 450 million people and 12% of the Earth's total emerged land. The region stands out in the global energy landscape for the outstanding contribution of renewable sources to its energy production. Maintaining this level of renewable energy in the future might prove a challenging task, as ‘historical' energy sources (hydropower, biomass) run into sustainability issues and ‘new' options (wind, solar, geothermal energy) still depend on public support schemes. However, South America's small fossil resource endowment and excellent renewable potential make it the ideal candidate for pioneering a renewable energy transition. The energy sector's contribution in fueling economic growth in a socially and environmentally sustainable way is also an issue that is particularly significant in the developing context on the continent. Climate change is a region-scale concern. The continent's emissions per capita are above the global average, and the region is also likely to be one of the most impacted by climate change. South America's energy sector is vulnerable both on the supply side (hydropower and biomass resources) and the demand side (increased demand for e.g. agriculture and air conditioning). Despite shared regional strengths and concerns, however, South America appears as a highly heterogeneous and fragmented continent. The region's physical layout is a stumbling block for regional integration. Two centuries of regional wars complicate political cooperation at national level, and the historical evolution has created strong disparities between national energy sectors. Various attempts to cooperate on transnational infrastructure have ended up as costly failures in past years.The aim of this PhD work, half of which was conducted in France and half in Chile, was to develop a mathematical model adapted to the study of long-term energy issues, at a regional scale, for South America. This model, TIMES-América Latina y el Caribe, was applied to studying the impact of national climate policies on regional energy, as the world prepares for a global climate agreement at the Paris conference in December 2015.This document is divided in five chapters. Chapter 1 offers a historical overview of South America's history with a focus on the energy sector, followed by a description of the specificities and challenges of South American energy today. Chapter 2 presents the concepts of prospective and scenario modeling, along with a historical overview and a state-of-the-art of energy prospective in South America. Chapter 3 details the model's main features: its ten-region disaggregation, its modeling rules and the structure and main assumptions for supply and demand, including macroeconomic drivers, resource potentials, and extraction costs. Chapter 4 presents the climate change issue and its implications for South America; it also describes the international climate negotiations, from their beginning in 1972 to the current tentative contributions. Finally, chapter 5 analyses the impacts of these pledges on South America's energy sector, and the contribution of the latter to fulfilling these pledges, as a direct application of the model developed in this thesis.