Tide EnergyTechnologies

San Jose State University

FX RongèreApril 2009

Tidal Dams

Tidal Dam

The dam creates a difference of potential energy between the tide pond and the open sea

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Power Generation

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Power Generation

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Power Generation

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With:

τ : tidal period

η : Turbine conversion rate

AT: Area of the turbine

R : Range of the tide

Apool: Area of the tidal pool

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Basin Management

To optimize power generation the flow gates are kept closed some time after high and low tides Tide and Basin Management

La Rance

0

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6

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10

12

0 4 8 12 16 20 24

Time (hour)

Wat

er lev

el (m

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wer

(M

W)

Sea Level

Basin Level

Power

La Rance Tidal Power Plant

Tide mean range: 8.4m Tide basin area: 22 km2

10 m9 m8 m7m6m5m4m3m

La Rance Tidal Power Plant

24 Units of 10 MW each built between 1961 and 1967

700 m dam 480 GWh/y CF=23%

The Severn Barrage (UK) Capacity: 8,640 MW, 17 TWh, CF= 23%,

Length=15.9 km

In the Bristol Channel Range 8.2 m, Basin Area: 480 km2

The Severn Barrage (UK)

Economics

Severn Barrage costsMM MM

Civil Engineering 4,900£ 9,800$ Power Generation 2,400£ 4,800$ Power Control 380£ 760$ Management 300£ 600$ Land sea defences 30£ 60$ Effluent Discharge 80£ 160$

Total 8,090£ 16,180$ Additional cost (Grid) 1,230£ 2,460$

Total investment cost 9,320£ 18,640$ Annual Maintenance cost 70£ 140$ Generation 17 TWhAnnual Revenues ($60/MWh) 595£ 1,190$ Simple Payback Period 15 years

The Severn Barrage (UK)

Current Turbines

Power Curve

Similar to a wind turbine

Source: Source: George Hagerman Tidal Stream Energy in the Bay of Fundy, Energy Research & Development Forum 2006Antigonish, Nova Scotia 25 May 2006

Generation prediction Combining Power curves and current data,

we can calculate the generated power

Turbine main components

Rotor• Extracts power from flow• Turns at low RPM 10-30

rpm• Conversion rate varies

with flow velocity (45% max)

Gearbox• Increase rotational speed

of shaft from turbine• 80-95% efficient

Foundation• Secure turbine to seabed• Resist drag on support

structure and thrust on rotor

Generator and Power Conditioning• Generate electricity• Condition electricity

for grid interconnection

• Turns at high RPM• 95-98% efficient

Source: Brian Polagye Tidal In-Stream Energy Overview March 6, 2007

General concept is similar to wind turbines

Turbines

2...

3vAW TT

η is the conversion rate of the turbine, typically 25% to 35%

300 kW, 6 m prototype developed by Marine Current Technologies in operation in the Bristol Channel since 2003

1 MW, 20m twin rotor prototype currently developed by Marine Current Technologies installed in Northern Ireland’s Strangford Lough (2008)

Marine Current Technologies

Strangford Lough project

Strangford Lough project

Installed in April 2008

Turbines

Verdant Power

35 kW, 5m Diameter turbine developed by Verdant. Prototype installed in New York at Roosevelt Island (2006 2008). Project of 175 kW

Results

7,000 hours of operationElectricity generationRotor damageNo fish collision

Turbines

Lunar Energy2 MW, 21m 7 blade rotor prototype currently in development

Gravity Foundation: concrete slab

Power augmentation by convergent-divergent ducting to increase conversion rate

Promising since 2

...3v

AW TT

On the 11th March 2008 Lunar Energy signed a Memorandum of Understanding with Hyundai Samho Heavy Industries (HSHI) and Korean Midland Power (KOMIPO) to develop the 1MW RTT unit for deployment into Korean coastal waters

Turbines

Clean Current Pile Mounted 4 bladed, 14 m, 1 MW A 65 kW prototype has

been Tested at Race Rocks from Sep 2006 to May 2007

Race Rock is a marine reserve run by Lester B.Pearson College on Vancouver Island (Canada)

Clean Current Turbine

Turbines

Open Hydro Open Center

Rotor Diameter 15 m rated at 1.5 MW

Operating Conditions: Current speed > 0.7 m/s Prototype under test at European Marine Energy Center (UK) – Dec. 2006

April 2009: Contract with Snohomish County Public Utility District (SnoPUD), to develop a tidal energy project in the Admiralty Inlet region of the Puget Sound

Turbines

Gorlov Different mounting

Prototype has been tested at Uldomok Strait in Korea in 2002

1 m diameter and 2.5 m high 1.5 kW

Turbines

Enemar KoboldMoored – surface mounted3 vertical articulating blades vertical: 5.0 m diameter: 6 m chord: 0.4 m25 kW @ 2.0 m/sPrototype has been deployed in Straits of Messina 4 years operational experience

Turbines

Barry Davis’ vertical axis turbine

Source: http://www.bluenergy.com/technology.html

Turbines

Blue Energy Project

Philippine Dalupiri 2200 MW Blue Energy Project

Turbines

The Energy Business Limited

Foundation TechnologiesMonopile

• Small footprint• Established technology

used in offshore wind

Gravity Base

Chain Anchors

Tension Leg

Hollow steel pile driven or drilled into seabed

Pros:

• High cost in deep water• Installation expensive

for some types of seabed

Cons:

Heavy foundation of concrete and low cost aggregate placed on seabed

• Deep water installation feasible

Pros:

• Large footprint• Scour problems for some

types of seabed• Decommissioning

problems

Cons:

• Small footprint• Deep water

installation feasible

Chains anchored to seabed and turbine

Pros:

• Problematic in practice• Device must have high

natural buoyancy

Cons:

Submerged platform held in place by anchored cables under high tension

• Small footprint• Deep water

installation feasible

Pros:

• Immature technology now being considered for offshore wind in deep water

Cons:

(10-40m)

Source: Brian Polagye Tidal In-Stream Energy Overview March 6, 2007

Projects Worldwide

Gulf Stream Current

Gulf Stream Current

Florida Current Resource

Florida Current Resource

2..

3vAW Max

1.9 2.4 2.8 3.1Current speed (knots)

Companies to follow Blue Energy Canada Clean Current Technology Marine Current Turbines GCK (Gorlov) Lunar Energy Open Hydro Enemar Kobold Verdant Power Seapower Tidal Electric Aquantis

Annapolis Tidal Generating Station (USA)