Oceanic Energy
Professor S.R. Lawrence
Leeds School of Business
University of Colorado
Boulder, CO 80305
1
Course Outline

Renewable

Sustainable


Hydro Power
Wind Energy

Oceanic Energy


Solar Power
Geothermal
Biomass






Hydrogen & Fuel Cells
Nuclear
Fossil Fuel Innovation
Exotic Technologies
Integration

Distributed Generation
2
Oceanic Energy Outline


Overview
Tidal Power




Technologies
Environmental
Impacts
Economics
Future Promise

Wave Energy
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
Technologies
Environmental
Impacts
Economics
Future Promise
Assessment
3
Overview of Oceanic Energy
4
Sources of New Energy
5
Boyle, Renewable Energy, Oxford University Press (2004)
Global Primary Energy Sources 2002
6
Boyle, Renewable Energy, Oxford University Press (2004)
Renewable Energy Use – 2001
7
Boyle, Renewable Energy, Oxford University Press (2004)
Tidal Power
8
Tidal Motions
9
Boyle, Renewable Energy, Oxford University Press (2004)
Tidal Forces
10
Boyle, Renewable Energy, Oxford University Press (2004)
Natural Tidal Bottlenecks
11
Boyle, Renewable Energy, Oxford University Press (2004)
Tidal Energy Technologies
1. Tidal Turbine Farms
2. Tidal Barrages (dams)
12
1. Tidal Turbine Farms
13
Tidal Turbines (MCT Seagen)
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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
MCT Seagen Pile
14
http://www.marineturbines.com/technical.htm
Tidal Turbines (Swanturbines)

Direct drive to generator


Gravity base


No gearboxes
Versus a bored foundation
Fixed pitch turbine blades


Improved reliability
But trades off efficiency
15
http://www.darvill.clara.net/altenerg/tidal.htm
Deeper Water Current Turbine
16
Boyle, Renewable Energy, Oxford University Press (2004)
Oscillating Tidal Turbine



Oscillates up and down
150 kW prototype
operational (2003)
Plans for 3 – 5 MW
prototypes
http://www.engb.com
17
Boyle, Renewable Energy, Oxford University Press (2004)
Polo Tidal Turbine
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

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
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Vertical turbine blades
Rotates under a
tethered ring
50 m in diameter
20 m deep
600 tonnes
Max power 12 MW
18
Boyle, Renewable Energy, Oxford University Press (2004)
Power from Land Tides (!)
19
http://www.geocities.com/newideasfromtelewise/tidalpowerplant.htm
Advantages of Tidal Turbines

Low Visual Impact


Low Noise Pollution


Sound levels transmitted are very low
High Predictability


Mainly, if not totally submerged.
Tides predicted years in advance, unlike wind
High Power Density

Much smaller turbines than wind turbines for the
same power
20
http://ee4.swan.ac.uk/egormeja/index.htm
Disadvantages of Tidal Turbines




High maintenance costs
High power distribution costs
Somewhat limited upside capacity
Intermittent power generation
21
2. Tidal Barrage Schemes
22
Definitions

Barrage


Flood


An artificial dam to increase the depth of water for
use in irrigation or navigation, or in this case,
generating electricity.
The rise of the tide toward land (rising tide)
Ebb

The return of the tide to the sea (falling tide)
23
Potential Tidal Barrage Sites
Only about 20 sites in the world have been identified as possible tidal barrage stations
24
Boyle, Renewable Energy, Oxford University Press (2004)
Schematic of Tidal Barrage
25
Boyle, Renewable Energy, Oxford University Press (2004)
Cross Section of a Tidal Barrage
26
http://europa.eu.int/comm/energy_transport/atlas/htmlu/tidal.html
Tidal Barrage Bulb Turbine
27
Boyle, Renewable Energy, Oxford University Press (2004)
Tidal Barrage Rim Generator
28
Boyle, Renewable Energy, Oxford University Press (2004)
Tidal Barrage Tubular Turbine
29
Boyle, Renewable Energy, Oxford University Press (2004)
La Rance Tidal Power Barrage




