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Oceanic Energy

Professor S.R. LawrenceLeeds School of Business

University of Colorado

Boulder, CO 80305

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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

Boyle, Renewable Energy, Oxford University Press (2004)

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Renewable Energy Use – 2001

Boyle, Renewable Energy, Oxford University Press (2004)

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Tidal Power

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Tidal Motions

Boyle, Renewable Energy, Oxford University Press (2004)

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Tidal Forces

Boyle, Renewable Energy, Oxford University Press (2004)

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Natural Tidal Bottlenecks

Boyle, Renewable Energy, Oxford University Press (2004)

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Tidal Energy Technologies

1. Tidal Turbine Farms

2. Tidal Barrages (dams)

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1. Tidal Turbine Farms

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Tidal Turbines (MCT Seagen)

750 kW – 1.5 MW 15 – 20 m rotors 3 m monopile 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

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Tidal Turbines (Swanturbines)

Direct drive to generator No gearboxes

Gravity base Versus a bored foundation

Fixed pitch turbine blades Improved reliability But trades off efficiency

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

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Deeper Water Current Turbine

Boyle, Renewable Energy, Oxford University Press (2004)

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Oscillating Tidal Turbine

Oscillates up and down 150 kW prototype

operational (2003) Plans for 3 – 5 MW

prototypes

Boyle, Renewable Energy, Oxford University Press (2004)

http://www.engb.com

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Polo Tidal Turbine

Vertical turbine blades Rotates under a

tethered ring 50 m in diameter 20 m deep 600 tonnes Max power 12 MW

Boyle, Renewable Energy, Oxford University Press (2004)

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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

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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

Boyle, Renewable Energy, Oxford University Press (2004)

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

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Schematic of Tidal Barrage

Boyle, Renewable Energy, Oxford University Press (2004)

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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

Boyle, Renewable Energy, Oxford University Press (2004)

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Tidal Barrage Rim Generator

Boyle, Renewable Energy, Oxford University Press (2004)

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Tidal Barrage Tubular Turbine

Boyle, Renewable Energy, Oxford University Press (2004)

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La Rance Tidal Power Barrage Rance River estuary, Brittany (France) Largest in world 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: 3.7¢/kWh

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

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La Rance Tidal Power Barrage

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

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La Rance River, Saint Malo

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La Rance Barrage Schematic

Boyle, Renewable Energy, Oxford University Press (2004)

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Cross Section of La Rance Barrage

http://www.calpoly.edu/~cm/studpage/nsmallco/clapper.htm

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La Rance Turbine Exhibit

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Tidal Barrage Energy Calculations

ARE

gRARmgRE21397

2/)(2/

R = range (height) of tide (in m)A = area of tidal pool (in km2)m = mass of waterg = 9.81 m/s2 = gravitational constant = 1025 kg/m3 = density of seawater 0.33 = capacity factor (20-35%)

kWh per tidal cycle

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

AREyr2610997.0

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

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La Rance Barrage Example

= 33%R = 8.5 mA = 22 km2

517

)22)(5.8)(33.0(10997.0

10997.026

26

yr

yr

yr

E

E

ARE

GWh/yr

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

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Proposed Severn Barrage (1989)

Boyle, Renewable Energy, Oxford University Press (2004)

Never constructed, but instructive

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Proposed Severn Barrage (1989) 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 (9.6 mi) total barrage length £8.2 ($15) billion estimated cost (1988)

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Severn Barrage

Layout

Boyle, Renewable Energy, Oxford University Press (2004)

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Severn Barrage Proposal

Effect on Tide Levels

Boyle, Renewable Energy, Oxford University Press (2004)

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Severn Barrage Proposal

Power Generation over Time

Boyle, Renewable Energy, Oxford University Press (2004)

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Severn Barrage Proposal

Capital Costs

Boyle, Renewable Energy, Oxford University Press (2004)

~$15 billion(1988 costs)

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

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Severn Barrage Proposal

Energy Costs

Boyle, Renewable Energy, Oxford University Press (2004)

~10¢/kWh(1989 costs)

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Severn Barrage Proposal

Capital Costs versus Energy Costs

Boyle, Renewable Energy, Oxford University Press (2004)

1p 2¢

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Offshore Tidal Lagoon

Boyle, Renewable Energy, Oxford University Press (2004)

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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

Boyle, Renewable Energy, Oxford University Press (2004)

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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

Boyle, Renewable Energy, Oxford University Press (2004)

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Wave Frequency and Amplitude

Boyle, Renewable Energy, Oxford University Press (2004)

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Wave Patterns over Time

Boyle, Renewable Energy, Oxford University Press (2004)

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Wave Power Calculations

2

2es TH

P

Hs2 = Significant wave height – 4x rms water elevation (m)

Te = avg time between upward movements across mean (s) P = Power in kW per meter of wave crest length

Example: Hs2 = 3m and Te = 10s

m

kWTHP es 45

2

103

2

22

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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.”

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

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Wave Energy Technologies

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Wave Concentration Effects

Boyle, Renewable Energy, Oxford University Press (2004)

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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

Boyle, Renewable Energy, Oxford University Press (2004)

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LIMPET Oscillating Water Column

Completed 2000 Scottish Isles Two counter-rotating

Wells turbines Two generators 500 kW max power

Boyle, Renewable Energy, Oxford University Press (2004)

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“Mighty Whale” Design – Japan

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

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Might Whale Design

Boyle, Renewable Energy, Oxford University Press (2004)

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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

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

Wave DragonCopenhagen, Denmarkhttp://www.WaveDragon.net

Click Picture for Video

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Wave Dragon Energy Output

in a 24kW/m wave climate = 12 GWh/year in a 36kW/m wave climate = 20 GWh/year in a 48kW/m wave climate = 35 GWh/year in a 60kW/m wave climate = 43 GWh/year in a 72kW/m wave climate = 52 GWh/year.

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

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Declining Wave Energy Costs

Boyle, Renewable Energy, Oxford University Press (2004)

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Wave Energy Power Distribution

Boyle, Renewable Energy, Oxford University Press (2004)

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Wave Energy Supply vs. Electric Demand

Boyle, Renewable Energy, Oxford University Press (2004)

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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

Boyle, Renewable Energy, Oxford University Press (2004)

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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

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

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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

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

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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

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

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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

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

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Solar Power – Next Week

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