Is Hydroelectric Power Renewable Or Nonrenewable?

Hydroelectric power has long been considered a source of clean, renewable energy. But some argue that the environmental impacts of hydroelectric dams mean the power source is not as ‘green’ as it seems. In this comprehensive article, we’ll examine both sides of the debate in detail.

If you’re short on time, here’s a quick answer to your question: Hydroelectric power is generally considered a renewable energy source, but it also has some attributes of nonrenewable sources due to its environmental impacts.

What is Hydroelectric Power and How Does it Work?

Hydroelectric power is a form of renewable energy that harnesses the power of flowing or falling water to generate electricity. It is considered one of the most reliable and widely used renewable energy sources. Hydroelectric power plants use the force of water to turn turbines, which then generate electricity. This clean and sustainable energy source has been used for centuries and continues to play a significant role in meeting the world’s energy needs.

Definition of hydroelectric power

Hydroelectric power, also known as hydropower, refers to the electricity generated by harnessing the energy of flowing or falling water. It relies on the gravitational force of water to generate mechanical energy, which is then converted into electrical energy. This process involves the use of dams or reservoirs to store water, which is then released through turbines to produce electricity. Hydroelectric power is considered renewable because it relies on the natural water cycle, which is continuously replenished by precipitation.

Overview of how hydropower dams work

Hydropower dams play a crucial role in the generation of hydroelectric power. These dams are built across rivers or streams to create reservoirs, which store large amounts of water. When the water is released from the reservoir, it flows through penstocks, which are large pipes that direct the water to the turbine. As the water flows through the turbine, the force of the water causes the turbine to spin. The spinning turbine is connected to a generator, which converts the mechanical energy into electrical energy.

Hydropower dams offer several advantages. They provide a reliable source of electricity, as water is constantly replenished by rainfall and snowmelt. They also help regulate water flow, preventing floods during periods of heavy rainfall and ensuring a steady water supply during dry seasons. Additionally, hydropower dams have the ability to store excess electricity generated during times of low demand, which can be used during peak hours.

It is worth noting that while hydroelectric power is considered a renewable energy source, the construction of large dams can have ecological and environmental impacts. It can alter river ecosystems, displace communities, and affect fish migration patterns. However, advancements in technology and increased focus on sustainable practices have led to the development of smaller-scale hydropower projects that minimize these impacts.

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Arguments for Hydroelectric as Renewable

Hydroelectric relies on the water cycle, a renewable process

One of the main arguments for considering hydroelectric power as renewable is that it relies on the water cycle, which is a continuous and naturally occurring process. The water used in hydroelectric power plants comes from rivers, lakes, or reservoirs, and is then converted into energy through turbines. Unlike fossil fuels, which are finite resources that take millions of years to form, water is a renewable resource that is constantly replenished through evaporation, condensation, and precipitation. This means that as long as the water cycle continues to function, we can continue to harness the power of water to generate electricity.

According to the U.S. Geological Survey, the water cycle is a complex process that involves the movement of water between the atmosphere, land, and oceans. It is estimated that approximately 505,000 cubic kilometers of water is evaporated from the Earth’s surface each year, which is equivalent to about 505 trillion liters. This vast amount of water ensures that there is a constant supply available for hydroelectric power generation.

It does not produce greenhouse gas emissions

Another compelling argument in favor of hydroelectric power as a renewable energy source is that it does not produce greenhouse gas emissions. Unlike fossil fuels, which release carbon dioxide and other greenhouse gases when burned, hydroelectric power generation is a clean and environmentally friendly process.

The Intergovernmental Panel on Climate Change (IPCC) states that hydroelectric power is a low-carbon energy source that can help to mitigate climate change. According to their research, hydroelectric power plants do not emit significant amounts of carbon dioxide or other greenhouse gases during operation. This is in stark contrast to coal-fired power plants, which are a major source of global greenhouse gas emissions.

