Answer: Water

When it comes to generating enormous amounts of energy, water-driven facilities are king. The top five power producing energy facilities world wide are all hydroelectric (and of the top ten, eight are hydroelectric).

In fact the top producing facility in the world, the Three Gorges Dam, produces just shy of 100 terawatt hours of energy per year. The output of the facility is more than the 8th, 9th, and 10th top producing facilities combined. Further, the power production capacity of the Three Gorges Dam project is so high (it has a 22,000 MW output capacity) that it’s capacity exceeds the combined capacity of the top three facilities combined from every other category such as nuclear, coal, natural gas, and so on.

To put the sheer scale of the Three Gorges Dam power output in perspective, let’s compare it to the best known, albeit not the biggest, hydroelectric dam project in the United States, the Hoover Dam. It would take the Hoover Dam approximately 23.5 years to generate as much electricity as the Three Gorges Dam generates in a year. Even the largest hydroelectric project in the U.S., the Grand Coulee Dam located on the Columbia River in Washington state, would still take approximately five years to match the single year output of the Three Gorges facility.