Tidal Energy Pros and Cons

The worldwide potential for tidal power is estimated to be 700 TWh a year. Currently, tidal power is early in the development stages and not able to compete with fossil fuels. However, Focus on renewable energy sources and demand for clean energy contributes to a rapid development of methods to harness this energy source. What are the pros and cons of tidal energy and what can we expect in the future?

This article will only consist of the most important advantages and disadvantages of tidal energy in general. If you aren’t familiar with these technologies yet you should read the following article first: How Does Tidal Power Work?


Advantages of Tidal Energy

1. Renewable

Tidal Energy is a renewable energy source. This energy source is a result of the gravitational fields from both the sun and the moon, combined with the earth’s rotation around its axis, resulting in high and low tides.

It is this difference in potential energy that is the source of power generation from tidal energy, whether we are talking about stream generators, tidal barrages or more the more recent technology, dynamic tidal power (DTP).

So, why is tidal energy renewable? Compared to fossil fuels or nuclear reserves, the gravitational fields from the sun and the moon, as well as the earth’s rotation around its axis won’t cease to exist any time soon.


2. Green

Tidal power is an environmentally friendly energy source. In addition to being a renewable energy, it does not emit any climate gases and does not take up a lot of space.

However, there are currently very few examples from real tidal power plants and their effects on the enviroment. An important task is therefore to study and assess these things.


3. Predictable

Tidal currents are highly predictable. High and low tide develop with well-known cycles, making it easier to construct the system with right dimensions, since we already know what kind of powers the equipment will be exposed to.

Because of this, even though the turbines that are being used (tidal stream generators that is) are very similar to wind turbines, both the physical size and the installed capacity has entirely other limitations.


4. Effective at Low Speeds

Water has 1000 times higher density than air, which makes it possible to generate electricity at low speeds. Calculations show that power can be generated even at 1m/s (equivalent to a little over 3ft/s).


5. Long Lifespans

We have no reason to believe that tidal power plants are not long lived. This ultimately reduces the cost these power plants can sell their electricity, making tidal energy more cost-competitive. The tidal barrage power plant La Rance was opened already in 1966 and still generates large amounts of electricity.

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Disadvantages of Tidal Energy

1. Environmental Effects

As previously mentioned, the effects tidal power plants have on the environment are not completely determined yet. We know that these power plants generate green electricity

Tidal barrages relies on manipulation on ocean levels and therefore potentially have the environmental effects on the environment similar to those of hydroelectric dams. Technological solutions that will resolve some of these issues are currently being developed.


2. Close to Land

Tidal power plants needs to be constructed close to land. This is also an area where technological solutions are being worked on. Hopefully in a few years we can exploit weaker tidal currents, at locations further out in the sea.


3. Expensive

It is important to realize that the methods for generating electricity from tidal energy is a relatively are relatively new technologies. It is projected that tidal power will be commercially profitable within 2020 with better technology and larger scales.

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Last Update: 16 October 2012


  1. Linea Payne says

    What is the impact on the crustaceans and other life in the tidal pools and yide areas of the oceans and thr rivers as well? don’t the little critters get sucked up into the turbines and become ‘fish stew’? that would be a huge impact on oceanic or other water life. so not so green then.(?)

  2. NO NAME says

    I found a mistake. Where it says “expensive”, shouldn’t it say “It is important to realize that the methods for generating electricity from tidal energy is relatively new technology.”?
    If I’m wrong, please correct me.

  3. emmi wilson says

    YESSSS!! thank you so much! i had to do a research on the pros and cons of different types of energy sources and i used this website and it really helped. thanks again.

  4. john roseborough says

    tidal energy, the rise and fall of sea water levels is the most efficient. no cons no environmental impact. coastal cities should be harnessing this limitless supply of power instead of burning coal or using diesel generators. hydro electric dams are expensive and
    not very environmentally friendly.

  5. Sheila says

    Of course, all the alternatives have pros and cons. But there is no alternative to conservation. None of these will be viable if we ignore the fact that the planet is our home – to be nurtured, not exploited.

  6. Dany says

    Actually the turbines move very slowly they don’t move as fast like when you blow air on those little decorational things you put out in your lawn or something. The turbines are much heavier making them move very slowly so very little to no damage is done to the marine life.

  7. jan says

    When we make use of tidal power, we get that energy from somewhere else. The concept of “generating energy” is actually “converting energy”. The tides are the result of the rotation of the earth on its axis and the gravitational attraction between the sun, earth and moon. Tidal energy will slightly decrease this rotation (kinetic energy) because we convert the kinetic energy into another form of energy, such as electricity. The question is how serious this disruption over time will be when this form of power generation is applied globally on a very large scale.

  8. C. Laurence says

    The turbines are designed so that they don’t spin fast enough to do that. The blades do not spin at high speeds in order to prevent aquatic life from being harmed.

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