Tidal_Report_06-10-06.pdf

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EPRI TP-008-NA

North America Tidal In-Stream Energy Conversion Technology Feasibility Study

Roger Bedard, Ocean Energy Leader, EPRI;Mirko Previsic ; Br ian Polagye, Univ. of Wash; George Hagerman, Virginia Tech;

Andre Casavant , Devine Tarbel l and Assoc iates

June 11, 2006

AbstractAn Electric Power Research Institute (EPRI)study investigated the techno-economics of in-stream tidal energy conversion (TISEC) and,based on study results, recommends TISECtechnology be evaluated at as a potential energysupply source to diversify and balance theenergy supply portfolio of North America.

A group was out fishing under the Golden GateBridge and noticed that they had drifted west intothe ocean. A young boy asked why. An older manpointed up at the moon and down at the water thatwas pushing them west and said it is the moonpulling water towards it. The boy did not believehim. Then the older man said engineers know howto build machines to use the energy in the movingwater of the tides to make electricity. This time, theboy did believe the man and said when I grow up Iwant to be an engineer and make clean electricityfrom the tides for all the peoples of the world.

The boy recognized that it would be wonderful toget energy from a resource as clean and pollutionfree as ocean tides. The technology, though young,exists to convert the power of ocean tides intoelectricity, the life blood of our society.

Existing tidal power plants include a 240 MW plantin France, a 20 MW plant in Nova Scotia and a 0.5MW plant in Russia. These existing plants usedams to impound the tidal waters before releasingthem through generators to convert the potentialenergy of the elevated water to electricity similar toconventional hydroelectric plants.

In 2005, the Electric Power Research Institute(EPRI) evaluated the techno-economic feasibility oftidal in-stream energy conversion (TISEC) in North

America. TISEC devices are placed in the flowingtidal stream and harness the kinetic energy of themoving water. They do not require a dam orimpoundment of any type.

Seven states and provinces in North Americaparticipated in this EPRI collaborative feasibilitystudy; namely: Alaska, Washington, California,

Massachusetts, Maine, New Brunswick and NovaScotia. Cash and in kind funding support wasprovided by state energy agencies, the USDepartment of Energy through the NationalRenewable Energy Laboratory, utilities in thosestates and the worldwide TISEC developmentcommunity. Key organizations that participated inthe EPRI collaborative are shown in Figure 1.

Figure 1. Collaborative Participants

The Benefits of TISEC Technology

Using tidal in-stream energy to generate electricitywould provide many far-reaching benefits to North

America. The primary benefit is that theconstruction, installation, operation, andmaintenance of tidal power plants would create

jobs, promote economic development, and improveenergy self-sufficiency.

There are many compelling arguments for the useof tidal in-stream energy conversion technology.First, with proper siting, converting tidal in-stream

Federal (4)U.S. DOE

NRELBonneville Power

ACOA

Utilities (12)Bangor Hydro

Central Maine PowerNational Grid

NSTARNB Power

Saint John ElectricNS Power

Anch orage Mu niChugach ElectricTacoma Power

Puget Sound EnergyPG&E

Provincial/State/CityAgenc ies (8)

Maine Tech InitiativeMass Tech CollaborativeNew Brunswick Ministry

Nova Scotia MinistryAlask a Energy Auth ori ty

Washington CTEDSan Francisco &

Oakland CA

Tidal Power Developers(8)

GCKLunar Energy

Marine Current TurbinesOpen HydroSeapower

SMD HydrovisionUEK

Verdant

Institutes (3)Virginia Tech ARI

Bedford Inst. Oceanogr.Univ. Maine Orono

EPRI PROJECTEPRI

M. PrevisicGordon Fader

Global Energy PartnersDevine Tarbell

NRELVa Tech

Univ of WAME PUC

Pro osed Plant submer ed and not visible


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EPRI TP-008-NA A Feasibility Study of In Stream Tidal Energy Conversion Technology in North America

