oceanic energy - site.iugaza.edu.pssite.iugaza.edu.ps/wp-content/uploads/04 oceanic energy.pdf ·...

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Oceanic Energy

Assistant Professor Mazen AbualtayefEnvironmental Engineering Department

Islamic University of Gaza, Palestine

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Adapted from a presentation by

Professor S.R. LawrenceLeeds School of Business, Environmental Studies

University of Colorado, Boulder, CO, USA

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Course Outline

Renewable

Hydro Power

Wind Energy

Oceanic Energy

Solar Power

Geothermal

Biomass

Sustainable

Hydrogen & Fuel Cells

Nuclear

Fossil Fuel Innovation

Exotic Technologies

Integration

Distributed Generation

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Oceanic Energy Outline

Overview

Tidal Power

Technologies

Environmental

Impacts

Economics

Future Promise

Wave Energy

Technologies

Environmental

Impacts

Economics

Future Promise

Assessment

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Overview of Oceanic Energy

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Sources of New Energy

Boyle, Renewable Energy, Oxford University Press (2004)

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Global Primary Energy Sources 2002


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Renewable Energy Use – 2001


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Tidal Power

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Tidal Motions


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Tidal Forces


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Natural Tidal Bottlenecks


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Tidal Energy Technologies

1. Tidal Turbine Farms

2. Tidal Barrages (dams)

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1. Tidal Turbine Farms

MCT

Swan turbines

Deep water current turbines

Oscillating turbines

Polo turbines

Land tides

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Tidal Turbines (MCT Seagen)

750 kW – 1.5 MW

15 – 20 m rotors

3 m pile

10 – 20 RPM

Deployed in multi-unit

farms or arrays

Like a wind farm, but

Water 800x denser than air

Smaller rotors

More closely spaced

http://www.marineturbines.com/technical.htm

MCT Seagen Pile

MCT: Marine current turbines

Video

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Tidal Turbines (Swanturbines)

Direct drive to generator

No gearboxes علب التروس

Gravity base (concrete block)

Versus a bored foundation

Fixed pitch turbine blades

Improved reliability

But trades off efficiency

http://www.darvill.clara.net/altenerg/tidal.htm

Video

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Deeper Water Current Turbine


Video

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Oscillating Tidal Turbine

Oscillates up and down

150 kW prototype

operational (2003)

Plans for 3 – 5 MW

prototypes


http://www.engb.com

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Polo Tidal Turbine

Vertical turbine blades

Rotates under a

tethered ring حلقة مربوطة

50 m in diameter

20 m deep

600 tons

Max power 12 MW


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Power from Land Tides (!)

http://www.geocities.com/newideasfromtelewise/tidalpowerplant.htm

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Advantages of Tidal Turbines

Low Visual Impact

Mainly, if not totally submerged.

Low Noise Pollution

Sound levels transmitted are very low

High Predictability

Tides predicted years in advance, unlike wind

High Power Density

Much smaller turbines than wind turbines for the

same power

http://ee4.swan.ac.uk/egormeja/index.htm

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Disadvantages of Tidal Turbines

High maintenance costs

High power distribution costs

Somewhat limited upside capacity

Intermittent power generation

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2. Tidal Barrage Schemes

Barrages

Offshore lagoons

Fences

//upload.wikimedia.org/wikipedia/commons/f/f5/ThomasFulljamesSevernBarrage01.jpg

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Definitions

Barrage

An artificial dam to increase the depth of water for

use in irrigation or navigation, or in this case,

generating electricity.

Flood

The rise of the tide toward land (rising tide)

Ebb

The return of the tide to the sea (falling tide)

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Potential Tidal Barrage Sites


Only about 20 sites in the world have been identified as possible tidal barrage stations

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Schematic of Tidal Barrage


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Cross Section of a Tidal Barrage

http://europa.eu.int/comm/energy_transport/atlas/htmlu/tidal.html

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Tidal Barrage Bulb Turbine


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Tidal Barrage Rim Generator


Canada. An annual output of 50GWh

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Tidal Barrage Tubular Turbine


Sihwa Lake Tidal Power Barrage

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Video Sihawa lake (South

Korea)

This 254 MW

(10x25.4MW), $250

million project is the

first world’s largest

Mean tidal range is

5.6m

The basin area was

reduced to around

30 km2

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La Rance Tidal Power Barrage

Rance River estuary, Brittany (France)

