INTEGRATION OF OFFSHORE WIND FARMS TO THE GREEK TRANSMISSION SYSTEM VIA

AN ISLAND INTERCONNECTION GRIDA. KoronidesA. KoronidesJ. KabourisJ. Kabouris

M. EfstathiouM. EfstathiouM. TsiliM. Tsili

Hellenic TSOHellenic TSOM. Papadopoulos M. Papadopoulos Em. Prof. of NTUAEm. Prof. of NTUA

President of the Hellenic TSOPresident of the Hellenic TSO

INTRODUCTION (1)

• Existing submarine cable Existing submarine cable interconnections:interconnections:

- - AC 150kV: All Ionian islands (1964 – 76)AC 150kV: All Ionian islands (1964 – 76)

- AC 15 – 20kV: About 65 islands (since 1960)- AC 15 – 20kV: About 65 islands (since 1960) - DC 500kV: Greece – Italy (2002)- DC 500kV: Greece – Italy (2002)

• Under construction: Under construction: Cycladic Interconnection Cycladic Interconnection

• Planned island interconnection of all Planned island interconnection of all the Aegean islands, in order to:the Aegean islands, in order to:

(a) Eliminate the existing oil powered stations(a) Eliminate the existing oil powered stations

(b) Exploit the excellent wind potential(b) Exploit the excellent wind potential

DEVELOPMENT STAGES

• ThreeThree main stages:main stages: (A) Preliminary planning of the “Aegean sea grid”, (A) Preliminary planning of the “Aegean sea grid”,

based on existing projectionsbased on existing projections (island loads and (island loads and proposals for RES installations)proposals for RES installations)

(B) Detailed design of the interconnection of each (B) Detailed design of the interconnection of each group of islands, to accommodate the RES plants group of islands, to accommodate the RES plants with installation licenseswith installation licenses

(C) Construction of each interconnection, when the (C) Construction of each interconnection, when the proper conditions proper conditions (economic feasibility, technical (economic feasibility, technical maturity etc)maturity etc) are obtained. are obtained.

ISLAND GROUPS and expected wind power

• Four main interconnections – island groupsFour main interconnections – island groups and expected wind capacity (on the islands):and expected wind capacity (on the islands):

(1) (1) Cycladic islands Cycladic islands (construction stage)(construction stage) Production licenses: Production licenses: 650MW650MW (2) North Aegean islands(2) North Aegean islands Production licenses: Production licenses: 700MW700MW (3) Crete (3) Crete Production licenses: Production licenses: 2.200MW2.200MW (4) Dodecanese (4) Dodecanese Expected wind power on the islands: Expected wind power on the islands: 700MW700MW

• Stand-alone interconnection – SkyrosStand-alone interconnection – Skyros with expected wind power 333MWwith expected wind power 333MW

Applications for offshore wind farms

GRID INTERCONNECTION

• EHV Substations (400/150 kV) have been EHV Substations (400/150 kV) have been chosen as connection points to the chosen as connection points to the mainland gridmainland grid– Robust system nodes (high short-circuit power)– Enough transmission capacity to absorb large

wind power capacity

• Limitations to the absorbed wind power Limitations to the absorbed wind power – Transmission system reinforcements for the

accommodation of wind power– Restrictions in the total installed wind capacity

due to the transfer capacity limits between North and South Greece

WIND POWER PENETRATION LIMITS

• of EHV Substations (400/150kV) of the mainland gridof EHV Substations (400/150kV) of the mainland grid

AEGEAN ISLANDS PROPOSED INTERCONNECTION SCHEME

• Accommodation of onshore wind farms Accommodation of onshore wind farms (4583MW)(4583MW)

AEGEAN ISLANDS PROPOSED INTERCONNECTION SCHEMES

Island GroupIsland Group Expected Wind Expected Wind Farms Installed Farms Installed Capacity (MW)Capacity (MW)

