Tidal Energy

Advantages Vs. Disadvantages

Meng Wanga, Vítor Raposo Silvino Rêgo

a

a Mechanical Engineering Department, Faculty of Engineering,

University of Manitoba, Winnipeg, Canada

Abstract

In this paper, we collected a lot of numerical datas and discussed the advantages and disadvantages

of tidal energy to find out whether tidal energy is a better choice nowadays comparing with other energy

sources. As the advantages we can see that tidal power has an efficiency of approximately 80%, this is

much better efficiency to other renewable energy sources such as solar and wind. But on the other hand

this kind of technology is still very expensive, and if comparing the initial cost to build a “Tidal Energy

Plant” Vs. “Natural Gas Plant”, it is 60% more expensive than the natural gas. In the end of this paper,

after have analyzed all these points we concluded that tidal power is not worth at present.

Keywords: tidal energy; advantages; disadvantages; green energy

1. Introduction Due to global warming becoming increasingly serious, reducing greenhouse gas emission has

become a necessity. As a result, it becomes an international movement to find a new energy source to

replace traditional energy source and reduce the emission of greenhouse gas.

There are many green energy sources in the nature, such as solar, wind, tidal and so on. However,

most of the green energy sources are unpredictable and variable because they are mainly dependent on the

weather. Comparing with other green energy source, tidal energy has significant advantages. First of all,

tidal energy is predictable since tides come and leave cyclically and the period is approximate 12 hours.

Besides, tidal energy is a reliable energy since weather has little effect on tidal energy. However, tidal

energy also has obvious disadvantages. For example, the initial cost for tidal energy is much higher than

other green energy sources. Besides, it also has unpredictable environmental risks. Therefore, it’s very

important to figure out if developing tidal energy is a good choice.

2. Advantages Renewable. The gravitational attraction between the earth and moon, and between the earth and sun

produces tidal energy [7]. Therefore, tidal energy dose not consume any fuels. As long as the moon and

the sun still exist, there will be tidal energy.

Availability. Fast flowing water and large tidal range is the source of tidal energy, this kinetic energy can

turn tidal stream turbine to generate the electricity. The global potential tidal energy exceeds over 120GW

and UK has over 10 GW tidal energy. For Canada, the potential tidal energy exceeds 42 GW [5]. The

Canadian tidal power occupies over 30% of the world’s total tidal energy. Therefore, Canada is very rich

in tidal energy. Bay of Fundy have the highest mean range 11.7 m and can provide 11.7 TWh which is a

very suitable place for building tidal barrage[6].

Figure 1. High potential areas for tidal resources[9]

Reduce pollution. Tidal power does not consume any fuels. There are no greenhouse gases or other

waste formed since there is no chemical reaction. The tidal energy in the world can power 15 million

homes, and saves 70 million tons of carbon [8].

High efficiency. Tidal power is one of the most efficiency energy sources and have an efficiency of 80%

[1]. This efficiency is much higher than other green energy source compared with solar energy and wind

energy.

Reliability. Tidal energy is more predictable than other green energy because tidal energy is mostly

caused by the gravitation between the moon and the earth and gravitation between the sun and the earth.

There are tides coming and leaving twice daily. So the dam can operate every day to generate electricity.

However, other green energy source such as solar power and wind power are dependent on the weather.

Therefore, tidal energy is a more reliable energy.

3. Disadvantages Despite of all the positives points mentioned above about tidal energy, this system of power

generation also has many disadvantages. We can cite as the main disadvantages of this system the high

initial cost of installation when compared to other power generation systems, the various damage to the

marine life, and the fact that there are only few regions in the world where this system of power

generation can be built.

High costs. Tidal power plants are connected with high upfront costs needed for construction, and

therefore cost-competitiveness on global energy market [1]. Looking at a natural gas power generation

plant, the initial cost is about USD 1.1 million per 1 MW, while the initial cost of a tidal plant energy is

around USD 1.8 million per 1 MW, which give to us an initial cost of 60% more than the natural gas

facility. What makes tidal energy expensive is the fact that more technological advancements are required

to make it commercially viable and another point that increases its price is that usually the places where it

is produced are far away from the places where it is consumed what makes the transmission of this energy

expensive and difficult [2].

Damage to marine life. Besides the fact of the high initial cost, the tidal energy system could cause a lot

of damage to marine life. Taking into consideration the barrage systems, it has the disadvantages of

disrupting fish migration and killing fish passing through the turbines although this count with the best

designs, the fish mortality rate per pass through the dam is about 20 to 80% [3]. Another point to be

considered is that gears and hydraulic systems will generate some noise and many marine creatures have

sensitive hearing, and they use sound for navigation, communication and sonar [4]

Few potential places. All the facts above are very important, but the most important factor in relation to

tidal energy is that it is only available in a small number of regions because it requires a basin or gulf that

has a mean tidal range of 7 meters or above. Also it needs semi-diurnal tides where there are two high and

low tides every day, and due to this fact, the tidal system can only generates energy during several hours

per day [5]. If we look around the entire world, there are only about 20 potential places to generate tidal

energy in the efficient way. And if we start to look the potential energy that could be generated in Canada,

there is only one good place where it can be applied, that is the province of British Columbia. But we

should remember that Canada is the second largest country in the world, what makes difficult to transport

the energy from the cost to the central part of the country making this system almost impractical [3].

4. Conclusion What we can conclude about the tidal energy is that despite the fact that it is renewable source of

energy with an efficiency of 80%, and it also helps to reduce greenhouse gas emission, the cost to build a

tidal energy plant is very high, and therefore it is not worth to be built. But on the other hand, this kind of

technology has been developed in a very successful way, and may be in a close future the costs of this

energy system will be much smaller, and therefore it will be worth to use the tidal energy.

Reference

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