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energy to electricity is believed to be one of themore environmentally benign ways to generateelectricity. Second, since kinetic energy is afunction of the density of the moving mass and itsspeed and water has high density, the powerdensity of the tidal resource is high. Third, in-stream tidal energy offers a way to minimize theaesthetic issues that plague many energy

infrastructure projects, from nuclear to coal and towind generation. Since most TISEC devices aretotally submerged they are not visible. Althoughvariable in power level like many other renewableresources, tidal energy is predictable and thereforecan be more easily integrated into the electricitygrid for providing reliable power. Since a balancedand diversified portfolio of energy sources is thebedrock of a robust electricity system, tidal energyis consistent with North Americas energy needsand goals. In-stream tidal energy is an importantenergy source and deserves a fair evaluation of itspotential to add to the energy supply mix of North

America.

A relatively minor investment today might stimulatea worldwide industry generating billions of dollars ofeconomic output and employing thousands ofpeople while using an abundant and clean naturalresource.

Description of Study Technical Approach

EPRI feasibility studies use a systems approach(see Figure 1). The tidal study began with twoparallel tasks; a survey of the potential sites in

terms of a dozen or so attributes which make agood tidal site and a survey of the worldwide TISECdevice technology.

State and provincial advisors selected a specific siteand device for a techno economic feasibility study.The site selection results in how much energy is

available to be extracted and the device selectionresults in the efficiency of extracting that energy.The EPRI Project Team designed a plant system,calculated its annual energy output, estimated itscost both initial installed and yearly operation andmaintenance, and calculated the levelized busbarcost of electricity (cents per kWhr) as described inEPRI performance and cost assessment

methodology reports (Ref: 1 and 2).

Description of Sites

A good in-stream tidal site is one that has a largeamount of fast moving water, has bathymetry andseabed properties that will allow a TISEC device tobe sited, has minimum or no conflicts with otheruses of the sea space and is close to a load andgrid interconnection. EPRI surveyed potential sitesin Massachusetts, Maine, New Brunswick andNova Scotia and documented that work in fourEPRI TP 003 reports (Ref: 3 - 6). In Alaska,

Washington and California, the site and device waspre-selected. The seven (7) feasibility evaluationsites are shown in Figure 3 and described in thetable below.

Figure 3. Tidal Sites in EPRI Feasibility Study

AK WA CA MA ME NB

CrossSection

Area (m2)

72,500

62,600 74,700 17,500 36,000 60,000 22

PowerDensity(kW/m2)

1.6 1.7 3.2 0.95 2.9 0.7-2

Avallable

Power(MW) 116 106 237 13.3 104 43-100 1

ExtractPower(MW)

17.4 16 35.5 2.0 15.6 6.5-15

# HomesPowered

12,000

11,100 27,300 1,500 12,000

5,000-11,500

117

Power is average annual; extractable power is limited to 15% ofavailable power; assumed 90% power take off efficiency

Number of homes powered assumes 1.3 kW per average homeNB and NS power estimates have a higher degree of uncertainty th

US sites due to lack of measurement stations in Canada

Knik Arm

MinasPassage NS

Western Passage

MuskegetChannel MA

Head HarborPassage NB

Golden GateCA

TacomaNarrows WA

Site Survey003 Reports

Available TidalCurrent Power

001 Report

Extracted Power001 Report

Maximum AnnualOutput on001 Report

Actual AnnualOutput

Final Design andEconomic

AssessmentRe orts 006 Re ort

Cost andEconomics

Methodology002 Report

Device Survey004 Report

Tidal Current Power

Extraction Efficienc

Power ChainEfficiency

Availability

O&M Costs

Capital Costs

SystemDesign

Methodology005 Report

MethodologyReports

Design, Perf, Costand Econ Reports

Final Summary008 Report

Env and Reg Issues007 Report

Figure 2. Feasibility Study Technical

Survey Report


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Description of TISEC Technology

