OCEN 201
Introduction to Ocean &
Coastal Engineering
Renewable Marine Energy (2)
Jun Zhang
jzhang@civil.tamu.edu
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Cost of Ocean Energy
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<Carbon Trust Report, 2006>
Status of Ocean Energy Technologies
 Current Status
 Demonstration scale
 Issues
 Design and Maintenance:
1) Robustness and efficiency of energy
 Cost estimate from 20-75cents/kWh for
generator
WEC and 5-30cents/kWh for TEC. More
2) Corrosion and survivability
realistic estimation may be at its high end
3) Economics
 More Research is needed not more
 Environmental impacts: ecology (e.g.
hype
Shiwa tide power plant)
 Transmission: Integration into the grid
(intermittent energy generation and long
distance)
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 Storage of Energy
Ocean Energy Development in US
Program Areas and Funding
(Courtesy of Mr. Hoyt Battey, US DOE)
 Water Program Restarted in FY 2008
FY07
FY08
FY09
FY10
Recovery Act
$0M
$10M
$40M
$40M - $60M?
$32M
Appropriations address both conventional hydro (CH) and marine and hydrokinetic
technologies (MHK)
Recovery Act focused on conventional hydropower for short-term impacts
Technology Definitions
Marine and Hydrokinetic (MHK): energy from:
• Waves
• Water currents (tides, rivers, ocean currents, man-made channels)
• Ocean thermal energy (OTEC)
Development in US
FY09 Water Budget Allocation
Conventional
Hydro TD,
$4.10, 11%
Marine &
Hydrokinetic
MA, $10.44,
28%
FY2009 Water Budget $37.6M
Marine &
Hydrokinetic
TD, $15.55,
41%
Conventional
Hydro MA,
$4.86, 13%
Program
support, $2.66,
7%
 Technology Development: Address technical barriers to device design, development,
testing, and integration
 Market Acceleration: Address non-technical barriers to development, siting, and
deployment
MHK Program Priorities
Development in US
• System Deployment and Testing
– Facilitate the deployment and testing of full scale MHK prototypes and components
– Support the development of integrated test centers
– Generate data on performance, reliability and impacts
• Cost Reduction and System Performance/Reliability
– Support design and development of scale systems and components
– Develop design and testing protocol, support developers who follow it
• Understand Environmental Effects
– Collect/disseminate data on environmental impacts to reduce deployment costs and
environmental effect
• Resource Assessments
– Determine the available, extractable, and cost-effective water resources in the US
• Develop Evaluation and Performance Standards
– Characterize, evaluate and compare the wide variety of MHK technologies; continue
IEC/IEA standards development
Development in US
FY2008 MHK Projects
Technology Development Projects
 2008 Funding Opportunity Announcement, Topic Area 1: Advanced
Water Power Renewable Energy In-Water Testing and Development
Projects
– WaveConnect Wave Energy In-Water Testing and Development Project
(Pacific Gas & Electric Company)
– Development and Demonstration of an Oscillating Water Column (OWC)
Power System (Concepts ETI, Inc).
– Improved Structure and Fabrication of Large, High-Power Kinetic
Hydropower Systems and Rotors (Verdant Power Inc).
– Puget Sound Tidal Energy In-Water Testing and Development Project
(Snohomish County PUD)
– Advanced Composite OTEC Cold Water Pipe Project (Lockheed Martin)
– Northwest National Marine Renewable Energy Center (OSU/UW)
– National Marine Renewable Energy Center in Hawaii (U of Hawaii)
Development in US
FY2008 MHK Projects
Market Acceleration Projects
 2008 Funding Opportunity Announcement, Topic Area 2: Marine and
Hydrokinetic Renewable Energy Market Acceleration Projects
– Guidelines for Developers and a Framework for Siting Marine and
Hydrokinetic Energy Projects (Pacific Energy Ventures, re vision, PCCI)
– Wave Resource Assessment (Electric Power Research Institute -- EPRI)
– Tidal Resource Assessments (Georgia Tech Research Corporation)
– International Standards Development for Marine and Hydrokinetic
Renewable Energy (Science Applications International Corporation)
 Report to Congress: Potential Environmental Effects of Marine and
Hydrokinetic Energy Technologies
 International Energy Agency, Ocean Energy Systems (IEA-OES) Annex
IV, Assessment of Environmental Effects and Monitoring Efforts for
Ocean Wave, Tidal, and Current Energy Systems
 Jobs and Economic Development Index (JEDI) modeling
Development in US
FY2009 Funding Opportunities
Industry-led Projects
 Topic Area 1: MHK Energy Conversion Device or Component Design and
Development
 Topic Area 2: MHK Site-specific Environmental Studies and Information
 Topic Area 3: Advanced Water Power Market Acceleration Projects/Analysis
and Assessments
Laboratory-led Projects
 Topic Areas 1 & 3: Supporting Research and Testing (MHK, CH)
– Computational tools/models to predict device/array behavior; advanced materials,
device testing and validation codes
 Topic Areas 2 & 4: Environmental Assessment and Mitigation Methods
– Tools and studies to predict, evaluate, and minimize environmental impacts
Barriers and Actions to Overcome
Despite the increased interest and research and development activities, ocean energy
technologies remain high risk and at an early stage of development.
Several technical and non-technical barriers are currently restricting development of
ocean energy technologies.
–Lack of sufficient demonstration of prototypes in the marine environment
–Cost of connecting ocean energy systems to electricity networks impacts on demonstration
projects
–Lack of understanding on environmental impacts
–Absence of internationally recognized standards for development, testing and
measurement
Ocean energy technology could contribute to meeting cost-effective, sustainable and
secure energy demands in the long term provided governments and device developers
act to overcome the barriers identified and reduce the high cost and high risk
associated with these
technologies.