Rance River estuary, Brittany (France)
Largest in world
Completed in 1966
24×10 MW bulb turbines (240 MW)
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5.4 meter diameter
Capacity factor of ~40%
Maximum annual energy: 2.1 TWh
Realized annual energy: 840 GWh
Electric cost: 3.7¢/kWh
30
Boyle, Renewable Energy, Oxford University Press (2004)
Tester et al., Sustainable Energy, MIT Press, 2005
La Rance Tidal Power Barrage
31
http://www.stacey.peak-media.co.uk/Brittany2003/Rance/Rance.htm
La Rance River, Saint Malo
32
La Rance Barrage Schematic
33
Boyle, Renewable Energy, Oxford University Press (2004)
Cross Section of La Rance Barrage
34
http://www.calpoly.edu/~cm/studpage/nsmallco/clapper.htm
La Rance Turbine Exhibit
35
Tidal Barrage Energy Calculations
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
  0.33 = capacity factor (20-35%)
E  mgR / 2   ( AR) gR / 2
E  1397R A kWh per tidal cycle
2
Assuming 706 tidal cycles per year (12 hrs 24 min per cycle)
E yr  0.997 10 R A
6
2
36
Tester et al., Sustainable Energy, MIT Press, 2005
La Rance Barrage Example
 = 33%
R = 8.5 m
A = 22 km2
E yr  0.997  10 6R 2 A
E yr  0.997  10 (0.33)(8.5 )( 22)
6
2
E yr  517 GWh/yr
37
Tester et al., Sustainable Energy, MIT Press, 2005
Proposed Severn Barrage (1989)
Never constructed, but instructive
38
Boyle, Renewable Energy, Oxford University Press (2004)
Proposed Severn Barrage (1989)

Severn River estuary
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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)
39
Severn Barrage
Layout
40
Boyle, Renewable Energy, Oxford University Press (2004)
Severn Barrage Proposal
Effect on Tide Levels
41
Boyle, Renewable Energy, Oxford University Press (2004)
Severn Barrage Proposal
Power Generation over Time
42
Boyle, Renewable Energy, Oxford University Press (2004)
Severn Barrage Proposal
Capital Costs
~$15 billion
(1988 costs)
43
Boyle, Renewable
Tester
et al., Sustainable
Energy,Energy,
OxfordMIT
University
Press, Press
2005 (2004)
Severn Barrage Proposal
Energy Costs
~10¢/kWh
(1989 costs)
44
Boyle, Renewable Energy, Oxford University Press (2004)
Severn Barrage Proposal
Capital Costs versus Energy Costs
1p  2¢
45
Boyle, Renewable Energy, Oxford University Press (2004)
Offshore Tidal Lagoon
46
Boyle, Renewable Energy, Oxford University Press (2004)
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
47
Boyle, Renewable Energy, Oxford University Press (2004)
Promising Tidal Energy Sites
Country
Location
TWh/yr
GW
Canada
Fundy Bay
17
4.3
Cumberland
4
1.1
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
USA
Korea
10
Australia
5.7
1.9
48
http://europa.eu.int/comm/energy_transport/atlas/htmlu/tidalsites.html
Tidal Barrage Environmental Factors

Changes in estuary ecosystems

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Less turbidity – clearer water

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More light, more life
Accumulation of silt


Less variation in tidal range
Fewer mud flats
Concentration of pollution in silt
Visual clutter
49
Advantages of Tidal Barrages

High predictability

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Similar to low-head dams

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Tides predicted years in advance, unlike wind
Known technology
Protection against floods
Benefits for transportation (bridge)
Some environmental benefits
50
http://ee4.swan.ac.uk/egormeja/index.htm
Disadvantages of Tidal Turbines



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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
51
Wave Energy
52
Wave Structure
53
Boyle, Renewable Energy, Oxford University Press (2004)
Wave Frequency and Amplitude
54
Boyle, Renewable Energy, Oxford University Press (2004)
Wave Patterns over Time
55
Boyle, Renewable Energy, Oxford University Press (2004)
Wave Power Calculations
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
2
s e
H T
P
2
Example: Hs2 = 3m and Te = 10s
H T 3 10
kW
P