Tidal energy extraction is complex and manydifferent designs have been proposed. It is helpfulto introduce these in terms of their physicalarrangements and energy conversion mechanisms.Water turbines, like wind turbines, are grouped intotwo types: 1) horizontal axis turbines in which the

axis of rotation is horizontal with respect to theground and parallel to the flow direction and 2)vertical or cross flow axis turbines where the axis ofrotation is perpendicular to the flow direction.Typical subsystems include rotor blades whichconvert the energy in the water to rotational motion,a drive train, usually including a gear box and agenerator that convert the rotational shaft motion toelectrical energy, and a structure that supports therotor and the drive train. Other ways of groupingthese devices include:

Support Structure devices may be either

gravity base bottom mounted, attached to amonopole foundation or anchored and mooredand allowed to fly in the tidal stream.

Open versus shrouded rotors Fixed versus variable pitch blades Yaw control versus fixed yaw angle Drag versus lift water foil (vertical axis only)

Tidal power research programs in industry,government and at universities in the UK, Norway,Ireland, Italy, Sweden, Canada and the US over thelast half dozen years has established an importantfoundation for the emerging tidal power industry.

Today, a number of companies backed by privateindustry, venture capital and EuropeanGovernments are leading the commercialization oftechnologies to generate electricity from tidalstreams. In early 2005, EPRI requested informationfrom all known TISEC device developers. Eight (8)devices were characterized with the objective ofdetermining technology maturity and any criticalissues relating to technological readiness for pilotplant demonstration testing in the 2009 time period(Ref: 7). A summary and photos and illustrations ofthe eight devices in alphabetical order follow:

GCK Lunar MCT OpenHydro

Seapower

SMDHydro

UEK Ver-dant

VaxisLift

HaxisDuct

HaxisDual

HAxis

Rim Gen

VaxisDrag

HaxisDual

HAxisDual

Haxis

1 mdia

21mdia

18 mdia

15 mdia

1 mdia

8 mdia

3 mdia

5 mdia

7kW

2MW

1.5MW

1.5MW

44kW

1MW

400kW

34kW

1) Axis type; 2) Diameter of the rotor and 3) Rated power

EPRI Advisors selected three TISEC devices for thedesign phase of the study: Lunar Energy, MarineCurrent Turbines (MCT) & Verdant Power.

Lunar Energys RTT 2000 is a fully submergedducted turbine with the power conversionsystem inserted in a slot in the duct as acassette. This allows the critical components tobe recovered for operation and maintenance.Lunar performance was estimated (see Ref: 9and 11-15), however, since the engineeringdesign was not completed at the time of thisstudy (Jan- Mar 2006), no cost estimates weremade by EPRI of the RTT 2000.

Marine Current Turbines (MCT) SeaGenconsists of two horizontal-axis rotors and powertrains (gearbox and generator) attached to asupporting monopile by a cross-arm. The entireassembly is called a turbine. The monopile issurface piercing and includes an integratedlifting mechanism to lift the rotors and power

trains out of the water for maintenance. MCTprovided engineering specifications upon whichan EPRI independent cost estimate was made.

Verdant Powers turbine was designed for theEast River in New York and is 5 meters indiameter. This design was judged to be toosmall for the seven sites under study.Furthermore, we judged it inappropriate for EPRIto attempt to scale up the design for costingpurposes.

Figure 4. Gorlov Helical Turbine

Figure 5. Lunar Energy RTT Turbine


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Figure 6. MCT Experimental SeaFlow

Figure 7. MCT SeaGen Prototype

Figure 8. Open Hydo Rim Drive Turbine

Figure 9. Seapower Vertival Axis Turbine

Figure 10. SMD Hydrovision

Figure 110. UEK Shrouded Turbine

Figure 121. Verdant Power RITE Turbines

The purpose of the EPRI study was to assess thetechno-economics feasibility of TISEC technologyand was not to compare individual devicetechnology. EPRI is heartened with the largenumbers of devices and different types of devicesbeing developed. The technology is much tooyoung for anyone to be able to know which of these

technologies will turn out to be the most cost-effective in the future.

