NREL, Renewable Energy and Inter-island Power Transmission, 5-2011

7/31/2019 NREL, Renewable Energy and Inter-island Power Transmission, 5-2011

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Renewable Energy and Inter-island

Vahan Gevor ian

National Renewable Energy

Laboratory

CIEMADeS IV InternationalConference

Univ. of Turabo

,

May 06, 2011

NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

NREL/PR-5500-51819Composite photo created by NREL


2/34

NRELs Role in Variable Renewable Energy Integration

Integration studies and operational impacts;

Wind/solar lant modelin and interconnection

Transmission planning and analysis;

Resource assessment and forecasting.

Energy Development for Island Nations (EDIN)

U.S. Virgin Islands (reduce dependency on fossilfuel by 60% by 2025).

Iceland and Dominica collaboration. Pacific Islands.

NATIONAL RENEWABLE ENERGY LABORATORY 2

.


3/34

Overview

Submarine Power Transmission Technologies.

Hawaii Wind Integration and Transmission Study.

Caribbean Work.



4/34

HVAC vs. HVDC


+


5/34

HVDC Pros and Cons

A vantages Longdistancetransmissionwithlowercostsandlosses;

NohighcapacitanceeffectonDC(noreactivelosses);

Morepowerperconductor,noskineffect,2conductorsonly;

Connectingunsynchronizedgrids,rapidpowerflowcontrol;

,

Multiterminaloperation;

Goodfor

weaker

grids;

Helpsintegratinglargeamountofvariablegeneration.

Disadvantages

Highcostofpowerconverters;

Complexityofcontrol,communications,etc.;

MaintenancecosthigherthanforAC,sparepartsneeded;


HVDCcircuit

breaker

reliability

issue.


6/34

HVDC Technologies

HVDC Classic LCC Converters (bipole shown)

HVDC VSC Technology (bipole shown)



7/34

HVDC Configurations



8/34

Submarine Cables - How Deep?

Thecurrentexperienceislimitedtowaterdepthsupto1620m;

HVDCultra

deep

technology

up

to

2000

m

possible

no

experiencesofar;

Based

on

published

literature,

80

kVDC /

100

MW

is

possible

Additionaldevelopmentandtestingincludingfullscalesea

r a

snee e

or

g er

ep s.



9/34

Oahu Wind Integration and Transmission Study (OWITS)

awa ean nergy n a ve c o er Multi-year initiative;

70% clean energy by 2030 (40% by renewables);

A reement between state of Hawaii and HECO:

400 MW of wind from Lanai and/or Molokai to Oahu (Stage 1);

200 MW of wind from Maui to Oahu (Stage 2).

OWITSStudy

FY09/10;

TRCconsistsofregional,national,

andinternationalexperts;

e npersonmeet ngs;

Reviewedandprovidedfeedback

onstudymethods,dataneeds,and

results.



10/34

Big Wind Scenarios for HCEI (Stage 1)

Scenario

Oahu Lanai Molokai Oahu

.

2.OffislandWind 100 200

3.ConcentratedWind 100 400 100

5.HighRenewables 100 200 200 100

Stage2includes

interconnectiontoMaui.



11/34

OWITS Cable Study Inputs

Potentialcable

landing

points

and

interislandrouteshavebeenidentified

inOceanFloorSurveyReport(DBEDT);

Maximumwaterdepth around800

m;

Sendingandreceivingendvoltages

138kV;

PSSEloadflowdatafromHECO;

fortransmissionmodeling.



12/34

OWITS Option Screening Methodology

os s os s

ACCables DCCables

ACsubstations DCconverterstations

18 options analyzed (AC,DC, or combination of both).

Sea/landcabletransition Sea/landcabletransition

Fixedcompensation reactors

Othercom onents Othercom onentsStage 1

AClosses(20years) DClosses(20years)

TotalHVAC

cost Total

HVDC

cost

Only 6 selected for detailed

simulation (AC and DC).

