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Hydropower, also known as hydroelectric power or water power, is the use of water to produce electricity. Generally, it captures the force and energy of fast-running water in rivers. Hydropower is considered a renewable and sustainable source of energy production. Although, hydropower stations are also known to disturb the natural environment.

Hydroelectric power is one of the oldest sources of renewable energy. It started about 2000 years ago as the energy of water was captured to turn the wheel in mills. Hence, hydropower has traditionally been used to power machines.

Global overlook

Globally, hydropower stands for about one-sixth of the total electricity supply. As the largest amount of energy still comes from fossil fuels such as oil, coal and gas. According to Statista, China is the largest producer of hydroelectric power in the world. Followed by Canada, Brazil and the US. Some smaller nations with large water sources are also at the top, such as Norway and Sweden. Although China is the biggest producer, hydropower stands for about 17 % of the nation’s total energy needs. While the source covers about 90 % of all power generated in for instance Norway. In fact, Norway is the biggest producer of hydropower in Europe.

Hydropower dam in contruction.

Hydropower explained

As mentioned, hydroelectric power captures the natural force and energy of fast-moving water in rivers. The source can be regulated, meaning electricity can be produced when electricity is needed. The most common hydropower stations stores water in a dam. Then, when the water is released from the dam, the energy of that movement is captured. For example, by letting the water turn the blade of a turbine. Which then generates electricity that can then be distributed to a community.

There are three kinds of so-called hydroelectric energy plants. The one described above is known as an impoundment facility. Namely, when water is released from a dam to make a turbine spin, which then powers a generator. Another kind is called a diversion facility. It works by channelling water in a series of canals, instead of a dam. The third type is called a pumped-storage facility and is used in combination with for example solar and wind power. It collects the energy from these sources to pump water uphill to a dam or pool. When there is a need for electricity, the water in the higher pool is released to turn a turbine.

Debate about hydropower

Hydropower is considered a sustainable source of energy. The benefits of hydropower are usually highlighted in the global debate for sustainability. Mainly, because it uses the natural power in the water. But also, because it is the only renewable source that can be regulated. As solar and wind power only generate electricity when there is sun and wind. Although, the storage of these energy sources is getting better.

However, the major constructions that are required to build hydroelectric power stations disturb the environment. They drastically change the landscape and rivers where they are built. More so, they interfere with, for example, the natural movement of fish. As fish tend to move up and down the river. The ecosystems of rivers depend on this movement in a complex web. For example, fish also brings nutrition to the landscapes and animal life around the water source. This tends to be considered by creating water passages. Yet, the facilities remain a blockage to the natural flows.

More so, the disturbance can have a great negative effect in areas such as the Amazon rainforest. Not only environmental but also social. For example, huge constructions of dams tend to lead to misplacing the people that live by the rivers.

Furthermore, hydropower is usually known as a source that doesn’t release greenhouse gases. This is not correct. First of all, the construction of the facilities releases greenhouse gases. But most importantly, the facilities release the powerful greenhouse gas methane.

Future outlook

Overall, the debate around hydropower is coloured by greenwashing and defining what is truly sustainable. Meeting the current energy demand of the world with renewable sources also has its complications. The most logical course of action is to lower the energy demand and work with energy efficiency. More so, work to protect nature and its biodiversity.

Sources: National Geographic, The Guardian, Statkraft, Statista, Our World in Data.


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