Tidal Plant Design, Performance and Cost

For most of the study sites, installation of an arrayof TISEC devices will overlap with existing shippingchannels. As such, only fully submerged devicescan be used in order to allow sufficient overheadclearance for unimpeded navigation. While theMCT SeaGen is surface piercing, the company has


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conceptualized a fully submerged 2nd generationdesign that is patent pending. MCTs 2

ndgeneration

technology consists of 6 rotors mounted on a singlestructure which can be raised to the surface formaintenance using an integrated lifting mechanism,as illustrated in Figure 13. Given similar scale andtechnology used on MCTs 2

ndgeneration fully

submersed technology (same rotor, drive train and

foundation as SeaGen with a modified supportstructure and lifting mechanism), it is likely that costand performance will be similar to the surfacepiercing SeaGen. It is unlikely; however, thatMCTs 2nd generation device would be ready forcommercial pilot demonstration for at least 2 yearsas proof of high reliability is a prerequisite.

Figure 13. MCT Next Generation Concept

Pilot scale (a single device) and commercial scaleplant (sized to extract 15% of the energy from thetidal stream) performance is contained in the tablebelow. The 15% size limit is to preclude anysignificant ecological effect due to the plant and isan estimate from experts in the UK. In two cases

(Golden Gate, California and Western PassageMaine) the 15% extraction limit could not be reachedsince the relatively small high current area limits thenumber of turbines which can be deployed (usingexisting prototype designs). Since both thesechannels are deep, future stacked arrays could allowextraction up to the 15% limit. Those two sites arecolored in yellow below.

AK WA CA MA ME NB NS

Site KnikArm

TacNarrs

GoldenGate

Musk-eget

WestPass

HeadHarbor

MinasPass

Unit RatedPower (MW) 0.76 0.7 1.1 0.46 0.83 0.31 1.11Unit RatedSpeed(m/s) 1.9 1.9 2.1 1.6 2.0 1.4 2.2Unit Avg YrlPower (MW) 0.22 0.21 0.37 0.18 0.38 0.13 0.52# of ComlUnits 66 64 40 9 12 66 250Avg Power(MW) (3) 14.6 13.7 16.5 1.6 4.6 7.3 1301000 HomesPowered 11.2 10.5 12.8 1.3 3.5 6.5 100

(1) Extractable is 15% of available(2) Rated power at rated speed is optimized for lowest COE

(3) 1.3 kW per average U.S. home per IEA(4) Yellowed rows are existing prototype design limited

The EPRI system-level conceptual designs are notdesigns from which a system can be built. Micrositing of each turbine requires 3-D modeling of thesite region with multipoint velocity measurementsfor model calibration.

Conceptual Tidal Plant Economic Assessment

EPRI independently estimated the plant systemcost based on the MCT SeaGen dual 18 mdiameter rotor device design. Using the economicmethodology, financial assumptions and incentivesdescribed in Ref: 2, EPRI calculated the cost ofelectricity (COE) for a taxable utility generator, amunicipal non taxable generator, and the internalrate of return for a taxable non utility generator. Theresults are shown below.

AK WA CA MA ME NB NSSite Knik

ArmTac

NarsGoldenGate

Musk-eget

WestPass

HeadHarbor

MinasPass

Number ofTurbines

66 68 40 9 12 66 250

Total PlantCost ($M)

110 103 90 17 24 68 486

Yrly LevelO&MCosts

4.1 3.8 3.6 0.6 1.0 2.3 18

AnnualEnergy(GWh)

