Tidal Power Reading Answers: IELTS Reading Practice Test

This passage examines tidal energy as a renewable power source, covering two main technologies: tidal barrages, which use the rise and fall of sea levels, and tidal stream generators, which work like underwater wind turbines. It discusses the La Rance barrage in France, environmental concerns about barrages, and the mechanical design of tidal stream devices. The passage is from Cambridge IELTS 9, Academic Test 1, Reading Passage 1.

You should spend about 20 minutes on Questions 1–13, which are based on the passage below.

This passage contains two question types: True/False/Not Given (Questions 1–7) and Diagram Labelling (Questions 8–13).

Paragraph A 

Tidal power is a form of hydropower that converts energy from the tides into useful forms, particularly electricity. Tides are more predictable than wind energy and solar power. Among sources of renewable energy, tidal power has traditionally suffered from relatively high cost and limited availability of sites with sufficiently high tidal ranges or flow velocities, thus having so far been used to generate relatively small amounts of electricity. However, many recent technological developments and improvements, both in design (e.g. dynamic tidal power, tidal lagoons) and turbine technology (e.g. new axial turbines, cross flow turbines), indicate that the total availability of tidal power may be much higher than previously assumed, and that economic and environmental costs may be brought down to competitive levels. Historically, tide mills have been used, both in Europe and on the Atlantic coast of North America.

Paragraph B 

The world's first commercial-scale and grid-connected tidal stream generator, SeaGen, was installed in Strangford Lough in Northern Ireland. The tidal stream generator concept was pioneered by Peter Fraenkel, the engineering director of Marine Current Turbines. Tidal stream generators draw energy from water currents in much the same way as wind turbines draw energy from air currents. The stronger the tidal flow, the more energy can be generated. The most powerful tidal current in the world occurs in the Pentland Firth between mainland Scotland and Orkney, which can reach speeds of 4–5 m/s.

Paragraph C 

Tidal barrages make use of the potential energy in the difference in height between high and low tides. Barrages are essentially dams across the full width of a tidal estuary, and suffer from very high civil infrastructure costs, a worldwide shortage of viable sites and environmental issues. The La Rance tidal power plant in Brittany, France, is the world's largest tidal power station by installed capacity. It has been operating since 1966 and is run by Électricité de France. The installed capacity is 240 MW, with an average annual output of approximately 540 GWh.

Paragraph D 

Tidal barrages can cause environmental issues. When a barrage is built across an estuary, the high tidal range that makes the location attractive for power generation may be significantly reduced. The change in tidal range affects the ecosystem of the estuary, potentially causing irreversible environmental damage. Building a barrage can also result in a loss of habitat for shorebirds and other animals that depend on the intertidal zone. Fish migration is also affected, as barrages can block fish from reaching their spawning grounds.

Paragraph E 

Tidal stream generators have far less environmental impact than barrages. They do not require the construction of a dam or barrage. They can be placed on the seabed, where tidal streams are strongest. Because they are submerged, they have little visual impact and can coexist with commercial shipping lanes. The technology is still under development, and costs remain relatively high. But the environmental advantages over barrages are significant and well recognised by planners and governments.

Paragraph F 

A tidal stream turbine looks similar to a wind turbine. The main components include: the blade, which rotates as water flows past; the nacelle, which contains the gearbox and generator and is mounted at the top of the tower; the tower or monopole, which supports the nacelle and blades above the seabed; a cable, which runs from the nacelle to the seabed and carries the generated electricity to shore; the seabed anchor system, which holds the structure in place; and the generator itself, housed inside the nacelle, which converts rotational energy into electricity.

Paragraph G 

The future of tidal power looks promising. Costs are falling as the technology matures, and several large-scale tidal projects are now under development around the world. Countries with strong tidal resources, such as the United Kingdom, Canada, and South Korea, are investing heavily in tidal stream technology. As with wind and solar power, the economics of tidal energy are expected to improve substantially as more installations come online and the technology is refined.

True/False/Not Given: Questions 1–7

Do the following statements agree with the information given in the reading passage?

In boxes 1–7 on your answer sheet, write: TRUE if the statement agrees with the information FALSE if the statement contradicts the information NOT GIVEN if there is no information on this

1. 1. Tidal power is considered more predictable than wind or solar energy.
2. 2. SeaGen, the world's first commercial tidal stream generator, was built in Scotland.
3. 3. The Pentland Firth tidal current is used to power homes in Orkney.
4. 4. The La Rance tidal barrage has been operating for several decades.
5. 5. Tidal barrages have no impact on fish populations in the affected estuaries.
6. 6. Tidal stream generators have less visual impact than tidal barrages.
7. 7. The United Kingdom currently produces more tidal energy than any other country.

Diagram Labelling: Questions 8–13

Label the diagram of a tidal stream turbine below.

Choose NO MORE THAN ONE WORD from the passage for each answer.

Write your answers in boxes 8–13 on your answer sheet.

1.   8. The part that rotates as water flows past: ________
2.   9. The housing that contains the gearbox and generator: ________
3. 10. The structure that supports the turbine above the seabed: ________
4. 11. The component that carries electricity to shore: ________
5. 12. The surface on which the anchor system rests: ________
6. 13. The component inside the nacelle that converts rotational energy: ________