Dams have been around for a century now. Beavers have used them, although not for energy and now humans employ them as source for that ingredient in survival: power.


Hydropower generates hydroelectricity. It produces power with the help of gravity. It is the most common alternate source of energy. After the dam (called the hydroelectric complex) is built, the complex produces no waste whatsoever. Hydroelectric power comes from water’s potential energy.

Imagine a glass bubble, and you’re in it. When the walls crack water exerts pressure on that one hole until water comes through that tiny gap. It’s the same thing with a dam. The engineers collect the dam’s power by harnessing it with the use of a turbine which is then connected to a generator. In this matter the power extracted from the rushing water depends on the amount of force the water exerts on the turbine and on the difference of the water’s average gravitational pull. The difference between the height and the outflow is called the head.

The amount of the water’s potential energy depends on how high the dam is from its outflow. Dams help cities by supplying energy during extremely high demand times, and during off peak the turbines pump water into higher reservoirs for when electricity consumption is high again.

Where The Power Is Supplied

Most hydroelectric power plants supply public entities; there are some which are funded by industrial companies for their specific use. Such industries like aluminum electrolytic plants build their own hydroelectric power plants due to their high energy consumption. In fact, the world’s largest dam, the Coulee Dam, located in Bellingham, Washington, was switched to support the Alcoa Aluminum plant, which at the time was the largest supplier of materials for war planes; afterwards though it was used for public electricity and as a source for irrigation.

There are also small-scale hydroelectric power plants; most of them are located in north America. A plant is classified as small scale when it only produces 10-30 megawatts. These power sources are usually connected to power grids to supply energy to small isolated communities or even to a single family home. In China, small hydro schemes are very popular due to a high number of factories wishing to have their own supply of electricity.

Other Common Water Energy Sources

Other common hydro resources are rivers, the ocean, waterfalls and even ponds or lakes. Rivers can power plants where no reservoir can be built called run-of-the-river, while the ocean is put into good use because of the tides. A tidal power plant harnesses the energy of the coming and the going of the tides. Uncommon, but never the less employed, are kinetic energy water plants.

Why It Makes Sense

Economically the use of hydropower is cost effective because our primary source of fuel – fossil fuel – is expensive and slowly getting used up. Water is in abundance, and most of the time it is free. Granted that dams and other hydroelectric power plants are quite expensive to build, but the pros far out weigh the cons. The operating and maintenance cost of a hydroplant is considerably cheaper than looking for fossil fuel, drilling for it, and refining it to become oil. What’s more, a hydroelectric power plant cannot be affected and is not subject to the rise and fall of fuel prices.