128 121

129 1.5 40 64 1,140

Utility GenCOE

9.2 10.8

9.0 10.6

6.6 -7.6

8.6 -9.9

5.6 -6.5

10.0 -11.7

3.9 -4.6

Muni GenCOE

7.1 -8.4

7.2 -8.4

4.9 -5.6

6.0 -6.7

4.2 -4.8

9.2 -11.2

3.9 -4.6

Non UtilityGen IRR

None None 21% None 34% None 31%

Cost of electricity (COE) in U.S. cents/kWh

The cost of electricity (COE) is defined as the totalplant cost times the fixed charge rate plus theannual operation and maintenance (O&M) alldivided by the annual energy produced. The fixedcharge rate is the percentage of the total plant costthat is required over the project life to cover theminimum annual revenue requirements, and assuch, accommodates the individual state andprovincial tax rate and incentives structure. The

COE for a utility and municipal generator is in therange of 4 12 cents/kWh (2005 US$).

The internal rate of return (IRR) is defined as thediscount rate that sets the present worth of the netcash flows over the project life equal to the equityinvestment at the commercial operating date.Neither Alaska, Washington, Massachusetts norNew Brunswick designs produced a rate of returnfor a non-utility Generator. California, Maine and


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Nova Scotia designs do offer a non-utility generatoran estimated 21 to 34% rate of return on theirinvestment.

TISEC device technology is similar to windtechnology and has benefited from the learningcurve of wind machine production experience, bothon shore and off shore. Therefore, the entry point

for a TISEC plant is much less than that of a windplant back in the late 1970s and early 1980s (i.e.,over 20 cents/kWh). Additional TISEC costreductions will be realized through valueengineering and economies of scale.

The current comparative costs of several differentcentral power generation technologies are givenbelow. We are using generally accepted averagenumbers and ranges from EPRI sources (Ref: 17).The tidal plant capacity factor is a function of thetidal flow profile with capacity factors higher in theEast Coast than on the West Coast because of

large tidal diurnal differences on the West Coast.The tidal plant capital cost is a function of the plantsize, tidal flow profile, the bathymetry and thegeotechnical properties of the seabed. The COE isa function of the power density of the tidal streamand the plant size.

CapacityFactor

(%)

CapitalCost (1)($/MW)

COE(2)(cents/

kWh)

CO2(lbs perMWh)

Tidal In-streamPower Den > 3.0Power Den 1.5-3.0

Power < 1.5 kW/m2

29-46 1.7-2.02.1-2.4

3.3-4.0

4 7. 4 11

. 6 - 12

NoneNone

None

Wind (class 3- 6) 30-42 1.2 1.6 4.7-6.5 None

Solar Thermal Trough 33 3.3 18. None

Coal PC USC (2) 80 1.3 4.2 1760

NGCC @ $5/MM BTU(3)

80 0.5 4.8 860

NGCC @ $7/MM BTU

(3)

80 0.5 6.4 860

IGCC with CO2Capture (4)

80 1.9 6.1 344

(1) All costs in 2005 US$(2) 600 MW Plant, Pittsburgh #8 Coal(3) GE 7 F machine or equivalent(4) 80% removal

Central Power versus Distributed Power

Except for the Minas Passage which has the size tobe considered central power, all other sites studiedin the U.S. and Canada fall in between the classicdefinition of distributed generation (DG) and centralpower generation.

We use the term distributed generation (DG) ordistributed resources (DR) to describe an electricgeneration plant located in close proximity to theload that it is supplying and is either connected tothe electric grid at distribution level voltages orconnected directly to the load. Examples of DG/DR(DR when some form of storage is included) arerooftop photovoltaic systems, natural gas microturbines and small wind turbines. Large windprojects and traditional fossil fuel plants areexamples of central generation where the electricitydelivers power into the grid at transmission voltagelevels.

