Tidal energy: advantages and disadvantages

While energy is required for the evolution of life forms on earth, a significant part of what we use today is obtained from non-renewable sources. This implies that once they are exhausted, they cannot be replenished. The most important source of non-renewable energy used is fossil fuels, which have taken millions of years to form. This requires that we look for alternative sources already existing in nature, which cannot be created or destroyed but can be transferred from one form to another. The energy of nature: the sun, the wind, the waves, the tides, etc. can be converted into a usable form. One of these renewable energy sources is tidal power . Read on to discover all the advantages and disadvantages existing.

Advantages Tidal EnergyDisadvantages Tidal Energy
  • It is a renewable energy
  • It has zero carbon emission
  • It’s a predictable energy
  • Produces large amounts of electricity
  • There are limited installation locations
  • It is an expensive energy
  • Has negative environmental effects
  • They do not have a constant energy production

What are the tides

The gravitational forces of the sun and moon combined with the rotation of the earth result in an alternating rise and fall of the sea level. In a particular place, it usually occurs twice in a lunar day. The rise in sea level is called high tide , while the fall is called low tide. When the gravitational field of the Earth and the Moon are in a straight line, the influences of these two fields become very strong and cause millions of gallons of water to flow towards the coast resulting in the high tide condition. Similarly, when the gravitational fields of the moon and the earth are perpendicular to each other, the influences of these fields are weakened, causing the water to flow away from the coast and causing a low-tide condition.

When the moon is perfectly aligned with the earth and the sun, the gravitational pull of the sun and the moon on the earth becomes much stronger and the high tides are much higher and the low tides much lower during each tidal cycle. This condition occurs during the full or new moon phase. These tides are known as spring tides . Similarly, another tidal situation arises when the gravitational pull of the moon and the sun face each other canceling their effects. This results in a smaller difference between low tide and high tide due to the less pulling action of the seawater, resulting in weak tides. These weak tides are known as neap tides (they occur during the quarter moon phase).

What is tidal energy

Tidal energy is a renewable energy source that converts, redundancy beats, the energy created from changing tides and currents into usable electricity. Tidal energy can be captured through the use of different types of technologies, such as tidal barriers, tidal current generators, and tidal fences.

All of these types of tidal power plants use tidal turbines , so it is more important to understand how a turbine can capture the kinetic energy within the tides for energy production.

Tidal turbines harness tidal energy in a similar way to how wind turbines capture the winds. As currents and tides change, moving water pushes the turbine blades. It turns a generator that then produces electricity.

Advantages of tidal energy

1. It is renewable

Tidal energy is a renewable energy source, which means that energy is not depleted as it is used . Therefore, as you harness the energy of the changing tides, you do not decrease the amount of energy that the tides can produce in the future. The gravitational pull of the sun and the moon , which controls the tides, will not soon cease to exist.

2. It has zero carbon emissions

In addition to being a renewable energy source, tidal power plants do not emit greenhouse gases during electricity generation.

Because greenhouse gas emissions are one of the main causes of climate change, finding zero-emission energy sources is more important than ever.

3. It is predictable

Tidal currents are highly predictable. High and low tides follow well-known cycles , making it easy to know when power will be produced throughout the day. It also makes it easy to know how much energy the turbines will produce, since the power of the tides and currents can be accurately forecast.

4. Produces large amounts of electricity

Tidal power plants can produce large amounts of electricity. One of the main reasons for this is that water is very dense, almost 800 times denser than air . This means that a tidal turbine will produce substantially more power than a wind turbine of the same size.

In addition, even when the water moves at low speed, its density allows it to power a turbine. So tidal turbines have the potential to produce large amounts of electricity even if the water conditions are not ideal.

Disadvantages of tidal energy

1. Limited installation locations

For a tidal power plant to be built, the potential installation site must meet very specific requirements. First, they must be located on a coastline , limiting potential station sites to coastal states.

There are additional requirements that a potential site must meet. For example, tidal power plants must be built in places where the height difference between high tide and low tide is significant enough to power turbines. This limits where power plants can be installed, making it difficult for the widespread deployment of tidal power.

2. It is expensive

One of the biggest drawbacks of tidal power is the high upfront costs . Tidal power turbines must be much stronger than wind turbines, due to the high density of water. The cost of building a tidal power generation plant varies depending on the type of technology they use.

Most of the tidal power plants that are currently in operation are made of tidal dams, which are essentially low-wall dams. The construction of a tidal barrier is extremely expensive, since it is necessary to install a complete concrete structure, plus turbines.

The cost barrier is one of the main reasons that tidal energy has been slow to be adopted.

3. Has environmental effects

Just because tidal energy is renewable doesn’t mean it’s completely environmentally friendly. The construction of tidal power plants can have a substantial impact on the surrounding ecosystem .

Tidal turbines have the same problem that wind turbines face with birds: collisions of marine life. As the turbines rotate, fish and other marine life can swim towards the blades, causing serious injury or death. Tidal turbines also create low-level noise below the water’s surface that negatively impacts marine mammals, such as seals.

Tidal bombardments have an even greater impact on the local environment. Not only do they cause the same problems as turbines alone, but they also have a similar impact to dams. Tidal bombardments prevent fish migration and cause flooding in surrounding areas that forever change the landscape.

4. Energy demand

While tidal energy has predictable energy generation, it does not have constant energy output . We can know exactly when the tidal power plant will generate electricity, but the electricity generation may not match the energy demand.

For example, if the high tide is at noon, the tidal electricity will occur around noon. Peak power demand is typically morning and evening, with the lowest power demand in the middle of the day.

So the tidal power plant will produce all this electricity, but it will not be needed. Therefore, tidal energy should be realistically combined with battery storage to make the most of the energy it produces.

The future of tidal energy

Tidal energy has enormous potential , especially as new technologies continue to develop, such as dynamic tidal energy.

Currently, there are less than ten tidal power plants in operation worldwide. The two most popular tidal power plants, the Rance Tidal Power Station and the Sihwa Lake Tidal Power Station, produce enough power to power 94,507 homes in the United States for an entire year. Not only is it a substantial amount of energy , but it is also predictable and contains no carbon .

However, tidal power plants can have a substantial impact on the surrounding ecosystem, high upfront costs, and there are few suitable sites for them. Hopefully, as technology continues to improve, we will be able to harness the energy stored within the tides.

In the meantime, if you want to start moving away from fossil fuels now, you should consider making the switch to solar power . A solar panel system will not only reduce carbon production, but it will also be able to eliminate your electricity bill altogether.

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