2nd Largest in world (1st in Korea)

Completed in 1966

24×10 MW bulb turbines (240 MW)

5.4 meter diameter

Capacity factor of ~40%

Maximum annual energy: 2.1 TWh

Realized annual energy: 840 GWh

Electric cost: 1.8¢/kWh

Tester et al., Sustainable Energy, MIT Press, 2005Boyle, Renewable Energy, Oxford University Press (2004)

http://en.wikipedia.org/wiki/Rance_Tidal_Power_Station

Video

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La Rance Tidal Power Barrage

http://www.stacey.peak-media.co.uk/Brittany2003/Rance/Rance.htm

The system used

consists of a dam

330m long and a

22km2 basin with a

tidal range of 8.5m,

it incorporates a

lock to allow

passage for small

craft

Construction cost:

€95m (1967) –

about €580m

(2009)

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La Rance River, Saint Malo

http://upload.wikimedia.org/wikipedia/commons/e/eb/Barrage_de_la_Rance.jpg

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La Rance Barrage Schematic


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Cross Section of La Rance Barrage

Tide going out

sea

river

http://en.wikipedia.org/wiki/File:Coupebarrage_Rance.jpg

//upload.wikimedia.org/wikipedia/commons/2/25/Coupebarrage_Rance.jpg

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La Rance Turbine Exhibit

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Tidal Barrage Energy Calculations

ARE

gRARmgRE

21397

2/)(2/

R = range (height) of tide (in m)

A = area of tidal pool (in km2)

m = mass of water

g = 9.81 m/s2 = gravitational constant

= 1025 kg/m3 = density of seawater

0.40 = capacity factor (20-40%)

kWh per tidal cycle

Assuming 706 tidal cycles per year (12 hrs 24 min per cycle)

AREyr

2610997.0

Tester et al., Sustainable Energy, MIT Press, 2005

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La Rance Barrage Example

= 40%

R = 8.5 m

A = 22 km2

633

)22)(5.8)(40.0(10997.0

10997.0

26

26

yr

yr

yr

E

E

ARE

GWh/yr


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Proposed Severn Barrage (1989)

http://en.wikipedia.org/w/index.php?title=File:Severn_Barrages_map.svg&page=1

Video

//upload.wikimedia.org/wikipedia/commons/b/b0/Severn_Barrages_map.svg

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Never constructed, but instructive

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Severn River estuary

Border between Wales and England

216 × 40 MW turbine generators (9.0m dia)

8,640 MW total capacity

17 TWh average energy output

Ebb generation with flow pumping

16 km total barrage length

$15 billion estimated cost (1989)

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Severn Barrage

Layout


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Severn Barrage Proposal

Effect on Tide Levels


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Power Generation over Time


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Capital Costs


~$15 billion

(1988 costs)


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Energy Costs


~10¢/kWh

(1989 costs)

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Capital Costs versus Energy Costs


1p 2¢

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Offshore Tidal Lagoon


Read this article Friends of the Earth Briefing: Tidal Lagoon vs. Barrage

http://tidalelectric.com/news-friends.shtml

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Tidal Fence

Array of vertical axis tidal

turbines

No effect on tide levels

Less environmental impact

than a barrage

1000 MW peak (600 MW

average) fences soon


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Promising Tidal Energy Sites

Country Location TWh/yr GW

Canada Fundy Bay 17 4.3

Cumberland 4 1.1

USA Alaska 6.5 2.3

Passamaquody 2.1 1

Argentina San Jose Gulf 9.5 5

Russia Orkhotsk Sea 125 44

India Camby 15 7.6

Kutch 1.6 0.6

Korea 10

Australia 5.7 1.9

http://europa.eu.int/comm/energy_transport/atlas/htmlu/tidalsites.html

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Tidal Barrage Environmental Factors

Changes in estuary ecosystems

Less variation in tidal range

Fewer mud flats

Less turbidity – clearer water

More light, more life

Accumulation of silt

Concentration of pollution in silt

Visual clutter

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Advantages of Tidal Barrages

High predictability

Tides predicted years in advance, unlike wind

Similar to low-head dams

Known technology

Protection against floods

Benefits for transportation (bridge)

Some environmental benefits

http://ee4.swan.ac.uk/egormeja/index.htm

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Disadvantages of Tidal Turbines

