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Submarine power cable

2025-05-19T20:44:13Z

2.202.3.217: /* Conductor */ grammar

{{Short description|Transoceanic electric power line placed on the seabed}}
[[File:Wolfe Island Wind Project Submarine Power Cable.jpg|thumb|Cross section of the submarine power cable used in [[Wolfe Island Wind Farm]].]]
[[File:HVDC_Europe.svg|thumb|HVDC connections around Europe Red=in operation Green=decided/under construction Blue=planned]]

A '''submarine power cable''' is a [[Power cable|transmission cable]] for carrying [[electric power]] below the surface of the water.<ref name=nyt20100316>
[https://www.nytimes.com/2010/03/17/business/energy-environment/17power.html Underwater Cable an Alternative to Electrical Towers], Matthew L. Wald, ''[[New York Times]]'', 2010-03-16, accessed 2010-03-18.</ref> These are called "submarine" because they usually carry electric power beneath [[Seawater|salt water]] (arms of the [[ocean]], [[sea]]s, [[strait]]s, etc.) but it is also possible to use submarine power cables beneath [[fresh water]] (large [[lake]]s and [[river]]s). Examples of the latter exist that connect the mainland with large islands in the [[St. Lawrence River]].

==Design technologies==
{{More citations needed section|date=May 2022}}
As key tools in [[bulk power transmission]], submarine power tables tend to operate at high voltage{{Cn|date=May 2025}} in order to minimize [[resistive losses]] between the endpoints.<ref> https://www.google.com/books/edition/Electric_Power_Transmission_and_Distribu/KpY1hpKKwdQC?hl=en&gbpv=1&bsq=high%20voltage%20power%20transmission page 436: "The possibility for a reduction in current for an increase in voltage has an important economic aspect of power transmission. In the case of a transmission system the load, which the conductors can carry, will depend on the heating effects of the current. Hence, of the current can be reduced by using a high voltage, the resistance can be increased without incurring additional losses and causing a greater temperature rise. Therefore, we can use smaller conductors, thus, saving cost. Alternatively, with the same conductor the losses and voltage drops are reduced and the efficiency of transmission is increased."</ref> Unlike [[overhead powerline]]s, many submarine power cables tend to operate with DC current. [[Electrical phase]]s must endure [[proximity effect (electromagnetism)|close proximity]] inside the cable, increasing [[parasitic capacitance]]. It is more economical to use AC only with lines shorter than 100 km in length, in which case losses at the [[cable landing point|landing point]] grid interfaces dominate.<ref name=":1">Ardelean, M.; Minnebo, P. The suitability of seas and shores for building submarine power interconnections. Renewable Sustainable Energy Rev 2023, 176, 10.1016/j.rser.2023.113210.</ref>

When the reasons for high voltage transmission, the preference for AC, and for capacitive currents are combined, one can understand why there are no underwater high electric power cables longer than 1000 km (see the table in "Operational submarine power cables" section below).

===Conductor===
As indicated above, submarine power cables transport [[electric current]] at [[high voltage]]. The electric core is a concentric assembly of inner [[Electrical conductor|conductor]], [[Insulator (electricity)|electric insulation]], and protective layers (resembling the design of a [[coaxial cable]]).<ref>"Submarine Power Cables - Design, Installation, Repair, Environmental aspects", by T Worzyk, Springer, Berlin Heidelberg 2009</ref> Modern three-core cables (e.g. for the connection of [[Offshore wind power|offshore wind turbines]]) often carry [[optical fiber]]s for data transmission or temperature measurement, in addition to the electrical conductors.
The [[Electrical conductor|conductor]] is made from [[Copper conductor|copper]] or aluminum wires, the latter material having a small but increasing market share. Conductor sizes ≤ 1200 mm2 are most common, but sizes ≥ 2400 mm2 have been made occasionally. For voltages ≥ 12 kV the conductors are round so that the insulation is exposed to a uniform [[electric field gradient]]. The conductor can be stranded from individual round wires or can be a single solid wire. In some designs, profiled wires (keystone wires) are laid up to form a round conductor with very small interstices between the wires.

