Index

• Definition

• Methods:

-Tidal barrage (diagram, operation, advantages and disadvantages) -TSG (diagram, operation, advantages and disadvantages) -DTP (diagram, operation, advantages and disadvantages) -Tidal lagoon (diagram, operation, advantages and disadvantages)

• Production in Europe

• Use (worldwide, Europe and Spain)

• Conclusions

• Credits

Definition of tidal power

It's the energy that makes use of tides to generate electricity.

These power plants are in an experimental stage and their level of production is still very low.

Methods of generating tidal energy

• Tidal barrage

• Tidal stream generator (TSG)

• Dynamic tidal power (DTP)

• Tidal lagoon

Diagram of a tidal barrage

How does a tidal barrage operate?

A tidal barrage uses the potential energy produced by the difference in height between high tides and low tides.

Advantages and disadvantages of tidal barrages

Advantages:- They don't produce any waste or greenhouse gases.- Tides are predictable.- The energy that they produce is renewable.

Disadvantages:- The high cost of the infrastructure.- Global shortage of viable sites.- Environmental issues.- Tidal barrages only produce energy for about 10 hours a day.

Diagram of a tidal stream generator

How does a tidal stream generator operate?

Tidal stream generators make use of the kinetic energy of the water which comes up and down with the tide by moving the turbines.

Advantages and disadvantages of tidal stream generators

Advantages:- They are low-cost compared with tidal barrages.- They have a smaller ecological impact than tidal barrages.- They don't produce any waste or greenhouse gases.- Tides are predictable.- The energy that they produce is renewable.

Disadvantages:- Grid connection.- The pipes can be dangerous for animals and humans.

Dynamic tidal power

DTP advantages:- No areas are enclosed.- It doesn't produce any waste or greenhouse gases.- Tides are predictable.- It’s a renewable source of energy.

DTP disadvantages:- It’s very expensive.- Global shortage of viable sites.

DTP is an untried but promising technology that would exploit an interaction between potential and kinetic energies in tidal flows.

It means that very long dams (30–50 km long) would be built from the coast straight out into the sea or ocean.

Tidal lagoon

Advantages: - It doesn't produce any waste or greenhouse gases.- Tides are predictable.- Renewable resource.

Disadvantages:- It’s more expensive than tidal barrages.

A newer tidal energy design option is to construct circular retaining walls embedded with turbines that can capture the potential energy of tides.

The reservoirs created are similar to those of tidal barrages.

Production in Europe

The production of tidal energy in Europe is so low that it isn’t usually represented in graphics or it appears under the category of “others”.

Use of tidal energy in Spain

In Spain it's used on a trial basis in Mutriku (Gipuzkoa) and on the shores of Santoña (Cantabria).

Use of tidal energy in Europe

The biggest tidal energy power station in Europe is located on the mouth of River Ranch in France. It has been operational since 1967, with a power of 240MW, covering the energetic needs of 10,000 homes in the French region of Britanny.

This energy is frequently used in the UK too.

Use of tidal energy worldwide

The biggest tidal energy plant in the world is in south Korea, the new Sihwa Lake Tidal Power Station, with 254MW.

Tidal energy is used in other countries like Japan, China, Australia, Canada or New Zealand.

ConclusionsAlthough tidal energy is a clean, predictable and renewable energy, it has three drawbacks: very expensive infrastructures, limited availability of sites with the specific requirements and an insufficiently developed technology.

Its efficiency is also lower than other energies (wind, hydraulic, solar, etc.).

In the next few years, new advances, research and the construction of cheaper infrastructures will make tidal energy more usual because of its predictability.

Credits

Done by:

Sabela Martínez Tomé Laura Pérez López Pablo Manuel Piñeiro Insua

Bilingual section of Technology Group 3º ESO-B IES Praia Barraña – Boiro (Spain) March, 2016