8 Emerging Technologies PPQ

Question 1

Evaluate the constraints in the development of wave and tidal power in the UK and Ireland. {8}

Answer 1

• Significant amount of research and development to make systems which are consistently commercially viable.
• The UK / Ireland operate busy shipping lanes and therefore locating the devices is difficult – need to ensure that they do not impact on navigation.
• Devices need to be robust and able to survive significant changes in sea conditions: they are also required to withstand sea water corrosion.
• Tidal systems require a sufficient difference in high and low tides to ensure efficiency of the technology – not all locations are suitable.

Question 2

Identify two main constraints on developing wave and tidal technologies in Northern Ireland. {2}

Answer 2

• Limited availability of suitable sites.
• Environmental support.
• Government support.
• Cost of development.

Question 3

Tidal stream generators and tidal barrages are the two main generating methods for tidal power. Compare and contrast these two methods.
{5}

Answer 3

Tidal stream generators make use of the kinetic energy of moving water to power turbines {1}
Tidal barrages make use of the potential energy in the difference in water height between high and low tides {1}.
With the receding tide, this potential energy is then converted into kinetic energy as the water is released through large turbines that create electrical power through the use of generators {1}
Tidal stream generators have the advantage of being much cheaper to build {1} And do not have as much of an environmental impact as tidal barrage {1}.

Question 4

two advantages that tidal stream generation has over a tidal barrage installation.

Answer 4

• They are cheaper to construct.
• They are smaller and have less environmental impact.
• The turbine blades turn slowly and have less effect on sea life.

Question 5

outline the operational processes of an attenuator type device. (5)

Answer 5

These devices are orientated parallel to the direction of the wave. {1}

Attenuators are typically a series of long cylindrical floating devices connected to each other with hinges and anchored to the seabed (Pelamis).

The cylindrical parts drive hydraulic rams in the connecting sections {1} and those in turn drive an electrical generator {1}.

The devices send the electricity through cables to the sea floor where it then travels through a cable to shore {1}.

Question 6

Explain how a tidal barrage generate energy form the tides. {5}

Answer 6

• A barrage is built across an estuary with gates and turbines built into the wall of the dam {1}.
• As the tide flow in the gates are open and the turbines are operated producing electricity {1}.
• At high tide the gates are closed trapping the water inside {1}.
• When water outside has fallen sufficiently (e.g. 5m) the gates are opened
{1}.
• The released water turns the turbines again producing electricity {1}.

Question 7

Describe three environmental implications that must be considered when deciding to install wave energy convertors at a particular site. (3)

Answer 7

• Impact on marine life and habitat.
• Risk of toxic pollution.
• Visual and noise impact.
• Conflict with other sea users.