Hydropower: Explore the Power of Water

Hydropower: Explore the Power of Water

The 20th century is the century of fossil fuels and oil. It is a century of pollution, environmental destruction and irresponsibility. Now that we are in the 21st century, we can begin to think of what this century will be known as, and considering the push by the Obama Administration for green jobs, it could be the century of renewable energy.

One form of renewable energy that actual predates nearly all other forms of energy is hydropower. Hydropower has actually been around for centuries. In India, as well as Rome, mills were powered by water wheels for the production of everything from grain to timber. With the power of the water, usually a river, moving by the mill, the wheel outside the mill would be pushed, helping to create energy through pulleys and levers within the mill.1

These days, hydropower is used for much more than just power mills. In the 21st century, it is powering the homes of millions of people and helping our civilization move from one that used dirty coal and oil, to one that uses the clean and renewable energy that is all around us.

How Is It Generated?

Hydropower is actually generated quite simply. As long is there movement of water, it is possible to generate power because water is 500 times as dense as air. Even a slow stream will generate power as a result. When the water moves through a dame, or a confined space, it begins to rush faster as a result of more water going through a smaller space. When it does this, it turns turbines that then help to power a generator. The generator then sends power into batteries and convertors in order to send power out or store it.

Types of Hydropower

Hydropower, specifically for the generation of electricity, comes in many forms beyond just the dams we all know and recognize. There is of course the dams, but also tidal power and wave power 2.

Currently, hydroelectric power supplies 19 percent of the world’s energy, which amounts to nearly 715,000 megawatts 3. Most of this comes in the form of large dams, like the Three Gorges Dam in China and the Hoover Dam in the United States.

The great thing about producing hydroelectricity in this manner is that there is no carbon dioxide emissions, or any burning of fossil fuels. For a world that is getting warmer due to rising CO2 levels in the atmosphere, this is good new.

Tidal power is another method of hydroelectricity generation that has become very popular in France and Russia, as well as in Canada, which has the largest tides in the world at the Bay of Fundy. By harnessing the energy of the tides moving in and out of the bays or estuaries, it is possible to generate large amounts of energy. While it is predictable, this form of energy generation is not able to follow the changing in electrical demand like hydroelectricity from dams can.

Wave power can also be used to generate hydroelectricity. By harnessing the power from ocean surface wave motions, it is possible to generate much more electricity than can be achieved through tidal power. By having floating generates that are turned by the air that is displaced by waves in hollow concrete structures, it is possible to create this electricity. While it is still in its early stages, countries like the United Kingdom are jumping onto this new hydropower bandwagon. One prototype device located at Port Kembla in Australia is expected to create 500 megawatt hours of power per year 4.

Advantages of Hydropower

So, what exactly are the advantages to this form of power generation then? Well, there are three main advantages, all of which are incredibly important to the long-term survival of our civilization in many ways 5.

The first is economics. Unlike fossil fuels, where oil, coal and natural gas has to be taken out of the ground, water is all around us and whether we use it or not, it is moving by and creating energy. Hence, there is no cost of fuel with hydropower. The Three Gorges Dam for example will cover the costs of its construction in as little as five years of full generation.

As well, fossil-fuel fired plants require a lot of service and only last about 50 years. However, hydropower plants that were built 100 years ago are still in generation, making them much more cost effective. Dams and other hydropower plants also use less people on site, thereby lowering costs even more.

As has been mentioned, hydroelectric plants and dams do not burn fossil fuels and therefore do not contribute to greenhouse gases and climate change. The only greenhouse gases that are produced by the plant and dam are those that are emitted during its construction, which are easily offset within a few months of the dam or plant’s use.

Reservoirs crated by dams also help to bring in tourists. The Hoover Dam is one of the biggest tourist attractions in the United States, and many towns take advantage of the water sports made possible by dams, thereby contributing tourism dollars into the area. Some multi-use dams also install irrigation support to provide water supplies for farmers, and even help prevent floods downstream.

Who Generates The Most Power?

In terms of the generation of hydroelectric power, those countries with many rivers generally lead the way in power generation. China is the number one producer of hydropower in the world with 563 terawatt hours. While Brazil, Canada and the United States come in second, third and fourth. Of those countries, Brazil and Canada use hydropower to handle 85 and 61 percent of their power needs. Hydropower takes care of 17 and five percent of the power needs of China and the United States however.6 Norway on the other hand produces 135 terawatt hours of hydropower but it generates an astonishing 99 percent of its energy this way.

Ten Largest Dams On Earth 

NameCountryYear of completionTotal Capacity (MW)
1Three Gorges DamChina200922,500
3Guri (Simón Bolívar)Venezuela198610,200
5Sayano ShushenskayaRussia1985/19896,400
7Grand CouleeUnited States1942/19806,809
8Robert-BourassaQuebec, Canada19815,616
9Churchill FallsCanada19715,429
10Longtan DamChina20096,300


While solar and wind power can create more energy than hydropower can, they are still in their infancy in terms of development. Hydropower has existed for hundreds of years and is available anywhere that there is movement of water. With some countries like Norway and Brazil generating over half of their electricity this way, it is only a matter of time before other countries follow suit and begin to catch up.

It is ironic that to move into the future of energy, we have to look at the past, at something as basic as a watermill. Sometimes going retro is good, as it is with hydropower.

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