What is geothermal energy primarily derived from?

Geothermal energy is primarily derived from the heat that originates from within the Earth's interior. This heat is produced through various processes, including the decay of radioactive isotopes and residual heat from the planet's formation. This internal heat can be found in the form of steam and hot water, which can be harnessed and used for electricity generation or direct heating applications. The significant temperature gradient and naturally occurring heat sources in regions with volcanic activity or tectonic movement make geothermal energy a viable renewable resource.

The other options, while important energy sources in their own right, do not pertain to geothermal energy. Wind energy is influenced by atmospheric patterns, solar energy is derived from sunlight, and kinetic energy from rivers relates to hydroelectric power, making them distinct from the processes involved in capturing geothermal energy.