Tidal Power
Methods of Extraction
Patrick Dunlap
Definition and Motivation

What is Tidal Energy?


Energy contained in a tide, especially that which can
be converted to electricity.
Why Tidal Energy?

Declining availability of fossil fuels and global
climate change.
Tidal Theory

Energy Source

Tidal Cycle

Amplitude
Traditional Method

Harnesses Potential
Energy within tide
Current Plants
Country
Site
Installed
Power (MW)
Basin Area
(km2)
Mean Tide (m)
France
La Rance
240
22
8.55
Russia
Kislaya Guba
.4
1.1
2.3
Canada
Annapolis
18
15
6.4
China
Jiangxia
3.9
1.4
5.08
Disadvantages

Environmental

Economical

Design
New Method

Involves extraction of
kinetic energy from a tide,
given in KE Flux

Mechanical processes for
extraction are based on the
hydrofoil.
Actual Power Output


Energy Flux equation is
multiplied by a Constant
Cp
The differential dA is
now representative of the
sweep are of the blades
Site Selection



High average velocity
(currently looking at > 3
m/s)
High local energy
demand
Within Current
Technical Limits
Comparison to Wind

Advantages




Density
Predictability
Aesthetics
Disadvantages


Scale
Construction
Current Projects



In August SeaGen, a 1.2
MW, dual turbine unit
will be connected to the
power grid
2.25 MW turbine will
supply Portugal
Last December two
turbines installed in NY’s
East River
References





Tidal Energy, AM Gorlov, 2001
Choosing and Evaluating sites for Tidal Energy
Evaluation, Byrden, Proceeding of the Institute of
Mechanical Engineers, V 218
Tapping the Power of the Seas, Economist, V383
Tidal Current Energy Extraction: Hydrodynamic
Resource Evaluation, Couch, Proceeding of the
Institute of Mechanical Engineers, V 220
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