Only 3 final scenarios (includinginterconnections to Maui) selected for RF


further detailed dynamic simulation.


13/34

All AC Option

Simulationswereconducted

138-kV

Bus

70-mile AC

under-sea

34.5-kV

Bus

600-V Bus

Spontaneous

breaker-open

Operation due

to over-voltage

protection

.

230kV/3corecable.

ACsolutionwillwork

230-kV

Bus

cable

200 MW of

Wind Turbines230-kV

Bus

withoutSVCorSTATCOM

enhancements(100%shunt

compensationisrequired).

Fibre-optic linkReceiving End Sending

End Depthsmayrepresent

challengesfor3coreAC

cables.



14/34

HVDC Option

HVDCOptionC32 HVDCOptionA32

HVDCOptionB32 HVDCOptionC12

HVDC O tion B12



15/34

Range for Budgetary Capital costs for HVDC options(including burial and termination)


, ,

www.nrel.gov/wind/systemsintegration/pdfs/2010/owits_summary_report.pdf)
http://www.nrel.gov/wind/systemsintegration/pdfs/2010/owits_summary_report.pdfhttp://www.nrel.gov/wind/systemsintegration/pdfs/2010/owits_summary_report.pdf


16/34

OWITS Final Scenario 1

400MW

bipole

VCS

link

betweenMolokaiand

Oahu.

ACcable

between

Molokai

andLanai.



17/34


200MWmonopoleVCS

linkbetweenMolokaiand

Oahu.

200MWmonopoleVCS

link

between

Molokai

and

Lanai.

ca e etween o o a ,

Lanai,andMaui.



18/34


400MWbipoleVCSlink

betweenMolokaiand

.

ACcable

between

Molokai,

Lanai,andMaui.



19/34

OWITS Cable Study Summary

ra eg es were eve ope o en ance n egra on o renewa es or eac

scenario: Wind power forecasting to improve commitment;

Refining the up-reserve requirements by using fast start units and load control;

Reducing minimum power of the baseload units;

Seasonally cycling off some selected baseload units\Increasing the thermal unit ramp-rate capability and enhancing the droop;

Considering advanced wind turbine technologies (inertia and frequency control);

Some aspects of short term storage were examined for implementing ramp rate limitsof wind plants.

Adequate reserve requirements for sustained drops in wind over an hour;

The largest drop in wind and solar power over 10-min. periods can be handledwith future improved AGC ramp rates;

Quick variations in wind and solar 1 to 5 min. time frame mi ht re uire short-term storage for up/down ramp rate limiting;

Detailed transient modeling to evaluate the systems response to worst casecontingences (voltage faults at different locations) was conducted;


PPAs were signed between HECO and Castle & Cook ($0.11 to 0.13/kWh plustransmission costs).


20/34

On-going Puerto Rico USVI: BVI Interconnection Study

DOEfundedproject

Participants

NREL

VIWAPA

PREPA/IAES

Siemens

Cableroutes

arenotional

Thestudyisfocusedonoptionsfor:

50mileinterconnectionbetweenPRandSTT;

NATIONAL RENEWABLE ENERGY LABORATORY

80+mile

interconnection

between

STT

and

STX;

or

DirectinterconnectionbetweenPRandSTXasanalternative.

20

PR USVI B h


21/34

PR-USVI Bathymetry


NRELdevelopedmap.Combinationof10,30,and100mhorizontalresolution,andbasedonNOAAdata.


22/34

Puerto Rico USVI Bathymetry

2200m2200m

1700m1700m


NRELdeveloped

map.

Combination

of

10,

30,

and

100

m

horizontal

resolution,

and

based

on

NOAA

data.


23/34

Puerto Rico USVI: BVI Interconnection Study Objectives

Determine

power

capacities,

types,

and

requirements

of

the

three

interconnections;

er ormpowersys ems u yan en ynecessary n ras ruc ure

reinforcements;

, , .

Estimateprojectcosts.

