How does hydropower work?

Hydropower works by extracting energy from flowing water. Water flowing through a turbine in turn drives a generator that produces electricity.

11 August 2022

Maria Blomberg

Hydropower works by extracting energy from flowing water. Water flowing through a turbine in turn drives a generator that produces electricity. There are a few different variants of hydropower plants. On the one hand, you can have turbines that use temporary water currents. An example of this is hydropower plants located along rapids with meltwater from the mountains. Here, there are temporary currents that the power plant can use.


There are also variants of hydroelectric power plants where the currents that arise in water from temperature differences are used. These currents as well as so-called tidal currents can also be used to extract energy. Hydropower is a renewable energy source and a very important part of the work that is currently underway to reduce human emissions of carbon dioxide. Did you know that SenseNode performs energy mapping?

How does hydropower affect the environment?

A hydropower plant in operation has no direct emissions into the environment, which means that hydropower is counted as a renewable energy source. The main thing you need to look at when building a hydroelectric plant is how fish move in the local areas. It is generally recognized that hydropower has a very negative impact on both fish and plants. The reason is partly that there are unnatural rises and falls in the water level in connection with the hydropower plant.


Some species of fish have almost been completely eradicated in Swedish dams used for hydro power. An example is the trout. The pearl mussel, which lives its first years in the gills of the trout, has also been threatened because of this.

Advantages of hydropower

The big advantage of hydropower is that it does not contribute any emissions of carbon dioxide into the atmosphere. Global warming is a serious problem right now for humanity, which is why renewable energy sources are getting a lot of attention right now.


Hydropower can never measure up in efficiency when compared to nuclear power, but is however a significantly safer alternative and which also does not leave any environmentally hazardous waste. Together with other renewable energy sources, such as wind power and solar cells, hydropower plays an important role. On cloudy days and when there is no wind, you can easily open dams and release water into the hydroelectric plant, thus balancing the total energy production to the grid.


An investment in hydropower is beneficial in the long term. What drives the hydroelectric plant are the water currents and these are there constantly. The fuel itself is thus free and infinite. A lot of research and development is currently being conducted on how to make hydropower even more efficient and, above all, how to minimize the impact it has on the surrounding environment.

Disadvantages of hydropower

Even if hydropower does not have any negative effect on the environment globally, the problems with the impact on the local environment need to be solved in order for hydropower to take up the hunt for the large energy sources. There needs to be a way for fish to get past the turbines without getting stuck or injured.


A difficulty with hydropower is that you become geographically tied precisely to watercourses and streams. It can sometimes involve large and extensive projects to get cables to and from the hydropower plant and out into the large electricity grid. Therefore, hydropower plants need to be carefully planned and weighed against other alternatives, such as wind power and solar power.

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