DG types of systems traditionally find applicationsin niche markets because of unique market driverssuch as:

Delay or defer an upgrade to T&D infrastructurethat would otherwise have been necessary tobring power generated away from a load centerto that load center

Voltage stability support Displace diesel fuel in off grid applications Satisfy local citizens desires to have control of

their own power source

A realistic comparison to equitably evaluate thecost of deferring T&D expenses with the cost ofinstalling DG/DR is complex and requiresconsidering depreciation and tax benefits, propertytax and insurance for both options, maintenanceand fuel costs of operating the DG/DR andemploying discounted cash flow methods. Thiscomparison must be made on a case-by-casebasis.

EPRI Conclusions

U.S. Tidal In-stream Potential

Knik Arm in Alaska, Tacoma Narrows inWashington, Golden Gate in California andWestern Passage in Maine all have good cross-sectional area size (36,000 to 72,000 squaremeters), good power density (1.5 to 3.2 kW/m2)and an interconnection which is easily managed.The Muskeget Channel in Massachusetts issomewhat small (17,500 square meters), low inpower density (0.95 kW/m2) and is not easily


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interconnected to the grid. We found no other goodtidal sites in Massachusetts, except for the CapeCod Canal, which is currently used for shipping withno unused and available cross section for powergeneration.

Canada Tidal In-stream Potential

The available tidal energy potential for the MinasPassage Nova Scotia is over 1 GW. Harnessing

just 15% of the available tidal energy resource basewould generate enough electricity to power about120,000 Canadian homes (assuming an average of1.3 kW per home).

The Head Harbor Passage site, although large insize (60,000 square meters), is low in powerdensity (0.94 kW/m2). Perhaps higher powerdensity sites in the Cumberland Basin or a jointproject with the U.S. in Western Passage might bea future direction for the province.

Sensitivi ty Studies

Sensitivity studies show that the power density andnumber of turbines have a significant effect onCOE. Kinetic power varies as the cube of the tidalcurrent velocity; therefore high velocity tidal streamsites are necessary for economic tidal plants. Fixedcosts, such as mobilization costs, are spread over alarger number of turbines for a large array. Detailsof the sensitivity studies are described in the devicedesign reports (Ref: 9-15)

Technology Development Status

In-stream tidal energy technology is an emergingtechnology with some small scale and somesurface piercing devices now ready for pilotdemonstration testing in the US and Canada. Largescale non-surface piercing devices will be ready forpilot scale demonstration testing in the US andCanada within a year or two. Most sites require nonsurface piercing devices.

The MCT 300 kW experimental prototype has beenoperating in the UK for over 3 years and much hasbeen learned. The 18-month Verdant RooseveltIsland Tidal Energy (RITE) East River NY 200 kW

demonstration project (6 turbines at 34 kW each) isnow licensed and will commence testing in mid-2006. The MCT SeaGen 1 MW commercialprototype is being fabricated (Figure 14) and willalso commence testing in 2006 at Strangford UK;an environmentally sensitive site. Both the Verdantand MCT test programs include extensiveenvironmental and marine life monitoring.

Additional tidal systems including an Open HydroTurbine, a Lunar Energy RTT1000 and a SMD

Hydrovision 1 MW prototype are scheduled forinstallation and testing at the European MarineEnergy Center in the Orkneys in late 2006 or 2007.

Although technologically ready for demonstration,many important questions about the application ofin- stream tidal energy to electricity generationremain to be answered, questions such as:

What type/size will yield optimal economics? Will the installed cost of tidal energy conversion

devices realize its potential of being lessexpensive than solar or wind?

Will the predictability of tidal earn a capacitycredit for its dispatch ability?

Will the performance, cost and reliabilityprojections be realized in practice once tidalenergy devices are deployed and operated?

We believe that this study makes a compelling casefor investing in tidal energy technology research,development and demonstration in the U.S. and

Canada starting with multiple demonstrationprojects as soon as possible.

Figure 14. MCT SeaGen geo technical testing atStrangford for foundation design and a blade mold

EPRI Recommendations

Collaboration

Encourage collaboration of State, Provincial andFederal Governments, Utilities, Power Producersand Non-Governmental Agencies, and Project andTidal Energy Device Developers.

