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Advantages & Disadvantages of Hydroelectric Power

Hydroelectric power (commonly referred to as hydroelectricity) is the most widely used form of renewable energy due to the many advantages associated with it. There are however some significant disadvantages associated with generating hydroelectricity. In this article we’ll take a look at the many different advantages and disadvantages of hydroelectric power whilst highlighting the key pros and cons of the technology.

Advantages of Hydroelectric Power

Here are the many advantages associated with hydroelectric power.

1. Reliable & Efficient

Hydroelectric power is widely considered both a reliable and efficient electricity source. Providing there exists an adequate supply of water, hydroelectricity production can be constant and some countries have been successful in producing a large proportion of their total electricity capacity from it. Paraguay has been able to produce almost 100% of its electricity supply from hydroelectric power.

2. Clean & Renewable

Another advantage of hydroelectricity is that it is both clean and renewable. No fossil fuels have to be burnt to produce hydroelectricity and therefore there are no harmful emissions as a result. Water is a renewable energy source that will never run out and the use of this resource helps to conserve non-renewable energy sources for other uses. This also allows countries to become less reliant on external supplies of fossil fuels such as coal, oil and natural gas which can become disrupted due to conflict, the economy and supply and demand.

3. Flexible

Hydroelectric dams have a degree of flexibility when it comes to meeting real-time energy demands. When high or low volumes of electricity are required, operators of a hydroelectric dam can alter the water intake to increase or decrease the flow of water into the dam thus generating the right level of electricity. This alteration can be completed in a very short space of time when compared to traditional power stations.

4. Economical

Hydroelectric power is very economical to produce once the initial hydroelectric dam has been constructed. Hydroelectric dams have very low operating and maintenance costs when compared to those of more traditional power stations. Tied in with the economical advantages is the fact that hydroelectric power isn’t vulnerable to the fluctuating cost of fossil fuels, helping to provide a more stable economy with predictable energy prices.

5. Additional Uses

Hydroelectric dams are often designed to create a large reservoir to one side of the dam wall. This body of water is commonly used for not only producing electricity via the dam but also for providing a water supply to surrounding towns and cities. This reduces the cost of building a separate reservoir to supply the water.

6. Recreation & Tourism

The reservoir created during the construction of a hydroelectric dam can also be used as a recreational facility with many home to kayaking and windsurfing facilities. In addition, the larger, more noticeable hydroelectric dams can become landmarks for a country or region helping to bring in large volumes of tourists each year providing a boost to the local economy.

Disadvantages of Hydroelectric Power

The above pros of hydroelectric power clearly show why many countries have chosen to tap into the potential of this energy source. Below you will find the various disadvantages associated with hydroelectric power.

1. Environmental Impact

As mentioned previously, when a hydroelectric dam is built, a reservoir is formed behind one face of the dam wall. Depending on the size of the dam, this can have an impact over a large area as land is flooded as the reservoir fills which brings disastrous consequences for wildlife, fish and even plants. Changes in river levels, flow patterns and water temperature all contribute to how severe this impact will be.

Not only does the local environment suffer but so does the environment of areas downstream. Depending on the scale of the reservoir and how much water it holds back, large areas many miles downstream could be affected by drought and other consequences. This can also have an impact on international relations should one country cause an environmental disaster in a neighbouring country.

We have a page dedicated to the environmental impacts of hydroelectric dams.

2. Displacement of People

Often, when land needs to be flooded to form a reservoir for a hydroelectric dam, people will be displaced. Villages and even small towns may have to relocate to make way for a reservoir, destroying communities in the process. Although financial incentives are often provided to persuade people to relocate, others may be forced to relocate from the place they’ve called home for many years.

3. Expensive To Build

Hydroelectric dams are notoriously expensive to build. Lots of planning, engineering and construction is required before a dam can start producing power to start paying for itself. This process takes many years and results in a long pay back or return on investment (ROI).

4. Limited Places To Build

As hydroelectric dams have to be built in areas with the perfect conditions (landscape, precipitation levels etc.), the majority of these places have already been used for hydroelectric dam construction. Nowadays there are limited places where we can build new dams that will provide the highest reliability and efficiencies.

5. Safety Concerns

Although the safety levels of modern dams are considered good, there are fears over the safety of older dams. There have been numerous disasters relating to dam failure with the most notable taking place in China in 1975 which killed 171,000 people.


We can see from the above pros and cons of hydroelectric power that there is a case for and against the technology. On one hand hydroelectricity is capable of providing a source of clean, reliable and renewable electricity whilst on the other hand hydroelectricity can destroy habitats and displace people.