Which renewable energy sources provide the most constant source of energy?

The answer is hydroelectricity.

The technologies encourage sustainable energy including renewable energy sources, like solar energy, hydroelectricity, wave power, wind energy, geothermal energy, tidal power, and bioenergy.

Of these the most constant source of energy is provided by hydro-electricity. The gravitational force of falling water is the essential feature in the generation of hydroelectricity. The micro-hydro or the small-scale hydro has become a popular substitutive source of energy, mainly in remote regions where other power sources are not viable.

the scientific method.