Research and Development (R&D)

Encourage tidal energy technology R&D atuniversities and support graduate students desiringto earn advanced degrees with theses in tidalenergy. Areas of needed research include:

3D computational fluid dynamics coupled withaccurate velocity measurements for micro-sitingtidal plants, including pilot plants


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Understanding how turbulence, ice andsuspended sediment affect the choice oftechnology and its performance and lifetime

Understanding the energy extraction limit forprecluding significant ecological effects

Turbine interaction within an array to minimizespacing in limited seabed situations

Demonstration Test Projects

Encourage pilot scale demonstrations to show thetechnical and environmental feasibility of thetechnology and to reduce uncertainties inperformance, reliability, cost and servicingrequirements

Government Role

EPRI believes that the Government has a veryimportant role to play in the advancement of thistechnology to where it can be an option in our

energy supply portfolio; namely:

1. Providing leadership for the development of anocean energy RD&D program to fill known R&Dgaps identified in this report, and to acceleratetechnology development and prototype systemdeployment

2. Operating a national center to test theperformance and reliability of prototype oceanenergy systems under real conditions

3. Development of design and testing standards forocean energy devices

4. Leading activities to streamline the process for

licensing, leasing, and permitting renewableenergy facilities in U.S. and Canadian waters

5. Studying provision of production tax credits,renewable energy credits, and other incentivesto spur private investment in ocean energytechnologies and projects, and implementingappropriate incentives to accelerate oceanenergy deployment

6. Ensuring that the public receives a fair returnfrom the use of ocean energy resources

7. Ensuring that development rights are allocatedthrough a transparent process that takes intoaccount state, provincial, local, and public

concerns.8. Continue membership in the InternationalEnergy Agency (IEA) Ocean Energy Systems(OES) program.

EPRI Perspective

EPRI believes that a diversified and balancedportfolio of energy sources is the foundation of arobust and reliable electrical system and that in-stream tidal energy technology needs to be

evaluated for its role in contributing to our nationalportfolio of energy supply technologies.

The Electric Power Research Institute (EPRI) wasestablished in 1973 as an independent, nonprofitcenter for public interest energy and environmentalresearch. EPRI brings together memberorganizations, the Institutes scientists and

engineers, and other experts to work on solutionsto the challenges of electric power. For moreinformation, please contact:

Roger BedardEPRI (650) [email protected]

References: FINAL Reports are available atwww.epri.com/oceanenergy/

(1) EPRI TP-001-NA, Tidal In-stream Energy Resourceand Device Performance Estimation Methodology

(2) EPRI TP-002-NA, Tidal In-stream Energy ConversionEconomic Assessment Methodology(3) EPRI TP-003-MA, Massachusetts Site Survey(4) EPRI TP-003-ME, Maine Site Survey(5) EPRI TP-003-NB, New Brunswick Site Survey(6) EPRI TP-003-MA, Nova Scotia Site Survey(7) EPRI TP-004-NA, TISEC Device Survey and

Characterization(8) EPRI TP-005-NA, System Design Methodology(9) EPRI TP-006-AK, Alaska Pilot and Commercial

System Level Design Study(10) EPRI TP-006-WA, Washington Pilot and Commercial

System Level Design Study(11) EPRI TP-006-CA, California Pilot and Commercial

System Level Design Study

(12) EPRI TP-006-MA, Massachusetts Pilot andCommercial System Level Design Study

(13) EPRI TP-006-ME, Maine Pilot and Commercial SystemLevel Design Study

(14) EPRI TP-006-NB, New Brunswick Pilot andCommercial System Level Design Study

(15) EPRI TP-006-NS, Nova Scotia Pilot and CommercialSystem Level Design Study

(16) EPRI TP-007-NA, North America Environmental andRegulatory Issues Report

(17) EPRI Summer Seminar, 2005

Appendix - Frequently Asked Quest ions

What is tidal energy?

