Renewable sources of energy play a crucial role in our fight against climate change. Switching to cleaner energy sources reduces our reliance on fossil fuels and can drastically reduce global greenhouse gas emissions.

When it comes to renewable energy, there are three big sources: wind, solar, and hydropower, also known as hydroelectric power. Geothermal is also another clean and renewable source of clean energy, but it is deployed to a lesser extent around the world. Though significantly better for the environment than traditional sources of electricity, any clean energy source still has environmental impacts.

In this article, we will explain the environmental impacts of the hydropower industry and how hydroelectric plants can mitigate some of them to provide the benefits of hydropower while minimizing the environmental impact of hydroelectric facilities.

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How Do Hydroelectric Power Plants Generate Electricity?

Whereas wind energy plants generate power by harnessing the wind and solar energy plants generate energy from the sun, hydropower plants generate electricity from natural water cycles, mainly rivers.

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Wind vs solar vs hydropower facilities:

• Wind energy facilities leverage wind to spin turbines to generate renewable energy
• Solar energy facilities convert solar energy to stored energy to generate renewable electricity
• Hydroelectric power facilities use dams to generate renewable electricity

In order to generate energy, a hydropower plant blocks the natural flow of water using a dam. As water runs through the hydropower dam in a controlled flow, it pushes blades in a turbine, turning them to create electricity generation.

In other words, the kinetic energy of flowing water is mechanically converted into electric energy that can be used and stored as needed. 

All the water stored behind hydropower dams is known as hydropower reservoirs. The dams can control the flow of this water to generate more or less energy depending on downstream needs.

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Benefits of hydropower

• As long as there are natural water cycles, hydropower is a renewable energy source
• Does not pollute the air, as coal or natural gas plants do when they burn fuel
• Hydropower doesn’t have to be imported — can harness local water sources
• Reservoir water can be used for other purposes, such as fishing and recreational opportunities
• Hydropower facilities can provide valuable backup energy very quickly
• Can provide flood control, irrigation, and drinking water
• Hydropower is cost effective and can be used with other renewable sources of energy

As you can see from the above list, hydropower has a lot of potential benefits, one of the biggest being that most hydroelectric power plants don’t emit greenhouse gases like traditional electricity generation facilities that burn fossil fuels.

Even though construction of a dam area can generate greenhouse gas emissions, the long life of hydroelectric power plants typically more than offsets the carbon footprint of their construction.

However, as we touched on a little earlier, hydropower facilities can still have negative environmental impacts in areas other than greenhouse gas emissions. Though they may not contribute directly to global warming, it’s important not to overlook these potential problems.

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What Are the Environmental Impacts of Hydropower?

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Despite all the benefits of hydropower and the fact that it is a less carbon-intensive than forms of energy creation based on fossil fuels, hydro facilities present their own unique challenges.

Carbon dioxide and methane form in reservoirs

Even though hydro facilities don’t have strong greenhouse gas emissions themselves, the reservoirs created by dams can generate carbon dioxide emissions and methane emissions.

A certain amount of these types of greenhouse gas emissions occur in every aquatic environment. This occurs because of the decomposition of biomass (from aquatic plants and animals) in the water.

However, since reservoirs are not natural water formations, the levels of carbon dioxide emissions and methane emissions in them may be higher than what is found in natural aquatic environments. 

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Dams obstruct fish migration

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Another big environmental risk presented by building dams is that they can obstruct fish migration up and downstream. 

Many types of fish return to their spawning grounds upstream to lay their eggs and they can’t get there if there is a dam blocking their way. 

This is especially true of salmon, who return to their original spawning grounds on the gravel beds of the upper reaches of rivers year after year. 

Unless they take special measures to help fish reach their spawning grounds (especially salmon), building dams can devastate native fish populations. This is not only because the fish are unable to spawn, but because many helplessly attempt to find a way through the dam and die before they are able to reach their natural spawning grounds.

Fish are a critical part of the food ladder. As natural fish migration declines precipitously other animals up and down the food ladder are impacted significantly.

Fortunately, many dam facilities are implementing fish ladders to help fish continue their natural migrations upstream to their spawning grounds. Fish ladders are basically stairs with running water that give migrating fish a natural path to continue their way upstream, avoiding a dam and its dangerous turbines.

By building dams with fish ladders, hydropower facility operators can begin to mitigate one of the biggest environmental impacts of hydroelectric energy plants and ensure salmon and other fish are able to reach their spawning grounds.

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Dams change a river’s flow

Other environmental impacts that a hydropower energy plant can have are due to the fact that it’s dam changes the natural flow of a river. 

This can harm native plants and destroy natural habitats, as well as displace communities who rely on the water for drinking or irrigating agricultural land. Widespread dams have led to desertification of some areas or complete change of natural landscape in others. 

It should be noted that the people disproportionately affected by hydroelectric power plant construction are already marginalized communities, which creates social issues in addition to environmental ones. 

In the US, specifically, indigenous communities are the most often displaced or negatively affected by reservoir and dam construction. There are also numerous instances in which dams have caused flooding of archeological sites and important natural areas.  

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Is Hydropower Worth It?

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Ultimately, any renewable source of electricity is better than traditional sources that burn fossil fuels and generate high levels of greenhouse gas emissions.

Whether it’s wind, solar, or hydro, it’s important to be aware of the potential impacts even a clean source of energy can have.

Being a domestic source of electricity that doesn’t burn fossil fuel and allows local populations to generate green electricity locally, hydropower and reservoirs are a very attractive option for renewable electrical power. 

But, it’s important to be aware of the potentially large environmental impacts hydropower facility construction can have in order to minimize the negative impacts, especially on local wildlife important natural areas.

With proper studies and planning, the environmental impacts hydropower can have can be mitigated to ensure facility construction isn’t negatively affecting land use (especially agricultural land use), harming native plants, destroying wildlife habitats, or displacing local communities.

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Atmos only supports socially responsible green electricity initiatives

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At Atmos Financial, our mission is to finance the rapid transition to the clean economy for all. 

When you deposit your money with Atmos, it helps finance climate-positive projects that reduce carbon emissions — but we will never support clean energy projects that displace communities or harm the natural landscape.

Contact Atmos for more information about how you can make a positive environmental impact today.