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Hydropower pros and cons

Last updated 9/27/2019

As with any energy source, renewable or non-renewable, hydropower has both pros and cons associated with its use. We’ll review some of the top benefits and drawbacks of hydropower technology.

Top pros and cons of hydropower

Hydropower has been the most widely-used renewable energy source of electricity for many years, and as with any energy choice, it comes with various advantages and disadvantages. Here are a few top ones to keep in mind:

Pros and cons of hydropower

Pros of hydropower Cons of hydropower
Renewable energy source Some adverse environmental impact
Pairs well with other renewables Expensive up-front
Can meet peak electricity demand Lack of available reservoirs

On the pros side, hydropower is a clean and renewable energy source that pairs well with other renewable energy technologies, and in some cases can be used to meet peak electricity demand. On the cons side, hydropower installations adversely impact the physical environment around them, are often expensive to build, and there are limited places remaining that are suitable for reservoirs and hydroelectric plants.

Below, we’ll explore these pros and cons in further detail.

pros and cons of hydropower infographic

Advantages of hydropower

Hydropower is clean and renewable

Unlike traditional fossil fuel energy sources, using water to generate electricity doesn’t release harmful pollutants into the air or water. While there are some environmental considerations that come with building large hydropower facilities like dams and reservoirs, once operational, hydropower plants themselves don’t require burning any fossil fuels.

Additionally, hydroelectric plants don’t use up water as they operate, making hydropower a completely renewable electricity source. As the water cycle naturally runs, hydropower will always be a viable way to generate electricity. Fossil fuels like coal and oil must be burned to generate power and replenish very slowly, and as such are not a long-term energy solution.

Hydropower pairs well with other renewables

The majority of hydroelectric plants are storage or pumped storage facilities that store large amounts of water in reservoirs, and will almost always have stored water to pull from to generate power. Hydropower’s reliance on stored water in reservoirs means that it is generally a reliable source of power in the sense that hydropower plants can be a stable source of supporting energy for more intermittent energy sources like wind and solar. Wind power and solar energy rely on the natural availability of wind and sunlight; just like an energy storage system, at times of low wind or at night when the sun isn’t shining, hydropower provides electricity when solar and wind can’t, making them more economical and practical sources of electricity.

Certain hydroelectric plant designs meet peak demand

A commonly cited drawback of many renewable energy sources (including wind and solar) is that they are non-dispatchable energy sources. This means that they can’t be used to generate electricity 24/7; instead, renewable sources like wind and solar rely on the wind to blow or the sun to shine respectively. However, both storage hydropower and pumped storage hydropower facilities have the ability to generate electricity on-demand (by releasing dammed water through turbines), making many hydroelectric plants dispatchable resources. This allows hydroelectricity plants to replace traditional dispatchable generation methods like coal and gas peaker plants.

Disadvantages of geothermal energy

Hydropower plants can adversely affect surrounding environments

While hydropower is a renewable energy source, there are some important environmental impacts that come along with building hydroelectric plants to be aware of. Most importantly, storage hydropower or pumped storage hydropower systems interrupt the natural flow of a river system. This leads to disrupted animal migration paths, issues with water quality, and human or wildlife displacement.

These negative environmental impacts of hydropower are typically lower with run-of-river, wave energy, or tidal power setups, but the vast majority of current hydropower systems are storage or pumped storage systems that block river flow.

Building hydropower facilities is expensive up-front

Many hydropower plants are large infrastructure projects that involve building a dam, a reservoir, and power-generating turbines. requiring a significant monetary investment. While a large hydropower facility can often provide low-cost electricity for 50 to 100 years after being built, the upfront construction costs can be large. This, combined with the fact that suitable places for reservoirs are becoming rarer over time means that large-scale hydropower plant construction costs may continue to rise.

Hydropower facilities rely on local hydrology

Hydropower is a reliable energy source, but it is still ultimately controlled by weather and precipitation trends. Because most hydropower generation relies on river water, droughts that cause lower water flow impact hydroelectric generation capacity. Month to month and year to year, the amount of water available for hydropower systems can vary, thus electricity production at a hydroelectric facility can also vary.

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