Tides are the result of gravitational forces exertedby the moon and the sun, with the moon having thepredominant influence. The changing relativepositions of these bodies cause the surface of theoceans to be raised and lowered periodically,creating two bulges, one closest to the moon andthe other on the opposite side of the globe. Thesebulges result in two tides a day, called semi-


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diurnal tides, the dominant pattern in the worldsoceans.

Will TISEC devices affect the environment?

Given proper care in site planning, in-stream tidalpower promises to be one of the moreenvironmentally benign electrical generation

technologies. We anticipate that these projects willrequire coordination with local, state and federalagencies and may include field studies. Baselineassessments can frequently be accomplishedthrough review of existing information anddatabases, in coordination with other proposedproject siting evaluations and through consultationwith appropriate resource agencies andstakeholders. During the environmental permittingprocess for each project, it is expected thatresource agency staff, other stakeholders, anddevelopers will discuss concerns regardingpotential project effects, project operation

characteristics, and how effects can be avoided orminimized.

In-stream tidal energy power plants are sized toextract only a small fraction of the energy availablein a tidal stream; that fraction is one that results inno noticeable effect to the ecology.

Will TISEC devices affect the fish?

While no definitive in-situ monitoring studies havebeen conducted to date, due to the newness of thetechnology and lack of deployed systems,

anecdotal information from numerous temporarytesting activities in the U.S., UK and abroad havenot observed any harm to aquatic life. Further,desk-top theoretical evaluations based ontechnology specifications (such as rotation speedand other physical parameters) and extensive fishstudies based on traditional hydro turbine systemssuggest these new technologies areenvironmentally friendly.

The blades of TISEC devices turn very slowly(around 10 rpm for a 18 meter diameter rotor) andthe speed at the tip of the blade is about 10-12 m/s(22-27 mph). The devices are self limiting in thatany faster speeds result in cavitation, a situationwhich cannot be allowed to exist by design.

Two TISEC test programs with thoroughenvironmental assessments of sea life and effectswill start in 2006; the Verdant RITE project in theEast River in NY and the MCT SeaGen project inStrangford UK.

Will these systems surv ive storms and hostilemarine environments?

Yes. Being totally submerged means that tidalenergy conversion systems will not need to bearthe full brunt of a storm. Relative to long-termsurvival in the environment, the anti-corrosion andbiofouling technology is such that oil and gas

platforms are surviving 50 years. The MCT 300 kWexperimental prototype, has been continuouslyoperating for almost 3 years (since May 2003) offthe coast of the UK with very little evidence ofbiofouling.

Will the regulatory authori ties grant a permit forin-stream tidal power plant?

The novelty of the technology will likely triggercautious environmental assessments and extensiveapproval processes. The difficulty of obtaining a

permit for an in-stream tidal power plant presents asignificant barrier to the development of TISECtechnology because:

There is a wide variety of regulations and largenumber of involved agencies

No specific fast-track regulations have beendeveloped for short-term marine renewabledemonstration projects which are small scale andgeared for research activities.

Permitting early tidal energy plants will be achallenge since there is no precedence in the USfor regulatory authorities to base a licensingdecision. Nevertheless, we believe that, with strongpublic support and the positive experiences in theUK and other countries, the Federal EnergyRegulatory Agency Commission (FERC) and otherfederal, state and local agencies will allow thisemerging technology power plant project to goforward.

Will TISEC technology provide reliable andcost-effective electricity?

Yes. TISEC technology in a good tidal site canprovide a cost of electricity in the same range as

existing commercial on-land wind technology,natural gas (at $5/mmBTU) and ultra supercriticalcoal and is a couple pennies less expensive thancoal with 85% CO2 capture and solar; and like windtechnology, emits no pollutants nor greenhousegases.

Tidal_Report_06-10-06.pdf

Documents

Transcript of Tidal_Report_06-10-06.pdf