In addition to the established energy sources such as gas, coal, oil and nuclear, there are a number of other sources that we ought to consider. Two of these are hydro-electric and tidal power. These two sources are similar in that they are both renewable. However, hydro-electric power is more widely used than tidal.

In fact, a substantial amount of electricity is already produced in HEP stations world-wide, whereas tidal stations are still in the very early stages of development. As far as geographical location is concerned, HEP schemes are to be found on lakes and rivers, while tidal schemes are constructed only in estuaries where tidal variation is great.

Tidal ENERGY and US
Tidal Energy


Unfortunately, these are few in number. At present HEP stations are found mainly in Norway, Canada, Sweden and Brazil, whereas tidal plants are in operation in France, the CIS and China. As regards capital outlay, both require very high investment. On the other hand, generating costs are quite low in both cases.

In fact, a large-scale HEP plant is capable of producing power more cheaply than conventional sources, such as coal, oil and nuclear plants. Tidal power also compares favourably with nuclear and oil generated electricity, in terms of production costs. Like HEP stations, tidal barrages have a long life-expectancy. It is estimated that they can operate for over 100 years.

Diagram of Tidal STREAM


With respect to continuity of supply, tidal stations differ from HEP schemes in that they often can only supply power intermittently. HEP stations, however, provide a constant supply of electricity. Turning now to environmental impact, tidal plants do not seem to create too many problems.

In contrast, HEP stations often involve the flooding of large amounts of agricultural land, the destruction of ecological habitats, and may even cause a change in the climate of the area. Both tidal power and HEP have one big disadvantage in that if the demand for power exists at any distance from the generating plant, transmitting the electricity is expensive.


Mark the best choice.
1. Hydro-electric power stations are used more widely than tidal-power stations because they .

a) cost less                b) are geographically less limited

c) are renewable       d) are still in the early stages of development

2. Which of the following statements is true?

a) HEP stations can produce cheaper power than conventional plants but tidal power plants cannot.

b) The capital and generating costs of hydro-electric and tidal power plants are both low.

c) HEP stations are not likely to operate for over a hundred years.

d) Tidal stations are not capable of supplying a continuous flow of electricitiy.


3. With the construction of tidal plants, .

a) the climate of the area does not necessarily change

b) the ecological habitats are often destroyed

c) transmission costs of electricity are reduced

d) flooding of agricultural lands cannot be prevented

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