Answer: Hydropower (Hydroelectric power)
Step-by-step explanation:
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.