High capital costs

Few attractive tidal power sites worldwide

Intermittent power generation

Silt accumulation behind barrage

Accumulation of pollutants in mud

Changes to estuary ecosystem

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Wave Energy

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Wave Structure


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Wave Frequency and Amplitude


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Wave Patterns over Time


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Wave Power Calculations

2

2

es THP

Hs2 = Significant wave height (m)

Te = average wave period (sec)

P = Power in kW per meter of wave crest length

Example: Hs = 3m, Te = 10sec

m

kWTHP es 45

2

103

2

22

m

kWTHP es 5.3

2

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2

22

Gaza: Hs = 1m, Te = 7sec

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Global Wave Energy Averages

http://www.wavedragon.net/technology/wave-energy.htm

Average wave energy (est.) in kW/m (kW per meter of wave length)

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Wave Energy Potential

Potential of 1,500 – 7,500 TWh/year 10 and 50% of the world’s yearly electricity demand

IEA (International Energy Agency)

200,000 MW installed wave and tidal energy power forecast by 2050 Power production of 6 TWh/y

Load factor of 0.35

DTI and Carbon Trust (UK)

“Independent of the different estimates the potential for a pollution free energy generation is enormous.”


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Wave Energy Technologies

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Wave Concentration Effects


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Tapered Channel (Tapchan)

http://www.eia.doe.gov/kids/energyfacts/sources/renewable/ocean.html

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Oscillating Water Column

http://www.oceansatlas.com/unatlas/uses/EnergyResources/Background/Wave/W2.html

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Oscillating Column Cross-Section


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LIMPET Oscillating Water Column

Completed 2000

Scottish Isles

Two counter-rotating

Wells turbines

Two generators

500 kW max power


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“Mighty Whale” Design – Japan

http://www.jamstec.go.jp/jamstec/MTD/Whale/

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Might Whale Design


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Turbines for Wave Energy

Boyle, Renewable Energy, Oxford University Press (2004) http://www.jamstec.go.jp/jamstec/MTD/Whale/

Turbine used in Mighty Whale

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Ocean Wave Conversion System

http://www.sara.com/energy/WEC.html

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Wave Conversion System in Action

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Wave Dragon


Wave DragonCopenhagen, Denmark

http://www.WaveDragon.net

Click Picture for Video

WaveDragon_overtopping_and_turbines.mpeg

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Wave Dragon Energy Output

in a 24kW/m wave climate = 12 GWh/year




in a 72kW/m wave climate = 52 GWh/year.


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Declining Wave Energy Costs


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Wave Energy Power Distribution


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Wave Energy Supply vs. Electric Demand


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Wave Energy

Environmental Impacts

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Wave Energy Environmental Impact

Little chemical pollution

Little visual impact

Some hazard to shipping

No problem for migrating fish, marine life

Extract small fraction of overall wave energy

Little impact on coastlines

Release little CO2, SO2, and NOx

11g, 0.03g, and 0.05g / kWh respectively


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Wave Energy

Summary

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Wave Power Advantages

Onshore wave energy systems can be incorporated

into harbor walls and coastal protection

Reduce/share system costs

Providing dual use

Create calm sea space behind wave energy

systems

Development of mariculture

Other commercial and recreational uses;

Long-term operational life time of plant

Non-polluting and inexhaustible supply of energy


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Wave Power Disadvantages

High capital costs for initial construction

High maintenance costs

Wave energy is an intermittent resource

Requires favorable wave climate.

Investment of power transmission cables to shore

Degradation of scenic ocean front views

Interference with other uses of coastal and offshore areas navigation, fishing, and recreation if not properly sited

Reduced wave heights may affect beach processes in the littoral zone


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Wave Energy Summary

Potential as significant power supply (1 TW)

Intermittence problems mitigated by

integration with general energy supply

system

Many different alternative designs

Complimentary to other renewable and

conventional energy technologies


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Future Promise

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World Oceanic Energy Potentials (GW)

Source

Tides

Waves

Currents

OTEC1

Salinity

World electric2

World hydro

Potential (est)

2,500 GW

2,7003

5,000

200,000

1,000,000

4,000

Practical (est)

20 GW

500

50

40

NPA4

2,800

550

1 Temperature gradients2 As of 1998

3 Along coastlines 4 Not presently available


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Specific carbon dioxide emissions of

various fuels

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Solar Power – Next Week

http://www.c-a-b.org.uk/projects/tech1.jpg

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