Severn Tidal Power

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Severn Tidal Power

• A Barrage of Issues

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Why is this an important case study?

• Demonstrates Environmental pressures caused by
  crowded coasts
• Demonstrates the conflicting interests of
  different stake holders on a coastal location
• Demonstrates a current decision making challenge
  on the coast

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Why is there interest in Tidal Energy?

• The UK is committed to reducing its CO2
• emission by.
• - 20 by 2010
• - 60 by 2050
• It also aims to generate more of its energy by
  renewables as follows
• - 10 by renewables by 2010
• - 20 by renewables by 2020

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Why the rush?
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(No Transcript)
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Also, are our sources of Oil/ Gas reliable?
Seized tanker anchors off Somalia
Pirates have anchored a hijacked Saudi oil tanker
off the Somali coast, as the spate of hijackings
gathered pace with two more ships seized on
Tuesday.
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What about other types of energythat dont
produce Carbon Emissions?

• Nuclear power???

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• Wind Energy???

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• Solar energy???

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• Tidal Energy???

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There are two ways of using tidal energy

• 1. Tidal Stream using the current flow

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• 2. Tidal Range Using rise and fall of tides

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The planners have had to look at the options of
both Tidal Stream and Tidal Range Technology and
their respective benefits and costs on the Severn
Estuary.

• Tidal Stream Benefits and Costs
• Benefits
• Could be set up in the outer estuary (off Shore)
• Less of a shipping hazard
• Doesnt cause build up of sediment
• Costs
• The Severn Estuary is one of many
• places where Tidal Stream Energy
• has potential
• - Relatively low energy output

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• Tidal Range Benefits and Costs
• Costs
• - There are multiple costs (many more problems
  than for Tidal Stream technology), but
• Benefits
• - The benefits are enormous.

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• - The Severn Estuary has the second largest
  tidal range in the world (24ft)
• - A tidal range barrage would have the potential
  to create 5 of the UKs energy
• - This contributes massively to the governments
  target to reduce CO2 emissions

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Options for the Tidal Barrage

• Tidal Lagoons
• Benefits
• Favoured by Greenpeace
• Allows natural flow of the river
• Prevents damage to ecosystem upstream (in land)
• Costs
• Massive wall needed
• Increased Cost
• Increased CO2 used in building

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• Option 2 Cardiffe-Weston Barrage (16km)

Benefits - This is the most energy efficient and
likely option
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What are the costs of the 16 Weston-Cardiff
Barrage?

• Building and Construction
• Energy from a tidal barrage is not a
• zero carbon option
• Production of Concrete
• Transport
• But These Carbon costs are offset
• against 120yrs of essentially zero
• carbon costs during operation

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• 2. Alteration of Tides/ Currents
• The Severn Estuary has a complex Dynamic
  Equilibrium of
• - Waves, Tides, Currents,
• - Wind and Rain
• - Sediment supply
• Vegetation
• Human Impact
• This is a high stress environment for wildlife.
  If the Severn Barrage allows deposition of silt,
  there will be competition from new species and a
  uniqu ecosystem will be altered

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• 3. Increased river levels and flood risk up stream

The Barrage would increase the water levels
landwards
Predicted level
Current level
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Lesson 2 Role Play Activity

• You will be put into groups and given one of the
  following stakeholder roles. Use the grid sheet
  to select facts and ideas to support your
  arguments.
• The Government (you are concerned about meeting
  CO2 Emission Targets)
• Environmentalists (you are concerned with
  protecting local habitats and endangered species)
• The Trade Union of Dock Workers (You are
  concerned with access on the Severn Estuary
• North Somerset Tourist Board (You are interested
  in promoting tourism on the Severn Estuary)
• South West Employment Bureau (you are interested
  in providing jobs and developing the local
  economy)
• Government Department for Transport (You are
  interested in land access between Wales and
  England)
• The Environment Agency (you are concerned about
  flood risk)

• In your presentation you must
• Say whether you are in favour of the new Barrage
• Use evidence to justify your opinion
• Be balanced e.g. show that you are aware of
  both sides of the argument
• Put forward any recommendations that make the
  barrage more acceptable to you

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Examine the conflicts associated with a proposed
coastal development of your choice (12 marks)
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Mark scheme

• To achieve maximum marks
• Are clear opinions given for those for and
  against the development?
• Are key concepts explained?
• Is evidence used to support arguments?
• Is a valid conclusion drawn as to the suitability
  of the development?
• Is there clear evidence of planning and
  organisation?
• Is there good use of geographical terminology?

• Successes-
• Targets -