Hydropower Pros and Cons (and How it Works)

Hydropower (or electrical power generated from water sources) is the most widely-used source of renewable energy. But, what are the hydropower pros and cons?

Despite it offering numerous electricity-related advantages to consumers, there are several pros and cons of hydroelectric energy, with some of these being environmental. 

Learning the benefits and disadvantages of using hydropower is important if we are to make the right steps towards ensuring a sustainable world. In fact, hydropower is one of the remarkable examples of sustainable development.

In this article, I will explain in detail the hydropower pros and cons, and how this form of renewable energy works. Read along!

How Does Hydropower Work?

Also known as hydroelectric power, hydropower is a form of energy that generates power from moving water.

Usually, a dam or another diversion structure is created to change the natural flow of water, making it possible to use it to generate power. The hydropower plants then use the force of the water to spin the turbines, which are connected to an alternator to generate electricity.

Hydropower relies on the water cycle system to generate electricity. It uses water as its fuel; a source of energy that is neither reduced nor eliminated in the production process.

Hydroelectric power uses generators and turbines to convert the kinetic energy produced by the flowing water into electricity. Then, the electrical power is fed into the electrical grid, in turn powering homes, industries, and businesses.

What are the hydropower advantages and disadvantages? Let’s dive deeper into the hydropower pros and cons!

Hydropower pros and cons summary

Here’s a summary of the pros and cons of hydroelectric energy:

PROS ✅	CONS ❌
Eco friendly ?	Local Environmental Impact ?
Positive Social Impact ?	Requires large areas of land ?
Improves the local economy ?	May cause floods ?
Promotes sustainability ?	Not Always Safe ⚠
Renewable Resource ♻	It Relies on Local Hydrology ?
Flexible and works also at night ?	It Displaces People ?
Highly-Efficient ⚡	Expensive Upfront investment ?
Reliable ?	Lack of new suitable sites for a dam ?
Safe ?
Supports local irrigation ?
Low Operational Costs ?

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Now, let’s look at those hydropower advantages and disadvantages more in detail.

Pros of Hydroelectric Energy

The following are the main advantages of hydropower:

1. Eco friendly

Hydroelectric power is one of the most environmental-friendly sources of energy on Earth. While running it does not involve the use of any fossil fuels or non renewable resources. So it does not release any harmful emissions into the air, water, and the environment, causing pollution.

This renewable source of energy can provide a constant supply of clean energy.

While dams, reservoirs and other diversion structures created may have a negative impact on the environment, they only cause pollution during the initial construction. After these have been fully built and established, they do not have any additional impact on the environment. This is because the hydropower plants do not require the burning of fossil fuels to operate, contrary to oil and coal which must be burned to produce power.

Besides, the production process of hydropower energy does not release carbon or other greenhouse gas emissions.

This is what makes hydroelectric power one of the great examples of environmental sustainability and also one of the best examples of green technology.

Also, the plants do not use up water for their operational processes. The water cycle runs naturally, making hydroelectric power a viable and environmentally sustainable source of energy. 

2. Positive Social Impact

Most dams are created to get a reservoir of water. These dams and reservoirs provide more than just energy independence; they also improve the quality of life of the local community. How so? 

Reservoirs are man-made lakes that can accommodate several additional activities, such as swimming, fishing, windsurfing, and boating, just to mention a few. These numerous activities supported by the reservoir construction are improving social sustainability, by creating new opportunities to connect and socialize.

Also, hydroelectric power plants supply electricity to numerous communities, including those in remote regions. This leads to the development of new communities and the improvement of existing ones.

3. Improves the local economy

The numerous activities that can flourish around an artificial lake acting as a reservoir for hydropower can also bring significant profits to the local economy. This creates new jobs and boosts the economic sustainability of the area. 

Hydroelectric plants can generate large amounts of cheap and clean energy that can attract different industries, encourage the construction of highways, and boost commerce. 

4. Promotes sustainability

What’s even better, hydropower promotes sustainable development. Not only does it ensure energy independence now, but it does not also affect the ability of future generations to cater to their energy needs.

Hydroelectric power is simply the type of energy that helps us work towards attaining true sustainability by leveraging all of its 3 pillars (3 Ps of sustainability), also known as the 3 E’s of sustainable development: economy, ecology, and equity.

5. Renewable Resource

The main source of fuel for hydropower is water. Water is everywhere; and while drinking water may be hard to find, you can rest assured that the earth will never run out of water.