 45
2
2
m
2
s e
2
56
Global Wave Energy Averages
Average wave energy (est.) in kW/m (kW per meter of wave length)
57
http://www.wavedragon.net/technology/wave-energy.htm
Wave Energy Potential

Potential of 1,500 – 7,500 TWh/year



200,000 MW installed wave and tidal energy power
forecast by 2050

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10 and 50% of the world’s yearly electricity demand
IEA (International Energy Agency)
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.”
58
http://www.wavedragon.net/technology/wave-energy.htm
Wave Energy Technologies
59
Wave Concentration Effects
60
Boyle, Renewable Energy, Oxford University Press (2004)
Tapered Channel (Tapchan)
61
http://www.eia.doe.gov/kids/energyfacts/sources/renewable/ocean.html
Oscillating Water Column
62
http://www.oceansatlas.com/unatlas/uses/EnergyResources/Background/Wave/W2.html
Oscillating Column Cross-Section
63
Boyle, Renewable Energy, Oxford University Press (2004)
LIMPET Oscillating Water Column

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Completed 2000
Scottish Isles
Two counter-rotating
Wells turbines
Two generators
500 kW max power
64
Boyle, Renewable Energy, Oxford University Press (2004)
“Mighty Whale” Design – Japan
65
http://www.jamstec.go.jp/jamstec/MTD/Whale/
Might Whale Design
66
Boyle, Renewable Energy, Oxford University Press (2004)
Turbines for Wave Energy
Turbine used in Mighty Whale
67
Boyle, Renewable Energy, Oxford University Press (2004)
http://www.jamstec.go.jp/jamstec/MTD/Whale/
Ocean Wave Conversion System
68
http://www.sara.com/energy/WEC.html
Wave Conversion System in Action
69
Wave Dragon
Wave Dragon
Copenhagen, Denmark
http://www.WaveDragon.net
Click Picture for Video
70
http://www.wavedragon.net/technology/wave-energy.htm
Wave Dragon Energy Output
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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.
71
http://www.wavedragon.net/technology/wave-energy.htm
Declining Wave Energy Costs
72
Boyle, Renewable Energy, Oxford University Press (2004)
Wave Energy Power Distribution
73
Boyle, Renewable Energy, Oxford University Press (2004)
Wave Energy Supply vs. Electric Demand
74
Boyle, Renewable Energy, Oxford University Press (2004)
Wave Energy
Environmental Impacts
75
Wave Energy Environmental Impact
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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
76
Boyle, Renewable Energy, Oxford University Press (2004)
Wave Energy
Summary
77
Wave Power Advantages

Onshore wave energy systems can be incorporated
into harbor walls and coastal protection

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Create calm sea space behind wave energy
systems

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Reduce/share system costs
Providing dual use
Development of mariculture
Other commercial and recreational uses;
Long-term operational life time of plant
Non-polluting and inexhaustible supply of energy
78
http://www.oceansatlas.com/unatlas/uses/EnergyResources/Background/Wave/W2.html
Wave Power Disadvantages

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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
79
http://www.oceansatlas.com/unatlas/uses/EnergyResources/Background/Wave/W2.html
Wave Energy Summary

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
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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
80
http://www.oceansatlas.com/unatlas/uses/EnergyResources/Background/Wave/W2.html
Future Promise
81
World Oceanic Energy Potentials (GW)
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Source
Tides
Waves
Currents
OTEC1
Salinity
World electric2
World hydro
1 Temperature
2 As
gradients





Potential (est)
2,500 GW
2,7003
5,000
200,000
1,000,000







3
4,000
Along coastlines

4
Practical (est)
20 GW
500
50
40
NPA4
2,800
550
Not presently available
of 1998
82
Tester et al., Sustainable Energy, MIT Press, 2005
Solar Power – Next Week
83
http://www.c-a-b.org.uk/projects/tech1.jpg