What is hydroelectric power?

Hydropower is any kind of usable energy that comes from water, which can be from a variety of sources, including turbines and dams. This is one of the most widely-used sources of renewable energy for electricity generation, and has been for years.

We most often see hydropower generated from reservoirs and dams, but it can also come from run-of-river, wave, and tidal power systems. For the purposes of this article, we’ll focus mostly on hydroelectric facilities rather than wave and tidal power, but all of these systems can be used to create consumable electricity to power homes and businesses.

Let’s take a closer look at the most common forms of hydroelectric power generation.

1. Conventional hydroelectric dams

A hydroelectric dam is the image most people have in mind when they think about hydropower, for good reason. This has long been the most common type of energy generation from water, with famous examples including the Hoover Dam.

Conventional hydroelectric dams have a large reservoir of water, which is why they’re often called storage or impoundment systems. Water pressure builds up behind the dam, and is designed to be released or held when needed to generate electricity, manage flow and water levels, or help with fish passage.

When the dam releases water from the reservoir, it flows through a turbine, making it turn, and as it does it activates a generator which produces electricity.

2. Pumped storage

Pumped storage hydropower, or PSH, functions rather like a battery for other power sources, such as solar, wind, or nuclear. The PSH system stores the energy generated from these other power sources, by pumping the water from a reservoir to another one at a higher elevation.

This energy can then be released when needed by letting the water flow back to the lower reservoir and turning a turbine as it does, generating electricity. This form of hydropower is most useful when used to fill the gaps during times of high demand.

3. Run-of-the-river

Run-of-the-river, also known as diversion facilities rely on a consistent supply of water coming from a lake, river, or reservoir. The system diverts a part of the water flow and sends it through a canal or penstock, taking advantage of the natural slope and flow of the river to turn a turbine and generate electricity.

This kind of system may or may not incorporate a dam, but the water flow is always regulated through a system of gates, valves, and turbines.

4. Tidal energy

Tidal energy, tide energy, or wave energy, relies solely on the rise and fall of the tide in the ocean. This is a clean, renewable form of energy, but can only be harvested in very specific locations, so is not viable for all countries and states.

Read more about tidal wave energy in our featured post.

Despite being driven by water, hydroelectric power plants actually produce electricity in a very similar way to coal power plants, making knowledge and technology easily transferable.

Both types of facilities rely on propeller-based turbines to generate power. While in hydroelectric plants the turbines are turned by water, steam turns the turbines in a coal power plant.

Pros of hydroelectric power

Hydroelectric power is a truly renewable type of energy, which doesn’t rely on a consumable feedstock, unlike biomass. This is just one of the advantages of using it to generate electricity, which we’ll look at next.

1. It’s a clean, renewable source of energy

Hydropower is a cleaner, renewable alternative to fossil fuels. Much of the world still relies on coal and natural gas to power their homes, but these sources of energy won’t last forever, with scientists predicting known reserves of both will run out this century at our current rate of use.

Water, on the other hand, is a renewable source of energy: as long as it continues to flow, we’ll be able to use it to generate energy, without using up the water itself.

Furthermore, fossil fuels generate greenhouse gas emissions as well as other forms of pollution. It should be acknowledged that hydroelectric facilities usually involve fossil fuels and other environmental impacts to build, but once constructed, they don’t cause water or air pollution.

2. Low installation and operating costs

Despite a significant initial investment, hydroelectric power is one of the lowest-cost types of renewable energy over the long term.

After building the infrastructure, very little maintenance is needed over time and running costs are much more affordable than other types of electricity generation. The return on the investment lasts for a long time, with hydroelectric dams and power plants easily lasting more than a century.

Furthermore, hydropower technology is continuously being developed and advanced, becoming ever more efficient and cost-effective.

3. It uses simple, understandable technology

Another advantage of hydroelectric systems is that as well as being affordable to run, they’re also relatively simple. For this reason, facilities are being built and successfully run in countries all over the world.

Furthermore, because hydropower plants operate in a very similar way to coal power plants, as coal is phased out, it will be relatively easy for workers to transition to the hydro industry.

4. It’s flexible

Hydro energy can easily be turned on and off to meet demand or as river flows change, with a limited operating expense. It’s also possible to shut off the system without affecting its overall performance.