The fact that water is a renewable source of energy that never runs out makes hydropower a reliable and stable form of renewable energy.

Also, hydroelectric power promotes energy independence among different countries, making it a great resource.

It reduces the demand for external sources of fossil fuels, in turn helping to reduce conflicts in the regions where they are extracted. And by becoming energy-independent, these countries are also able to improve their economic issues by ensuring a constant supply of affordable and clean, domestic energy.

6. Flexible and works also at night

Coal, wind, and solar energies tend to fluctuate from to time, this is because they are intermittent by their own nature.

On the other hand, hydropower is constant, since it relies on a constant and stable source of water. What’s even better, hydroelectric energy is flexible; the flow of water can be altered easily to meet all the supply needs. 

In other words, hydropower makes it possible to supply electricity only when it is needed, even during the night. This ensures that electricity is only supplied when the need arises, minimizing the wastage of precious energy.

7. Highly-Efficient

Hydroelectric power has a higher energy efficiency compared to most other renewable sources of energy and fossil fuels.

For example, wind power has a maximum energy efficiency of 20-40%, coal power has an average of 33% efficiency in the US, and solar power has a maximum of 15-22% efficiency. On the other hand, hydro energy converted water into electricity at a maximum efficiency of 90%.

Indeed, all other forms of energy pale in comparison to hydroelectric power efficiency.

8. Reliable

In addition, hydropower has very little to no downtime, making it a very reliable form of renewable energy.

This is because water flow in the dams is generally only stopped for a short while, say for maintenance, repairs, or upgrades. Otherwise, water flows continuously, providing a steady supply of hydropower.

This is contrary to wind power which only works when there are strong winds blowing or solar power which, despite its benefits to the environment, decreases in production during cloudy days or when the sun goes down. 

9. Safe

Dams, reservoirs, and the general production of hydroelectric power are fairly safe. On the other hand, most other forms of energy pose huge risks during the production process.

For example, mining coal and uranium (which is used for the production of nuclear energy) may release harmful emissions to the environment, risking the health and lives of any people, animals, and organisms living nearby. This is also because open pit mining is so devastating to the environment and, unfortunately, this is the way we can use to extract natural resources that are close to the ground surface.

On the other hand, the construction of dams is usually safe, and as for the rare accidents that happen in hydropower plants, these are usually caused by poor construction and the failure to uphold safety standards, especially in order dams. 

10. Supports local irrigation

Providing hydroelectric power is not the only use for these power plants and dams: they can also be used as a source of water for irrigation.

These dams can especially prove beneficial in areas where droughts are common and rainy seasons are rare.

In these areas, the hydropower reservoirs provide a reliable and constant source of fresh water for irrigating crops throughout the year.

11. Low Operational Costs

It is true that building hydropower plants can be very costly. However, once the hydroelectric dam or reservoir is fully operational and the infrastructure is up and running, maintaining it is relatively cheap. In fact, hydropower is ranked among the most cost-effective forms of energy available. 

Unlike imported fuels and traditional fossil fuels that tend to fluctuate in cost, water accumulation costs do not fluctuate, because they only depend on the natural cycles of the planet.

After all, the water cycle through the turbines can be easily managed and kept constant. The operation process does not use up any water, which could lead to depletion. Therefore, countries that use hydropower heavily, such as Paraguay, save a lot of money by simply using hydroelectric power.

Cons of Hydroelectric Energy

Despite all the advantages that hydropower has to offer, this renewable form of energy also has its flip side. Consider these 5 main cons associated with hydroelectric energy!

1. Local Environmental Impact

The biggest disadvantage of hydropower is its negative effect on the local environment and ecosystems. The major environmental impact is caused by the construction of the hydropower plant, especially the construction of the dam. This usually has a significant impact on the upstream and downstream flow of the water. 

When the flow of water is blocked, it significantly impacts fish migration. In fact, dams and reservoirs can even impact the biological triggers of fish; natural instincts that tell them when to migrate and where to go.

Fortunately, most hydropower plants and dams are now creating fish elevators and ladders that help migratory fish species to travel to their spawning grounds.

Also, when building dams and reservoirs, several power lines connecting the power plants must be installed and new roads constructed. All these new constructions disrupt the environment.

