Advantages and disadvantages of hydroelectric dams

In this presentation, we will mainly present the advantages and disadvantages of hydroelectric dams!

My presentation is divided into five main parts. First, I will give the definition of hydroelectric dam. Then I will discuss about a brief history of hydropower’s use. After that I will talk about benefits and disadvantages of a hydroelectric dam. And finally, I will conclude with the potential of production.

We’ll begin with the definition of a hydroelectric dam.

  • Definition of a “hydroelectric dam”:

Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power by using the gravitational force of falling or flowing water”. The way hydroelectric dams function is closest to that of watermills. The main difference is that instead of turning a wheel, the water makes a turbine turn, the water makes a turbine turn, the which makes a generator run, to convert mechanical energy into electrical energy. Finally, a power transformer loads to adjust the electricity’s voltage produced in order to inject it into a network of electricity transmission. This is also another major difference. The energy produced by the water is no longer used on site, but in another place.

  • Brief history of hydropower’s use:

Hydropower has been used for centuries in order to serve human activities. Indeed, the first signs of its use can be traced back to the period of Antiquity. Back then; this energy was used as a mechanical force to operate water mills. These water mills were generally used to grind grain to make flour, to saw wood or to extract oil. Its operation was rather simple. The water turns, either by the force of its flow (kinetic energy), or by gravity a wheel. The latter sets an axle in motion which in turn sets in motion a set of gears. All these transmit their energy to rotate the grinding wheel.

  • Benefits of hydropower:

The first advantage of hydropower is that this energy satisfies the definition of sustainable development, a goal which represents a major challenge for the future of the planet. As a reminder, sustainable development is characterized by three pillars: social, economic and environmental.

Socially, hydropower sector should create jobs around the world.

Economically, there should also be positive effects. Indeed, hydropower is expected not only to create new jobs but also to expand or convert old industries.

Thus, the development of this energy, like other renewables, should provide a new impetus to Europe’s aging industries like the automotive sector.

Finally, in terms of the environment, the development of this type of energy can respond to European issues such as the EU 2020 strategy. Indeed, hydropower can contribute to energy independence and to the EU’s energy security. It also helps produce cleaner energy such as that produced from oil or gas.


Although this energy is used to limit the impact on the environment, we will see in the next section that this energy can also have a negative impact on the environment.

  • Disadvantages of hydroelectric dam:

Example of the variability of water resources in Algeria.

As we can see in this graph, the first disadvantage of hydropower is the variability of this resource. This energy is very variable from one month to another, but also from one year to another. If we take for example the month of December, the average rainfall between 1976 and 2002 was approximately 10 millimeters, while it was about 50 millimeters between 1949 and 1976.

The second disadvantage is that the water, instead of flowing normally, is canalized and water stagnate to the tank. This stagnant water has many environmental impacts such as reduced oxygen in the water.

The third major consequence is that the dam creates the phenomenon of gradual silting of the tank.

Indeed, the dam prevents sediment be able to flow with the water downstream. Again, this is an issue that is highly variable depending on the location of implantation. This is a real problem for the operation of the dam because the gradual silting up of the reservoir water will lead to the decrease in both the total storage capacity as well as energy production.

Finally, a dam can cause the displacement of the population living on the water.

  • Hydroelectric dams potential:

Production potential of hydropower is estimated to be at 18,000 TWh. However, if one takes into account the likely profitability of its projects, this potential is at more than 9,000 TWh. This figure is nevertheless important compared to the total energy production in the world which is at about 20,000 TWh. In terms of investment potential, it is a very interesting energy. In fact, it is estimated that currently there are about 3,200 TWh of hydropower installed around the world. This represents only half of the total production capacity.



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