Equally, hydroelectric power facilities can be ramped up very quickly once flows are at peak levels or to supplement other sources of energy and typically have high capacities.

5. It can be used with other renewables

Hydroelectric is also ideal for pairing with other forms of renewable energy. Because most hydropower facilities incorporate reservoirs that store large bodies of water, they can provide a stable source of energy to supplement less reliable renewables such as wind or solar.

Furthermore, most hydroelectric facilities are designed to gear up from zero to maximum power output virtually instantly, unlike many other types of electricity generation. Therefore, they can immediately feed power into the grid when required and cover power disruptions or outtages.

In other words, hydropower can fill in the gaps when the sun doesn’t shine or there isn’t enough wind to generate enough power. This helps to address one of the most common concerns around renewable energy.

6. It’s made in the USA

Many types of electricity generation technology, both renewable and non-renewable, come from overseas. However, hydroelectric power is made entirely in the USA, supporting local jobs, particularly in rural communities, and minimizing the emissions associated with transporting the tools and infrastructure.

Currently, the hydropower industry in the USA employs more than 66,000 people and the growing industry is predicted to expand to 120,000 jobs by 2030, not only in direct hydroelectric generation, but also manufacturing, construction, transportation, water management, environmental science, and professional services.

Furthermore, the water itself comes from domestic sources, so every state can generate its own power that doesn’t rely on international sources of fuel.

7. Hydropower facilities support other uses

Hydropower facilities can serve multiple purposes: not only can they harvest the power of water and convert into energy, but they can also supply water for irrigation. With water shortages and drought on the rise in many areas, this can be a very useful way to supply vital water to crops or drinking water to local towns.

In some cases, hydropower systems can assist with flood control, and so play a vital role in protecting humans and animals alike.

Hydropower reservoirs can also provide recreational opportunities to local communities, such as boating, fishing, and swimming. In fact, local authorities usually require hydroelectric companies to allow the public to access and enjoy the reservoir.

Cons of hydroelectric power

Despite its benefits, hydroelectric power also has its downsides. It’s important to be aware of these considerations when balancing the advantages of this kind of renewable energy.

1. It can have negative environmental impacts

While hydropower is a generally clean, renewable source of energy, this doesn’t mean it’s always good for the environment.

Most hydroelectric facilities rely on storage hydropower or pumped storage hydropower systems, that is, reservoirs made by dykes or dams. These are formed by disrupting natural river systems that can disturb wildlife, destroy habitats, and threaten water quality.

However, there are other forms of hydropower that have a lower environmental impact, notably run-of-river, wave, and tidal power systems, though these are currently the minority of hydroelectric plants.

2. It can impact on people too

Damming rivers and creating reservoirs can have negative impacts not only on wildlife and their habitats, but also humans. People may be forced to leave their homes to make way for hydroelectric systems, and this most commonly affects rural and indigenous communities.

Despite the compensation usually offered, this can have incredible impacts on not only the individuals involved, but also local cultures going back generations.

In some countries, people may even be forced to move under threat of violence. In 1982, 444 Mayans, mostly women and children, were reportedly killed because they refused to move to make way for the Chixoy dam.

Furthermore, it’s not just the communities who live in projected reservoir areas that can be disrupted. Hydroelectric facilities can increase the risk of flooding downstream, potentially putting people living in these areas at risk.

3. Large upfront investment

Although being cheap to run once established, building a hydropower plant is a huge, costly project. Establishing a hydroelectricity facility involves not only building power-generating turbines and their associated power plant, but also other infrastructure such as a dam and reservoir in the case of storage hydropower.

Furthermore, the cost of building such facilities is only set to increase in the future as suitable sites are used and therefore becoming more scarce.

4. Risk of large-scale failure

All dams involve risks such as construction accidents, dam failure, and flooding. Storage hydropower facilities can have huge volumes of water in their reservoirs, which could cause devastating destruction if things go wrong.

At least 96 people died as part of building the Hoover Dam, and when the China’s Banqiao Reservoir Dam was destroyed in a typhoon in 1975, it failed causing the deaths of more than 150,000 people.

Although modern dams are built to much higher safety standards and well-maintained to make them as safe as possible, some risks still remain.