2. Requires large areas of land

Hydropower plants take up large areas of land, which means disrupting natural habitats and sometimes displacing thousands of people for these to be built.

Just consider all the land occupied by the artificial lake as well as the entire infrastructure of the power plant: it’s huge compared to other solutions.

3. May cause floods

Dams may flood areas, creating different sections of stagnant water.

Stagnant water is breeding some bacteria, mosquitoes, and, eventually, cholera. Diseases that pose serious health risks to people.

Stagnant water kills any growing vegetation, which eventually rots and releases harmful greenhouse gases.

4. Not Always Safe

While hydropower plants are considered generally safe, it does not mean that accidents never happen. Sometimes, dam failure and construction accidents happen, leading to injuries or even death.

A good example of this is the Hoover Dam, where 112 people died during its construction.

Also, dams and reservoirs pose a great risk for floods, especially when strong currents of water are released.

These floods can cause the death of people living at lower elevations, while thousands more could be displaced and their lives permanently altered.

Thankfully, hydropower plants are now being built with higher safety standards, reducing the occurrence of such dam fails and accidents.

5. It Relies on Local Hydrology

Hydropower is considered a stable source of energy. However, it is dependent on weather and precipitation trends that might be affected by climatic changes. For example, in the instance of drought, the level of water in the dam may drop, negatively impacting the generation of hydroelectric power.

In addition, due to fluctuating weather conditions and changing seasons, the amount of water in the dams may vary from time to time.

The fluctuating water levels can lead to varying production of electricity at the hydroelectric facilities.

When water levels fall below normal, energy production at the sites may not be enough to meet all the needs of the community.

6. It Displaces People

The construction of hydropower plants leads to the displacement of both animals and people. Humans who have lived in a particular place their entire lives may be forced to move from their homes.

In fact, entire towns, villages, and cities have been completely eliminated and local cultures erased simply due to the construction of dams. And even though the government usually compensates people for their moves, the truth is that the compensation can never make up for what they lose.

Sometimes, people refuse to move from their homes to allow for the construction of dams. Yet, the result is always negative, since they are forced out with threats of violence. For example, during the building of the Chixoy Dam in Guatemala, many Mayans were killed simply because they refused to move out as had been ordered. 

An iconic example of this is the submerged village in Lake Resia (Italy). The village was submerged due to the construction of a dam for a hydroelectric power plant. Still to this day, it is possible to admire the old bell tower of the village’s church rising from the water in the middle of the artificial lake.

7. Expensive Upfront investment

While operating hydropower facilities is relatively cheap, building them is quite expensive. The process of building dams, reservoirs, and installing power-generating turbines requires high upfront costs.

Finally, the construction of dams does not always take the estimated time. While some hydropower plants take 2-5 years to build, others take even longer.

Such delays only lead to increased costs and overspending. Costs that might never be re-acquired even after constructing the dam.

8. Lack of new suitable sites for a dam

In addition, suitable places for building reservoirs and hydropower plants are becoming rarer, leading to increasing costs for constructing large-scale hydropower plants.

This is because hydroelectric power was one of the first renewable sources of energy to be tapped into by humans. So there aren’t many additional locations suitable to build hydropower plants in the world.

Luckily, new green technology is helping us to find new ways to use hydroelectric power also in places where this was not possible before!

Better hydropower solutions are now available

Luckily, some great green technology companies are developing a new generation of micro hydropower plants that don’t require a dam and have a much lower environmental impact!

Those are micro-hydropower plants that can be easily installed along rivers with minimum infrastructure work required.

Moreover, those new generations of turbines can also be installed along low-head rivers, dramatically increasing the available location for hydropower installations!

The benefits of green technology in the hydroelectric sector are very good news to reduce our environmental footprint and switch to a more decentralized power grid.

Conclusion

Water is the main source of life; all organisms need it to survive, but it can also be used to produce electricity. So much so that hydropower accounts for approximately 16% of the total electricity production in the world! 

Undoubtedly, hydropower is a better energy solution for the Earth. Not only does hydroelectric power promote environmental sustainability, but it also encourages economic sustainability, improving the quality of life for most people and fulfilling the 4 pillars of sustainability.

Even so, this form of energy has several disadvantages, especially for the local ecosystems.

Here are the hydropower pros and cons:

Studying these pros and cons of hydroelectric energy as well as of other sources like nuclear energy can help make informed decisions on how to create sustainable energy solutions, now and in the future!

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