===Insulation===
Three different types of [[Insulator (electricity)|electric insulation]] around the conductor are mainly used today.
[[Cross-linked polyethylene]] (XLPE) is used up to 420 kV system voltage. It is produced by [[extrusion]], with an insulation thickness of up to about 30 mm; 36 kV class cables have only 5.5 – 8 mm insulation thickness. Certain formulations of XLPE insulation can also be used for DC.
Low-pressure oil-filled cables have an insulation lapped from paper strips. The entire cable core is impregnated with a low-[[viscosity]] insulation fluid ([[mineral oil]] or synthetic). A central oil channel in the conductor facilitates oil flow in cables up to 525 kV for when the cable gets warm but rarely used in submarine cables due to [[oil pollution]] risk with cable damage.
Mass-impregnated cables have also a paper-lapped insulation but the impregnation compound is highly viscous and does not exit when the cable is damaged. Mass-impregnated insulation can be used for massive [[HVDC]] cables up to 525 kV.

===Armoring===
Cables ≥ 52 kV are equipped with an extruded lead sheath to prevent water intrusion. No other materials have been accepted so far. The lead alloy is extruded onto the insulation in long lengths (over 50 km is possible).
In this stage the product is called cable core. In single-core cables the core is surrounded by concentric armoring. In three-core cables, three cable cores are laid-up in a spiral configuration before the armoring is applied.
The armoring consists most often of steel wires, soaked in bitumen for corrosion protection. Since the alternating magnetic field in AC cables causes losses in the armoring, those cables are sometimes equipped with non-magnetic metallic materials (stainless steel, copper, brass).

==Operational submarine power cables==

===Alternating current cables===
[[Alternating current|Alternating-current]] (AC) submarine cable systems for transmitting lower amounts of [[three-phase electric power]] can be constructed with three-core cables in which all three insulated conductors are placed into a single underwater cable. Most offshore-to-shore wind-farm cables are constructed this way.

For larger amounts of transmitted power, the AC systems are composed of three separate single-core underwater cables, each containing just one insulated conductor and carrying one phase of the three phase electric current. A fourth identical cable is often added in parallel with the other three, simply as a spare in case one of the three primary cables is damaged and needs to be replaced. This damage can happen, for example, from a ship's [[anchor]] carelessly dropped onto it. The fourth cable can substitute for any one of the other three, given the proper [[electrical switch]]ing system.

