By means of a multidisciplinary approach, this proposal aims at addressing the characterization, in the Iberian Peninsula, of one of the main ground effects of space weather on Earth: that derived from what are known as geomagnetically induced currents or GIC. These currents are produced in long terrestrial conductors as a result of geomagnetic storms, and may affect pipelines, railways and power supply, the critical infrastructure from which society has become more dependent. The main challenge of the proposal is to analyze and characterize the magnetosphere-ionosphere-earth electromagnetic coupling and to improve the accuracy of the vulnerability map of the Spanish high voltage power transmission network in front of the GIC. To do this, i) we will characterize the magnetospheric and ionospheric sources that generate the greatest GIC and how they are related to coronal mass ejections and solar flares, as well as the solar wind velocity, the incidence angle and the local time when the compression magneto-hydrodynamic wave reaches the Earth; ii) a geoelectric model will be determined on a lithospheric scale in the Iberian Peninsula to predict how the 3D structure of subsurface resistivity and network topology affect GIC; and iii) GIC intensities at critical locations will be obtained in a non-invasive manner, i. e., without interfering with the operations of the network or power plants. Improving GIC estimation by integrating geophysical models and transmission grid models will enable accurate mapping of geoelectric field variations and vulnerability maps of the power grid. These maps will allow the power grid operators to design strategies of resilience and mitigation of impacts considering different scenarios and also to identify critical aspects in the infrastructure, with the corresponding economic and social benefit at national level. The 3D model of electrical resistivity of Iberia, which will be obtained by integrating previous magnetotelluric soundings and new data through the surveys planned in this project, will be the first reference map, will serve as a basis for subsequent geophysical studies and will be an indispensable contribution for all international projects in this area. Finally, the contribution to the knowledge of this natural hazard, as well as its diffusion to the society, will generate a real and founded perception of its vulnerability and will allow taking the appropriate measures on a founded basis.