Solar energy is generated using solar panels that face the sun and gather the energy. Hydroelectric energy is generated by rushing water. The intense pressure creates a large amount of energy. Basically, solar energy uses the sun, and hydroelectric energy uses water.
Technically, hydroelectric energy ultimately comes from the sun. This is because the sun's energy heats up water, moving water through the water cycle. Hydroelectric energy is generated by harnessing the power created by the movement of this water.
the difference between the hydroelectric energy and the hydrothermal is hydrothermal is using geothermal heat (hot rocks) to create electricity by pumping it while the hydroelectric energy it uses the high dams and waterfall to create electricity.