{| class="wikitable sortable"
!Connecting!!Connecting!!Voltage ([[kilovolt|kV]])!!Length(km)!!Year!!Notes
|-
| [[Peloponnese]], [[Greece]] || [[Crete]], [[Greece]] || 150 || 135 || 2021 || Two 3-core XLPE cables with total capacity of 2x200MVA. 174 km total length including the underground segments. Maximum depth 1000m. Total cost 380 million EUR. It is the longest submarine/underground AC cable interconnection in the world.<ref>{{Cite web|url=http://www.admie.gr/en/nea/deltia-typoy/crete-peloponnese-record-breaking-interconnection-completed|title=Crete-Peloponnese: The record-breaking interconnection is completed|website=IPTO}}</ref><ref>{{Cite web|url=http://admieholding.gr/crete-peloponnese-interconnection-selection-of-tenderers-for-the-cables-of-one-of-the-most-important-submarine-interconnection-projects-globally/?lang=en|title=Crete – Peloponnese Interconnection. Selection of tenderers for the cables of one of the most important submarine interconnection projects globally|website=admieholding.gr|access-date=2020-03-05|archive-date=2020-10-18|archive-url=https://web.archive.org/web/20201018221426/http://admieholding.gr/crete-peloponnese-interconnection-selection-of-tenderers-for-the-cables-of-one-of-the-most-important-submarine-interconnection-projects-globally/?lang=en|url-status=dead}}</ref><ref>{{Cite web|url=https://www.researchgate.net/publication/330663865|title=Crete – Peloponnese 150kV AC Interconnection.|website=www.researchgate.net}}</ref>
|-
|[[British Columbia|Mainland British Columbia]] to [[Gulf Island]]s [[Galiano Island]], Parker Island, and [[Saltspring Island]] thence to [[North Cowichan]] ||[[Vancouver Island]] || 138 || 33 || 1956 ||"The cable became operational on 25 September 1956" <ref>{{Cite web|url=https://search-bcarchives.royalbcmuseum.bc.ca/132-000-volt-submarine-cable-in-mainland-vancouver-island-interconnection-part-3-cable-laying|title=The 132,000 volt submarine cable in the Mainland - Vancouver Island interconnection : part 3, cable laying - RBCM Archives|website=search-bcarchives.royalbcmuseum.bc.ca}}</ref>
|-
|[[British Columbia|Mainland British Columbia]] to [[Texada Island]] to Nile Creek Terminal||[[Vancouver Island]] / Dunsmuir Substation ||525|| 35 ||1985 || Twelve, separate, oil filled single-phase cables. Nominal rating 1200 MW.<ref>{{cite web|url=https://www.bcuc.com/Documents/Proceedings/2005/DOC_7818_B1-1%20(Part%201%20of%202)%20VITR%20CPCN%20Application%20and%20Appx%20A-D.pdf|archive-url=https://web.archive.org/web/20210526212756/https://www.bcuc.com/Documents/Proceedings/2005/DOC_7818_B1-1%20(Part%201%20of%202)%20VITR%20CPCN%20Application%20and%20Appx%20A-D.pdf|url-status=live|title=British Columbia Transmission Corporation Application for Certificate of Public Convenience and Necessity For Vancouver Island Transmission Reinforcement Project|archive-date=2021-05-26}}</ref>
|-
