The energy sector currently accounts for more than two-thirds of global greenhouse gas emissions. There is an urgent need to accelerate the energy transition to a decarbonized supply system. Renewable energies have a decisive role to play in this transition. However, the dependence of renewable resources on atmospheric conditions gives them an inherently intermittent character, which can lead to episodes of energy deficit, and makes them, in turn, potentially vulnerable to climate change. On the other hand, however, this dependence gives them a certain predictability and spatio-temporal complementarity, particularly between solar and wind resources. Faced with the challenge of achieving a decarbonized and stable energy system, the integration of renewable energies into it requires an exhaustive resource assessment and planning exercise that takes into account their spatio-temporal variability and their evolution in the medium and long term, and that deepens the understanding and characterization of the complementarity between resources as a strategy to reduce the intermittency of total production.