Hydroelectricity = Potential energy to electrical energy.
Photovoltaic solar energy = Radiant energy to electrical energy.
Solar thermal energy = Thermal energy to electrical energy.
Note: The difference between thermal solar energy and photovoltaic solar energy is that, for photovoltaic energy special panels should be used that convert the solar incidence into electrical energy, while solar energy panels are used to heat water or other similar fluid, either for hot water supply or steam generation, to supply this to a turbine.
