Severn Tidal Power – a proposal

A Barrage of Issues

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

P 172 Pearson

• Read and make notes (include info from this powerpoint too)

Why is there interest in Tidal Energy?

The UK is committed to reducing its CO2 emission by….

- 60% by 2050It also aims to generate more of its energy

by renewables as follows…- 20% by renewables by 2020

Why the rush?

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 gathering pace with .

What about other types of energythat don’t produce Carbon Emissions?

• Nuclear power?

Wind Energy?

Solar energy?

Tidal Energy?

There are two ways of using tidal energy

1. Tidal Stream – using the current flow

2. Tidal Range – Using rise and fall of tides

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- Doesn’t cause build up of sediment

behind a barrier

Costs- The Severn Estuary is one of many

places where Tidal Stream Energy

has potential

- Relatively low energy output

Tidal Range – Benefits and Costs

Costs- There are multiple costs (many more problems than for Tidal Stream technology), but…

Benefits- The benefits are enormous….

- The Severn Estuary has the second largest tidal range in the world (13 metres)

- A tidal range barrage would have the potential to create 5% of the UK’s energy

- This contributes massively to the government’s target to reduce CO2 emissions

Options for the Tidal Barrage1. Tidal LagoonsBenefits- 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

• Option 2 – Cardiff-Weston Barrage (16km)

Benefits

- This is the most energy efficient and likely option

What are the costs of the 16 Weston-Cardiff Barrage?

1. Building and Construction

Energy from a tidal barrage is not azero carbon option…

- Production of Concrete- Transport

But… these Carbon costs are offsetagainst +120yrs of essentially zero carbon costs during operation

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 unique ecosystem will be altered

3. Increased river levels and flood risk up stream

The Barrage would increase the water levels landwards…

Current level

Predicted level

Part 2 – Role Play

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

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

Mark schemeTo 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?