Connection PointConnection Point

(EHV Substation)(EHV Substation)

CycladesCyclades 650650 Pallini/LavrioPallini/Lavrio

North AegeanNorth Aegean 700700 Larymna/FilippoiLarymna/Filippoi

CreteCrete 22002200 Megalopoli/AharnesMegalopoli/Aharnes

DodecaneseDodecanese 700700 AharnesAharnes

SkyrosSkyros 333333 LarymnaLarymna

AEGEAN ISLANDS PROPOSED INTERCONNECTION SCHEMES

• Accommodation of offshore wind farmsAccommodation of offshore wind farms

Island GroupIsland Group Expected Expected Wind Farms Wind Farms Installed Installed Capacity Capacity (MW)(MW)

Connection PointConnection Point

(EHV Substation)(EHV Substation)

Fanari-ThasosFanari-Thasos 500500 FilippoiFilippoi

Alexandroupoli – Alexandroupoli – Samothraki – Samothraki – Limnos- Agios Limnos- Agios EfstratiosEfstratios

10001000 To be further investigated in To be further investigated in conjunction with possible onshore conjunction with possible onshore wind farm developments in wind farm developments in Thrace Thrace

KarpathosKarpathos 7070 DodecaneseDodecanese

KymiKymi 7575 AliveriAliveri

PetalioiPetalioi 180180 possibility of connection to possibility of connection to Aharnes or Pallini must be Aharnes or Pallini must be investigatedinvestigated

Kerkyra-LefkadaKerkyra-Lefkada 160160 Ahelwos/ArahthosAhelwos/Arahthos

Grid Interconnection Issues

• Connection of the Connection of the offshoreoffshore parks in islands parks in islands Alexandroupoli – Alexandroupoli – Samothraki – Limnos- Agios Efstratios must be further investigated Samothraki – Limnos- Agios Efstratios must be further investigated – – reductionreduction of the installed capacity of of the installed capacity of onshore parksonshore parks in the in the North Aegean islands or ThraceNorth Aegean islands or Thrace

• The possibility to accommodate the above offshore wind farms by The possibility to accommodate the above offshore wind farms by connection to connection to EHV substations (400/150 kV) of the South EHV substations (400/150 kV) of the South system is limitedsystem is limited due to the overall onshore installed capacities due to the overall onshore installed capacities in Cyclades/Dodecanesein Cyclades/Dodecanese

• The offshore wind farms in The offshore wind farms in KarpathosKarpathos can be accommodated by can be accommodated by the interconnection of the interconnection of DodecaneseDodecanese islands to the mainland grid islands to the mainland grid

• The connection of offshore wind farms in The connection of offshore wind farms in PetalioiPetalioi must be must be investigatedinvestigated due to the overall onshore installed capacities in due to the overall onshore installed capacities in Cyclades/Dodecanese that are connected to 400/150 kV of the Cyclades/Dodecanese that are connected to 400/150 kV of the South system (Aharnes/Pallini) South system (Aharnes/Pallini)

• No special considerations for the connection of offshore wind No special considerations for the connection of offshore wind farms in the rest of the considered islandsfarms in the rest of the considered islands

• There are possibilities of integration of offshore There are possibilities of integration of offshore wind farms to the greek transmission system via wind farms to the greek transmission system via an island interconnection grid in order to support an island interconnection grid in order to support Maritime Spatial Planning Maritime Spatial Planning

• The potential from offshore parks that can be The potential from offshore parks that can be accommodated by the existing or planned accommodated by the existing or planned submarine cable interconnections is highly submarine cable interconnections is highly dependent on the onshore wind farm dependent on the onshore wind farm developments (mainland/islands)developments (mainland/islands)

• Limitations to the absorbed wind power in the Limitations to the absorbed wind power in the mainland gridmainland grid imposed by the transmission imposed by the transmission system infrastructure should be consideredsystem infrastructure should be considered

Conclusions