The most widely used renewable energy source is hydropower. While this has many benefits, it also causes many environmental concerns when the dams get built.
This is the most widely used renewable energy source due to its abundance, meaning each region with sufficient water flow could generate its own power. It is a clean source of energy and as such there's little concern for pollution. These among many other reasons has made Hydropower to account for about 54% of the world's installed renewable energy source and accounting for over 16% of the total energy produced in the world. It remains the world's primary, and most valuable, source of renewable energy.