5. Water is becoming increasingly scarce

Although water is a renewable resource, there are concerns over its supply. Globally, we’re seeing a downturn in the amount of water available.

If rainfall drops enough and droughts become severe, low water flows could make hydroelectric facilities less efficient and could even stop being viable entirely.

Furthermore, running a hydroelectric facility usually involves some degree of water loss. Although this is a very small proportion of the overall water used, it’s important to consider this loss given the global water crisis.

6. There are limited sites for storage hydroelectric facilities

While water is largely unlimited, there is a limit on the locations suitable for hydroelectric facilities, or more specifically, storage hydro plants with reservoir dams. Hydroelectric dams have very specific requirements and can only be built on certain sites.

It’s important to find a location that can not only support a hydroelectric dam, but will also turn enough profit to justify the investment to build the facility.

Final thoughts

The pros and cons of hydroelectric power paint a complex picture. This is a clean, renewable, and largely environmentally-friendly way to generate electricity, but it can also have negative impacts on people and the planet.

As we look to move away from non-renewable, polluting, and dangerous fossil fuels like coal and natural gas, it’s important to take a considered view of the alternatives. By acknowledging the drawbacks and managing the risks associated with hydropower, we can come up with the best solutions for the future.

Hydropower facilities from an investment standpoint as they are straightforward, proven and relatively predictable. Perhaps the answer lies in using hydroelectric power plants in coordination with other renewables like wind and solar.

Learn more about the future of renewable energy with our guides to solar, wind, geothermal, and biomass. Or check out our post about the pros and cons of sea wall.

Pros and Cons about Tidal Wave Energy

Every day, innovators recognize the essence to capture clean energy from renewable sources. One of the latest revolutions is the capture of green energy from the oceanic tides and waves.

In this article, we will discuss some of the basic facts about tidal wave energy as well as the many tidal wave energy pros and cons.

Throughout the world, there is a growing drive to create green energy from renewable sources to replace the non-renewable energy sources that are not only depleting but pose a threat to the environment.

Tidal wave energy which is one of the least advanced yet holds the most potential clean, eco-friendly energy is still in its infancy stages.

So what is tidal wave energy?

Tidal wave energy is the power produced by the waves and tides. It is a form of hydroelectric power. Special buoys, turbines, and other tidal energy generators capture the tidal wave energy and convert it into clean, pollution-free electricity.

Girard and son patented the first idea about wave technologies in 1799 in France.

Interesting facts about tidal wave energy

Before we dive into the details of tidal wave energy pros and cons, let’s have a look at some interesting facts about tidal wave energy.

• A phenomenon fact about wave energy is that if winds blow across the surface of the ocean, they produce waves which are then converted to energy. Underwater turbines are placed in areas where there is a high level of tidal movements to capture the kinetic motions of the surging and ebbing of the oceanic tides. When the energy is obtained, it is converted into clean energy.
• The tidal wave energy plants can be set up in three different points in the ocean or sea to capture the wave energy which includes: nearshore, offshore and far offshore.
• Tidal wave energy is that it can be obtained either from lower in the sea from the pressure changes or at the surface of the sea from waves.
• The kilowatts (kW) per meter of coastline in the city or the country are used to measure the potential of wave energy in an area or a country.
• Another remarkable fact about ocean energy is that oceanic waves have the highest energy density compared to all the other alternative sources of energy.
• A technology that converts wave power into electricity is called Wave Dragon, and the name of another wave energy converter is Oyster.
• A process called Influx of energy is used to utilize the power from the sea waves.

Without much further ado, let’s now look at the numerous tidal wave energy pros and cons.

Tidal wave energy pros and cons

In order to understand the true components of tidal energy, we need to evaluate both the pros and cons about tidal wave energy.

Pros of tidal wave energy

Below are the many advantages of using tidal wave energy.

It is truly a renewable source of energy

One of the significant advantages of tidal wave energy is that it is renewable. It is no brainer that the oceanic tides and waves used to generate the tidal wave power occurs naturally.  The oceanic tides and waves are as a result of the effects of the rotation of the earth on its axis, combined with the gravitational force of the sun and the moon.

Tidal wave energy thus becomes an Infinite source of energy since those effects will always be there.

