Advantages and Disadvantages of Hydroelectric Energy

03/07/2022

Compared with solar energy, hydroelectric energy is also an environmental resource. More and more places start to use this kind of resource to produce electric power to satisfy their daily needs. Hydroelectric energy is electricity generated through the movement of running water. This can be from a flowing river, or a dammed reservoir. Generally speaking, the most widely used form of hydroelectricity is from power plants housed in a dam. One example is of course the Great Hoover Dam, which you may be familiar with.

To produce electricity, all hydropower plants follow roughly the same steps. The water is funnelled in through a channel (or channels) where its flow rotates a turbine. The turbine in turn powers a generator, and then the electricity produced by the generator enters the supply line.

These days, hydroelectric energy is an important component of the energy supplies of most major countries due to its reliability and advantages over fossil fuels. In this article we’re going to take a look at some of these advantages, but also the disadvantages of hydropower. We’ll also take a look at the pros and cons of small hydro plants.

Is Hydroelectric Energy Renewable?

Unlike fossil fuels which are finite, hydroelectricity is considered a renewable energy source. This is because hydroelectric plants generate energy by harnessing the kinetic (associated with movement) power of flowing water. Given that water is naturally occurring, and not combusted during the process, we can say that it is a renewable resource.

What Are 5 Advantages of Hydroelectric Power?


As we’ve just discussed, hydropower is renewable and does not rely on combustion.

Dams and their reservoirs hold predictable amounts of water according to the time of year.
Modern engineering means Dams are now incredibly safe, no matter their size.

Hydropower plants can be made to various scales and on rivers with varying volumes. Power generation can also be regulated up or down.

Low emission generation. Any emissions generated by hydroelectric plants are from associated machinery and only a fraction of those generated by fossil fuel plants.

Though important, these aren’t the only advantages to this type of power. Others include improved irrigation, tourism generation, and flood control.

Which Power Plant Is Most Reliable?

The most reliable power plant that uses non-renewable energy sources is the nuclear power plant. But as might expect, there are serious environmental and safety concerns associated with this type of power.

Amongst the power plants that use renewable energy, hydroelectric and geothermal plants are the most reliable. In fact, hydroelectric plants are more reliable than either solar installations, like solar panel installation or wind farms.

The reason for this is that the reserves of water in a hydroelectric reservoir, or even a whole river system, generally take months to deplete from low rainfall. Even a short-lived drought is unlikely to interrupt power supply. Sunshine and wind, on the other hand, can vanish over the course of a few minutes.

What Are the Disadvantages of Hydroelectric Power?

The main disadvantage of hydropower is that the initial environmental impact can be very high. Flooding damage, and the interruption of migration routes for fish can have a lasting impact on the local ecosystem. Fish ladders, and other mitigation measures are almost always necessary.

Moreover, the impact on local communities can be high. Displacement and flooding can uproot whole communities. Those that rely on fishing can be particularly hard hit.

In monetary terms, hydro dams are also very expensive to build. This is partly down to the red tape involved, which often includes legal opposition from the displaced communities mentioned above. Another reason is the skilled workforce and raw materials required to construct them. It doesn’t end there though – some dam reservoirs also need dredging which is also costly.

Another often overlooked disadvantage is that some areas that are flooded to build hydropower plants are “carbon sinks”. This means forests, bogs or other ecosystems that hold a lot of carbon in organic matter. When they are flooded, this matter decays and releases the carbon into the atmosphere.

What Are the Advantages and Disadvantages of Small Hydropower Plants?

Sometimes called Micro Hydropower Plants (MHP). Small hydropower plants are versatile installations which can be used anywhere there is running or dammed water. In some cases, they can even be installed on private property which includes running water.

Most small hydroelectric installations generate from 10 to 100 Kw per hour of usage at maximum power output. Due to their small size, they can be used on small rivers, streams and even along water supply lines – eliminating the need for large dams.

Their two main advantages are that they cost much less to build, and they have a much lower environmental and community impact.

Nonetheless, small hydropower does have disadvantages. The most important is of course that they cannot generate anyway near as much electricity as a traditional hydropower plant. Overall, they are very much for the individual of very small community.

Reliability is also an issue with this type of installation. If an installation relies on a small lake or stream, then a drought can completely halt electricity production.