|[[Tarifa]], [[Spain]] ([[Spain-Morocco interconnection]])||Fardioua, [[Morocco]] through the [[Strait of Gibraltar]]||400||26||1998|| A second one from 2006<ref>[http://tdworld.com/underground-tampd/bridge-between-two-continents "A Bridge Between Two Continents"], Ramón Granadino and Fatima Mansouri, ''Transmission & Distribution World'', May 1, 2007. Consulted March 28, 2014.</ref> Maximum depth: {{convert|660|m|ft|abbr=on}}.<ref>"Energy Infrastructures in the Mediterranean: Fine Accomplishments but No Global Vision", Abdelnour Keramane, [http://www.iemed.org/publicacions-en/historic-de-publicacions/anuari-de-la-mediterrania IEMed Yearbook] {{Webarchive|url=https://web.archive.org/web/20201020193136/https://www.iemed.org/publicacions-en/historic-de-publicacions/anuari-de-la-mediterrania |date=2020-10-20 }} 2014 ([http://www.iemed.org/?set_language=en European Institute of the Mediterranean]), under publication. Consulted 28 March 2014.</ref>
|-
|[[Norwalk, Connecticut|Norwalk, CT]], USA
|[[Northport, New York|Northport, NY]], USA
|138|| 18 ||
|A 3 core, XLPE insulated cable
|-
|[[Sicily]]||[[Malta]]||220 ||95|| 2015 ||The [[Malta–Sicily interconnector]]
|-
|[[Sweden|Mainland Sweden]]||[[Bornholm|Bornholm Island, Denmark]]||60|| 43.5|| ||The [[Bornholm Cable]]
|-
|[[Italy|Mainland Italy]]||[[Sicily]]||380||38||1985|| [[Pylons of Messina#Messina Strait submarine cable|Messina Strait submarine cable]] replacing the "[[Pylons of Messina]]". A second 380 kV cable began operation in 2016
|-
|[[Germany]]||[[Heligoland]]||30|| 53|| ||<ref>{{cite web|title=Mit der Zukunft Geschichte schreiben|url=http://www.kreiszeitung-wesermarsch.de/Home/region/nordenham_Mit-der-Zukunft-Geschichte-schreiben-_arid,159098_regid,1.html|url-status=dead|archive-url=https://web.archive.org/web/20110719053515/http://www.kreiszeitung-wesermarsch.de/Home/region/nordenham_Mit-der-Zukunft-Geschichte-schreiben-_arid%2C159098_regid%2C1.html|archive-date=19 July 2011|work=Dithmarscher Kreiszeitung|language=de}}</ref>
|-
|[[Negros Island]]||[[Panay Island]], the Philippines||138|| || ||
|-
|[[Douglas Head]], Isle of Man,||[[Bispham, Blackpool]], England||90||104 ||1999||The [[Isle of Man to England Interconnector]], a 3 core cable
|-
|[[Wolfe Island (Ontario)|Wolfe Island, Canada]] for the [[Wolfe Island Wind Farm]]||[[Kingston, Ontario|Kingston, Canada]]||245|| 7.8|| 2008||The first three-core [[Cross-linked polyethylene|XLPE]] submarine cable for 245 kV<ref>{{cite journal|title=Wolfe Island Wind Project|journal=Canadian Copper CCBDA|year=2008|issue=156|url=http://www.coppercanada.ca/pdfs/CCMagazinePDFs/E156a.pdf|access-date=3 September 2013}}</ref>
|-
|[[Cape Tormentine, New Brunswick]]||[[Borden-Carleton]], [[Prince Edward Island|PEI]]||138||17|| 2017||[[Prince Edward Island Cables]]<ref name="cbc_170829">{{cite news |title=P.E.I.'s underwater electric cable project officially plugged in - New underwater cables supply about 75% of the Island's electricity |url=https://www.cbc.ca/news/canada/prince-edward-island/pei-electric-underwater-cable-northumberland-strait-1.4267315 |access-date=1 August 2020 |agency=CBC News |date=Aug 29, 2017}}</ref>
|-
|[[Taman Peninsula|Taman Peninsula, Mainland Russia]]||[[Kerch Peninsula]], [[Crimea]]||220||57|| 2015||<ref>[[:ru:Энергомост в Крым|The corresponding page on Russian Wikipedia]] cites [https://minek.rk.gov.ru/file/File/2015/06-June/16/fcp_new.pdf the June 15, 2015 changes] (in Russian) to Russian federal program "Socio-economic development of the Republic of Crimea and the city of Sevastopol until 2020 [Социально-экономическое развитие Республики Крыми г. Севастополя до 2020 года]". </ref>
|}

