Hydropower ⚡ Understand Energy with Data

What is Hydropower?

Hydroelectricity, or hydropower, is a renewable energy source that creates electricity from the flow of water. Captured by turbines, the power of water from rivers and waterfalls drives alternators that generate electricity.

Dams were already used in ancient Greece and China and expanded in the medieval period to grind grain. First invented in the 19th century, the first hydroelectric turbine was installed in 1895 at Niagara Falls and still operates today. This power source has grown rapidly since the beginning of the 20th century, producing 4206 TWh in 2021, four times more than in 1970.

As the first source of low-carbon energy before nuclear energy (9.9%) and the first source of renewable energy ahead of wind (6.6%) and solar (3.7%), hydropower produces 15.3% of the world's electricity. China has tripled its hydropower production from 436 TWh in 2006 to 1262 TWh in 2020. Furthermore, 55.9% of Brazil's electricity and 60.6% of Canada's electricity comes from hydropower.

In addition to its classic role of electricity production, hydropower dams can be used to store energy by pumping water upwards. Storage can potentially help compensate for intermittent energy sources such as wind and solar power.

Is Hydropower a low-carbon energy source?

Yes, due to its relatively low lifecycle emissions, Hydropower is considered to be a low-carbon energy source.

The median estimate of lifecycle emissions from Hydropower is 24 gCO2eq / kWh. Where do our emissions numbers come from?

Wind	11 gCO2eq / kWh	Low-carbon
Nuclear	12 gCO2eq / kWh	Low-carbon
Hydropower	24 gCO2eq / kWh	Low-carbon
Geothermal	38 gCO2eq / kWh	Low-carbon
Solar	45 gCO2eq / kWh	Low-carbon
Biofuels	230 gCO2eq / kWh	Low-carbon
Gas	490 gCO2eq / kWh	High-carbon / fossil fuel
Oil	650 gCO2eq / kWh	High-carbon / fossil fuel
Coal	820 gCO2eq / kWh	High-carbon / fossil fuel

Hydropower compared to other low-carbon energy electricity sources

Most significant producers of electricity from Hydropower

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What are the pros of hydroelectricity?

To reduce global warming, hydropower has several advantages. It is a renewable energy known and mastered for a long time. It emits very small amounts of greenhouse gases. It provides storage capacities to the grid that combine well with other renewables such as wind and solar. It also provides electricity at a competitive price.

Hydropower can help reduce global warming

Firstly, hydropower is a renewable energy source that can generate significant amounts of electricity, 55.9% in Brazil and 60.6% in Canada for example, with very little contribution to global warming.

Indeed, it is one of the low-carbon energy sources that emits the lowest amounts of greenhouse gases to produce electricity (24 gCO2eq / kWh), unlike natural gas (490 gCO2eq / kWh) and coal (820 gCO2eq / kWh).

Hydropower is cheaper than coal and on par with gas

Second, hydropower prices average $72 USD/MWh according to the IEA. To compare, onshore wind costs $50 USD/MWh, solar costs $56 USD/MWh, gas costs $71 USD/MWh, and coal costs $88 USD/MWh.

Although the upfront investment for hydroelectric power plants is substantial, it largely pays for itself over time because their lifespan is almost infinite. For example, the hydro turbines installed on Niagara Falls in 1895 are still in use today.

https://www.iea.org/reports/projected-costs-of-generating-electricity-2020

Used since the 6th millennium BC, hydraulic energy keeps improving

Hydraulic power was first used in the 6th millennium BC in ancient Egypt. Signs of the first-known dams were discovered on the Nile River, which helped to cope with flooding and crop irrigation.

This technology was also used in ancient Greece by the Minoan civilization from the second millennium BC and in China from the second century BC.

https://www.mdpi.com/2071-1050/12/22/9760/pdf

http://www.history.alberta.ca/energyheritage/energy/hydro-power/hydro-power-in-ancient-times.aspx

https://www.hydropower.org/iha/discover-history-of-hydropower

Benoît Fourneyron invented the first hydroelectric turbine in 1827. This technology produced electricity from waterpower and experienced rapid development in the 19th century in France and then in Germany. Installed on Niagara Falls in 1895, it is still used today.

Hydroelectricity then developed massively in industrialized countries throughout the 20th century. Thus, the electricity produced from hydroelectric power increased fourfold between 1970 and 2021, accounting for 15.3% of electricity worldwide. Hydropower is thus the first source of low-carbon electricity. It comes in ahead of nuclear power, which represents 9.9%, followed by wind power (6.6%) and solar power (3.7%).

Hydroelectricity is a renewable energy source

Hydropower is a low-carbon and renewable energy, as are wind, solar, and geothermal energy. Indeed, once the dam is installed, it needs nothing more than the natural force of water, unlike fossil fuels that require fuel to generate electricity.

Using hydropower as energy storage

Hydropower has a key feature to achieve net-zero; it can stock energy on demand. When intermittent renewable energies (wind and solar) produce a lot of electricity, the water can be pumped upstream into the dams. And when intermittent energies produce less, stored energy from hydro can be used to compensate and thus stabilize the electricity grid.

What are the cons of hydropower?

Upfront investment in hydroelectric facilities is high.

Many hydropower facilities are major infrastructure projects requiring building dams, reservoirs, and power-generating turbines, resulting in a significant financial investment.

Therefore, the upfront construction costs are often significant. However, these facilities often last between 50 to 100 years (sometimes even longer), which make them a worthwhile investment. Niagara Falls has been in operation since 1895. This long lifetime results in a competitive average cost of between $68 USD and $72 USD/MWh. This price is more expensive than other renewables such as onshore wind ($50 USD/MWh) and solar ($56 USD/MWh), but it is equivalent to gas ($71 USD/MWh) and much cheaper than the most polluting energy to produce electricity: coal ($88 USD/MWh).

https://www.iea.org/reports/projected-costs-of-generating-electricity-2020

Hydropower facilities can have negative effects on the local environment

Hydropower, although a renewable energy source, can harm the local environment because of the implementation of hydroelectric facilities.

First, dams modify the natural flow of rivers, which can disrupt ecosystems. Secondly, in some cases, local populations may be displaced. Finally, in some cases, as in Egypt, historical monuments can be submerged by the dam.

These side effects of hydropower are generally lower with run-of-river facilities such as wave or tidal installations. However, most current hydropower systems are dams that block the flow of rivers. Based on existing case studies, new techniques are being developed to try to reduce the environmental impacts of hydroelectric dams.

https://www.science.org/doi/10.1126/science.aaq1422

Hydroelectric facilities are dependent on local geography and weather factors

While hydropower is a reliable source of energy, it cannot be installed anywhere as the installation of dams depends on the local geography.

On the other hand, the operation of dams depends on meteorological trends and especially on rainfalls. Since most hydroelectric plants depend on river water, droughts hurt hydroelectric production since they result in lower water flows. From month to month and year to year, the amount of water available to hydroelectric systems can therefore vary, affecting hydroelectricity production.

Major dam accidents can have catastrophic consequences

According to OurWorldInData, hydropower together with solar energy is the safest energy sources in the world at just 0.02 deaths per TWh. It is 1636 times safer than brown coal.

Nevertheless, out of all energy sources, hydroelectric dam accidents are the deadliest. In China, the Banqiao Dam failure in 1975 killed about 85,000 people and generated between 220,000 and 230,000 total deaths from famine and disease created by this tragedy.