Resources
Wave Energy Resource Distribution
2,000TWh/year of energy, the equivalent of 10% of the world electricity
consumption, could be harvested from the world’s oceans (CRES, 2006)
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Estimate of Wave Energy Resource
• Wave Energy Density
1
1
2
E 
 gA   gH 2
2
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Average wave energy per unit area it has unit (work/per unit area)
N-m/m2 (J/m2 ),or lb-ft/ft 2
•Wave Energy Flux through unit length at ocean surface
F  EC g
(Jole/s/m, W/m)
C g     Wave Group Velocity
•Wave Energy Resource (Energy Flux * Time per unit length)
Time of the wave at this height (per year) and per length of
the wave field normal the wave direction, kw*hr/m/year
Example of Estimating Wave Energy Resource
Near a coast area, the year-long wave characteristics are described below
Jan - Mar
H1 = 5 m, T1 = 10s
Apr - Jun
H 2 = 4 m, T2 = 8s
July - Sept
H3 = 3 m, T3 = 6s
Oct - Dec
H 4 = 6 m, T4 = 12s
What is Wave energy resource per unit length at this area?
1
Jan - Mar
E1   gH12  31.56 kN  m / m 2
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Assuming deep water C g1  7.81 m / s
Energy Flux per unit length = E1 *C g1  246.5 kw / m
In three months (, the total energy flux per unit length
246.5kw / m *90 (days)*24 (hr)  5.324*105 kwhr / m
Example of Estimating Wave Energy Resource
Near a coast area, the year-long wave characteristics are described below
Jan - Mar
H1 = 5 m, T1 = 10s
Apr - Jun
H 2 = 4 m, T2 = 8s
July - Sept
H 3 = 3 m, T3 = 6s
Oct - Dec
H 4 = 6 m, T4 = 12s
What is Wave energy resource per unit length at this area?
Apr-Jun
E2  20.2 kN  m / m 2 , in deep water C g 2  6.25 m / s
Energy Flux per unit length = E2 *C g 2  126.3 kw / m
126.3 kw / m *91 (days) * 24 (hr)  2.757 *105 kwhr / m
July-Sept
E3  11.36 kN  m / m 2 , in deep water C g 3  4.68 m / s
Energy Flux per unit length = E3 *C g 3  53.21 kw / m
53.21 kw / m *92 (days) * 24 (hr)  1.175*105 kwhr / m
Example of Estimating Wave Energy Resource
Oct-Dec
E4  45.45 kN  m / m 2 , in deep water C g 4  9.37 m / s
Energy Flux per unit length = E4 *C g 4  425.8 kw / m
425.8 kw / m *92 (days)*24 (hr)  9.402*105 kwhr / m
Hence, each year, Energy Flux per unit length = 5.324*105 
2.757*105  1.175*105  9.402*105  1.866*106 kwhr / m per year
Average Energy Flux over unit length
1.866*106 kwhr / m / (365*24 hr )  213.0 kw / m
If the wave field is 10 km wide, then the wave energy at this area
per year is equal to 1.866*1010 kwhr per year.
Storage (and Transport) of Renewable Energy
Because renewable energy such as wind, wave and current
energy, in general is not steady, the issue of storage of their
energy become an important issue. The benefits of storage are
significant, especially in integrating distributed power
generation. Storage protects against mistakes in forecasting,
removes barriers in connecting renewable sources to a variety of
grids, shifts demand peaks by storing off-peak energy to sell
back to the grid during peak times, provides frequency regulation
and deters expensive grid upgrades.
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Storage of Renewable Energy
The followings are a few ideas
1. Large Battery System (High Performance Hydroxyl
Conductive Membrane For Advanced Rechargeable Alkaline
Batteries, High Energy, Low Temperature Rechargeable
Battery for Load Leveling Application, & Nanostructured
Cathode for Magnesium Ion batteries)
2. Compress Air (For example, pumping pressured air into a
massive case for storage)
http://www.physorg.com/news188048601.html
http://www.youtube.com/watch?v=dGd7PIC09AM
3. Grid-scale Storage Project (pumping hydropower
http://www.youtube.com/watch?v=iFdVX0NIPDE )
Storage of Renewable Energy
4. Superconducting Magnetic Energy Storage
http://www.youtube.com/watch?v=QU05d43dw6g
5. Combination the renewable energy device with other large
energy consumption device (not only for storage but also saving
transport cost)
1.
Fuel Cell (use spare energy to produce Hydrogen & Oxygen
from water)
2. Desalination of sea water using renewable energy
http://www.youtube.com/watch?v=bIrXKyWF8Nw
3. Storage thermal energy (ice water, hot water and melting
salts)
4. Liquefy natural gas or industries consuming heavy power
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Economic Assessment of RE Devices
The successful commercial deployment of all kinds of RE
(renewable energy) devices depends on the cost.
The following is an example of the cost of a fixed offshore wind
turbine.
The figure shows the breakdown of total system cost
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Economic Assessment of RE Devices
Items in the total cost
1)
2)
3)
4)
5)
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Support Structure (24%)
Wind Turbine (33%)
Grid Connection (Cable) (15%)
O&M (operation and Maintenance) (23%)
Others (5%)
Storage Examples
http://www.youtube.com/watch?v=RlfDXAuhjwU
http://www.youtube.com/watch?v=JgmbPf1Jd-8
http://www.youtube.com/watch?v=hCywnjG9tes&feature=re
lated
http://www.youtube.com/watch?v=Ra5WTItC0_4
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