It remains environmentally friendly

Tidal power is one of the most eco-friendly sources of energy since it does not emit any harmful gases like carbon, residues or other greenhouse gases to the environment unlike other sources of energy like nuclear energy or fossil energy.

The tidal wave energy can be taken directly from the tides and waves and made directly to the production of electricity that is used to power the generators of the plant.

It is more reliable than other sources of energy

Since the tides, which can be low or high, occur in certain cycles and times, it is easier to predict their occurrences and plan well before to get the amount of power required. An interesting fact about tidal wave energy is that tides and waves are almost always in motion and less interrupted unlike the other sources like solar and wind.

So, tidal wave energy is a more reliable source of energy since it is certain the tides and waves will be there for almost the entire year. Thus, this usually results in a higher capacity factor relative to other renewables.

It is more effective than any other alternative energy

Another advantage of tidal wave energy is that it’s more effective than other alternative sources of energy since water is denser than air; it makes it easier to generate the electricity required, even at very low speeds of water.

Calculations reveal that power can be produced even at a speed rate of as little as 1m/s which are equal to slightly above 3fts/s.

Cost competitive

Since the source of tidal wave energy is not deemed to diminish in any near future, the power plants producing this kind of energy can sell the electricity at relatively lower prices

Massive power potential

These tides and waves have the potential to generate an enormous amount of tidal energy since the amount of power that comes with these tides are considerable.

Typically, for every meter of wave around the shore, the energy density that comes with it is around 40KW, and if going deeper into the ocean, the same length of the wave produces around 100KW. Tidal wave energy would have an interesting capacity factor profile. 

Offshore wave power

Ocean wave energy plants can be constructed way deep into the ocean and far from the shore. It helps solve the issues that can arise if these processing plants are set up near the beach. 

It also means that there will be more power potential for the plant since when it’s more in-depth into the sea, the tides can produce much more energy compared to near the land.

Abundant and readily available

One among the many facts about ocean energy is that it is readily available and in abundance. Many of the big cities and harbors in the world are near the ocean lines thus can efficiently harness the tidal wave power. Oceans cover the most substantial part of the earth thus making the wave energy so much available.

See Related: Pros and Cons of Nuclear Energy

Cons about tidal wave energy

Below are some of the most important disadvantages of tidal wave energy.

Costs

The initial cost of setting up and operating a tidal wave power plant is very high. It makes the tidal wave power relatively expensive at the moment though it’s expected that this will significantly drop with time. Tidal wave energy is still in its very early stages of developing and acceptance globally, and thus it’s hard to predict the exact costs of setting up the plants.

Effects on tourism and high-demand land

While tidal wave energy is environmentally friendly, tidal wave power plants that are near the shores may cause conflicts with tourism and also the acceptance by the local community. It, in turn, attracts more restrictions regarding size and location when constructing a plant along the coastline or near the shores. Maintenance of the machines used in the tidal wave power production may also be a challenge since they are underwater making it challenging and expensive.

Let’s be honest everyone loves the shoreline. It doesn’t need even need a sunny beach to be beautiful.

See Related: Sea Wall Advantages and Disadvantages

Effect on marine ecosystem

Although the oceanic wave energy is one of the cleanest kinds of power, it still has some impact on the creatures living nearby. For example, large machinery has effects on the natural order of the sea living beings since it disturbs the seafloor and may cause some of the animals to change their habitats.

If chemicals are used in the process of harnessing the tidal energy, it may spill and cause harm to the environment.

Limited to certain locations

Location is the most notable limitation to getting your energy from the tidal wave power generating plants since only the cities around the oceans can access this kind of power. Countries which are landlocked may not also benefit from tidal wave energy.

It makes the oceanic wave energy not the most viable source for everyone.

See Related: Pros and Cons of Nonrenewable Energy

Conclusion on the Pros and Cons about Tidal Wave Energy

After analyzing tidal wave energy pros and cons, it is evident that the tidal wave has the most potential for producing green and clean energy for the humankind in the future. I hope this article has offered valuable insights on tidal wave energy pros and cons.

What do you think about the pros and cons about tidal wave energy? We’d love to hear from you!

Other Renewable Energy Resources:

• Advantages of Photovoltaic Cells
• Pros and Cons of Geothermal Energy