Geothermal energy is a renewable energy source that harnesses the heat from within the Earth to produce electricity or provide heating. This heat originates from the Earth's core and from the radioactive decay of elements, creating a geothermal gradient that can be exploited in certain regions. The geothermal course covers the origin and distribution of this heat, the types of reservoirs (hydrothermal, hot dry rocks, and geopressurized systems), and the exploitation techniques such as deep drilling and geothermal power plants (dry steam, flash steam, and binary cycle). Geothermal energy is used not only for electricity generation but also for direct heating in buildings, greenhouses, and spas. Although it is a clean and continuous energy source, it faces economic and geological challenges, such as the high cost of drilling and limited suitable locations. The goal of the course is to understand the physical principles, technologies, and applications of this sustainable energy within the context of the global energy transition.