In addition to not producing greenhouse gas emissions during operation, hydroelectric power plants also have minimal impact on air quality. Unlike coal-fired power plants, which release pollutants such as sulfur dioxide and nitrogen oxides into the atmosphere, hydroelectric power generation does not contribute to air pollution.

Arguments Against Hydroelectric as Renewable

Dams impact fish populations and river ecosystems

While hydroelectric power is often touted as a renewable energy source, there are valid arguments against its classification as such. One of the main concerns is the impact of dams on fish populations and river ecosystems. Dams can block the natural migration routes of fish, hindering their ability to reproduce and threatening their populations. Additionally, the alteration of river flow caused by dam construction can disrupt the delicate balance of the ecosystem, leading to the loss of biodiversity and the degradation of habitats.

According to a report by the World Wildlife Fund (WWF), the construction of dams has resulted in the extinction of numerous fish species and the decline of others. For example, the iconic salmon population in the Pacific Northwest of the United States has significantly decreased due to the building of dams that obstruct their migration routes.

Furthermore, the formation of stagnant reservoirs behind dams can create favorable conditions for the growth of harmful algal blooms, which can have detrimental effects on aquatic life. These blooms can deplete oxygen levels in the water, leading to fish kills and the disruption of the food chain.

Reservoirs produce methane emissions

Another argument against hydroelectric power as a renewable energy source is the production of methane emissions from reservoirs. Methane is a potent greenhouse gas that contributes to climate change. When organic matter, such as vegetation and soil, is submerged in water, it decomposes anaerobically, producing methane.

A study conducted by researchers at the University of California, Davis, found that large reservoirs can produce significant amounts of methane. The study estimated that the total methane emissions from reservoirs globally were equivalent to approximately 1.3% of all human-caused greenhouse gas emissions. This highlights the potential environmental impact of hydroelectric power generation.

It is important to note that the extent of methane emissions varies depending on factors such as the size and age of the reservoir, the climate, and the management practices. However, the presence of methane emissions raises concerns about the overall environmental sustainability of hydroelectric power as a renewable energy source.

Assessing Hydroelectric’s Renewability

Weighing the pros and cons of hydroelectric

When discussing the renewability of hydroelectric power, it is important to consider both its advantages and disadvantages. On one hand, hydroelectric power is considered a renewable energy source because it relies on the natural flow of water, which is constantly replenished by the hydrological cycle. This means that as long as there is water flowing in rivers or streams, hydroelectric power can be generated. Additionally, hydroelectric power plants do not produce greenhouse gas emissions during operation, making it a cleaner alternative to fossil fuels.

On the other hand, there are some drawbacks to hydroelectric power that need to be considered. One concern is the environmental impact of building hydroelectric dams. Dams can disrupt the natural flow of rivers and affect ecosystems, leading to the displacement of wildlife and alteration of habitats. Additionally, the construction of large dams can require significant amounts of land, which may result in the loss of forests or other valuable natural areas. It is important to carefully assess these potential environmental impacts before implementing hydroelectric projects.

Considering hydroelectric’s renewability in context

While hydroelectric power is generally considered a renewable energy source, it is important to consider its renewability in the context of specific locations and circumstances. For example, the availability of water resources can vary depending on factors such as climate, rainfall patterns, and seasonal variations. In regions with limited water resources or where droughts are common, the reliability and sustainability of hydroelectric power may be compromised.

Furthermore, the lifespan of hydroelectric facilities should also be taken into account when assessing its renewability. While hydroelectric power plants can have long operational lives, the useful lifespan of a dam or turbine may vary. Regular maintenance and upgrades are necessary to ensure the continued efficiency and reliability of hydroelectric facilities. It is crucial to prioritize the development of sustainable practices and technologies to maximize the renewable potential of hydroelectric power.


In conclusion, while hydroelectric power relies on the renewable water cycle, its environmental impacts can be significant. Most experts consider hydroelectric to be a renewable source, but one that should be deployed thoughtfully and sustainably.

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