Project Timeline October 2010 Project kickoff

January 2010 Interim report #1 HVAC/HVDC requirement Submarine cable study

April 2011 Interim report #2

NATIONAL RENEWABLE ENERGY LABORATORY

Power system study

July 2011 Final report.

23

Example of AC and DCInterconnection option

NRELdevelopedmap.


24/34

Adding 30 MW of Wind (Extreme Scenario)

LOAD

70

80

STTLoadHourlyDataand30MWWind70

80

STTLoadHourlyDataand30MWWind

30

40

50

60

POWER(MW)

30

40

50

60

POWER(MW)

Baseload for combustion

0

10

20

0 24 48 72 96 120 144 168TIME(HR)

0

10

20

0 24 48 72 96 120 144 168TIME(HR)

generationreducedto20

MW;

60MWofvariableload;

o

ay

n g

pea s;

Bigchangeinpower

systemoperation.



25/34

How PREPA Interconnection Can Help?

STT

LOAD

PREPA

PREPAcan

provide

both

base

toWAPA.

Differentenergycoststructure

maybeassociatedwitheachservice.



26/34

PV Variability Will Contribute to Regulation Requirements

23.3MWPVinTrujillo,Extremadura, Spain(source:Suntech)

2.5MWPV,measuredinLasVegas,NVarea Singleaxistracking



27/34

Submarine Interconnection Can Help with Fast Regulation

HVDCInterconnectionExample

PREPA maintains large reserve capacity for Automatic

.

Faster (sub-second) power control is possible with HVDC option(built-in feature).


Voltage control simultaneous with power control.


28/34

Interconnection & Variable Generation Possible Contingencies

Shortself

recovering

Voltagedip

HVACInterconnectionExample

fault

Shortself

recovering

faults

will

create

voltage

dips

in

WAPA

system

(AC

link);

Maybeaseriousreliabilityissueduringtimesoflargepowerimports;

Windpowerlowvoltageridethrough(LVRT)capabilityisessentialforreliable

opera on;

OverallLVRTcapabilityofWAPAsystemcanbeimprovedbyFACTSincaseof

HVACinterconnection;


Modelingis

necessary

for

various

contingency

scenarios,

target

penetration

levels

andwindturbinetopologies,etc.


29/34

LargerRegionalInterconnection

USVIBenefits:

Diversifiedsupplyofenergy;

CleanbaseloadgeothermalpowerfromSt.Kitts/Nevis;

NRELdevelopedmap.

Cableroutesarenotional.

Higherreliability;

Lowerenergycosts.



30/34

Caribbean Power Interconnection and Renewable Energy

eenergyso u ons or e ar eanreg on nc u enew ue s e.g., ,

newenergy

resources,

and

electrical

interconnections

between

islands;

Geothermal owerisconsideredasamaindriverfortheinterconnection

Caribbean

wind

energy

(estimated

at

3.7

GW)

as

a

driver

for

interconnection?

Variabilityofwindpowerrepresentssignificantchallengescomparedto

baseloadgeothermalpower.



31/34

Caribbean Bathymetry

NRELdevelopedmap,1kmhorizontalresolution,basedonGEBCOdata.


Areas1,

2,

and

3 may

have

gaps

deeper

than

1650

m.


32/34

Caribbean Bathymetry and Slopes

andslopeslessthan200

NRELdevelopedmap,1kmhorizontalresolution,basedonGEBCOdata.



33/34

Potential Benefits of Regional Interconnections in Caribbean

Deliver

lower

cost

electrical

power

from

the

island

(or

country)

that

hassuchpowertoanisland(orcountry)thatdoesnot;

oss yo ransm ng argeamoun so e ec r ca energy

generatedby

renewable

sources;

, ,

sharedfrequencyregulationwithoutaddingnewgeneration;

Increasethe

potential

for

high

penetration

variable

renewable

generation;

Reducedependenceonhighpriceimportedoilandincreasehigh

levelutilization

of

renewable

energy

sources

on

the

regional

level;

Integratingfiberopticcommunicationcables.



34/34

Thank you !

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