===Direct current cables===
{{see also|List of HVDC projects}}
{| class="wikitable sortable"
!Name!!Connecting!!Body of water!!Connecting!![[kilovolt]]s (kV)!!Undersea distance
!Year!!Notes
|-
|[[Baltic Cable]]||[[Germany]]||[[Baltic Sea]]||[[Sweden]]||450 ||{{convert|250|km|mi|abbr=on}}
|1994||
|-
|[[Basslink]]||mainland [[State of Victoria]]||[[Bass Strait]]||[[Tasmania|island State of Tasmania]], [[Australia]]||500||{{convert|290|km|mi|abbr=on}}<ref>{{cite web|url=http://www.basslink.com.au/basslink-interconnector/about/|title=Basslink - About|access-date=11 February 2018|work=www.basslink.com.au}}</ref>
|2005||
|-
|[[BritNed]]||[[Netherlands]]||[[North Sea]]||[[Great Britain]]||450||{{convert|260|km|mi|abbr=on}}
|2010||
|-
|[[COBRAcable]]||[[Netherlands]]||[[North Sea]]||[[Denmark]]||320||{{convert|325|km|mi|abbr=on}}
|2019||
|-
|[[Cross Sound Cable]]||[[Long Island, New York]]||[[Long Island Sound]]||[[State of Connecticut]]||150 ||
|2003||{{citation needed|date=December 2010}}
|-
|[[East–West Interconnector]]||Dublin, [[Ireland]]||[[Irish Sea]]||North [[Wales]] and thus the British grid||200 ||{{convert|186|km|mi|abbr=on}}
|2012||
|-
|[[Estlink]]||northern [[Estonia]]||[[Gulf of Finland]]||southern [[Finland]]|| 330 ||{{convert|105|km|mi|abbr=on}}
|2006||
|-
|[[Fenno-Skan]]||Sweden||Baltic Sea||Finland||400 ||{{convert|233|km|mi|abbr=on}}
|1989||
|-
|[[HVDC Cross-Channel]]||[[France|French mainland]]||[[English Channel]]||[[Great Britain|England]]||270 ||{{convert|73|km|mi|abbr=on}}
|1986 || very high power cable (2000 MW){{citation needed|date=November 2014}}
|-
|[[HVDC Gotland]]||[[Sweden|Swedish mainland]]||Baltic Sea||Swedish island of [[Gotland]]||150 ||{{convert|98|km|mi|abbr=on}}
|1954|| 1954, the first HVDC submarine power cable (non-experimental)<ref>{{cite web |url=https://www.escaeu.org/articles/submarine-power-cables/ |title=European Subsea Cables Association - Submarine Power Cables |work=www.escaeu.org}}</ref> Gotland 2 and 3 installed in 1983 and 1987.
|-
|[[HVDC Inter-Island]]||[[South Island]]||[[Cook Strait]]||[[North Island]]|| 350||{{convert|40|km|mi|abbr=on}}
|1965|| between the power-rich South Island (much [[hydroelectric power]]) of [[New Zealand]] and the more-populous North Island.
|-
|[[HVDC Italy-Corsica-Sardinia]] (SACOI)||Italian mainland||[[Mediterranean Sea]]||the Italian island of [[Sardinia]], and its neighboring French island of [[Corsica]]||200 ||{{convert|385|km|mi|abbr=on}}
|1967|| 3 cables, 1967, 1988, 1992<ref>{{cite web |title=Sardinia's electricity transmission network |url=https://www.ingdemurtas.it/en/energy/sardinia-el-network/ |date=2009}}</ref>
|-
|[[HVDC Italy-Greece]]||Italian mainland - Galatina HVDC Static Inverter||[[Adriatic Sea]]||[[Greece|Greek mainland]] - Arachthos HVDC Static Inverter||400||{{convert|160|km|mi|abbr=on}}
|2001|| Total length of the line is 313 km (194 mi)
|-
|[[HVDC Leyte - Luzon]]||[[Leyte Island]]||[[Pacific Ocean]]||[[Luzon]] in the [[Philippines]]{{citation needed|date=December 2010}}|| ||
|1998||
|-
|[[HVDC Moyle]]||[[Scotland]]||[[Irish Sea]]||[[Northern Ireland]] within the [[United Kingdom]], and thence to the [[Republic of Ireland]]||250 || {{convert|63.5|km|abbr=on}}
|2001|| 500MW
|-
|[[HVDC Vancouver Island]]||[[Vancouver Island]]||[[Strait of Georgia]]||[[British Columbia|mainland of the Province of British Columbia]]||280 ||33 km
|1968 || In operation in 1968 and was extended in 1977
|-
|[[Kii Channel HVDC system]]||[[Honshu]]||[[Kii Channel]]||[[Shikoku]]||250 ||{{convert|50|km|abbr=on}}
|2000 || in 2010 the world's highest-capacity{{citation needed|date=November 2014}} long-distance submarine power cable{{inconsistent}} (rated at 1400 [[megawatt]]s). This power cable connects two large islands in the [[Japanese Home Islands]]
|-
|[[Kontek]]||Germany||Baltic Sea||Denmark|| ||
|1995||
|-
|[[Konti-Skan]]<ref>{{cite web |url=http://www.transmission.bpa.gov/cigresc14/Compendium/KONTI.htm |title=THE KONTI-SKAN HVDC SCHEME |work=www.transmission.bpa.gov |archive-url=https://web.archive.org/web/20050902175957/http://www.transmission.bpa.gov/cigresc14/Compendium/KONTI.htm |archive-date=2005-09-02 }}</ref>||Sweden||[[Kattegat]]||[[Denmark]]||400 ||{{convert|149|km|abbr=on}}
|1965||Commissioned:1965 (Kontiskan 1);1988 (Kontiskan 2)

Decommissioned:2006 (Kontiskan 1)
|-
|[[Lower Churchill Project#Maritime Link|Maritime Link]]||[[Newfoundland]]||[[Atlantic Ocean]]||[[Nova Scotia]]||200 ||{{convert|170|km|abbr=on}}
|2017|| 500 MW link went online in 2017 with two subsea HVdc cables spanning the [[Cabot Strait]].<ref>{{Cite web|url=https://www.emeranl.com/maritime-link/maritime-link-infrastructure|title=Maritime Link Infrastructure|website=Emera Newfoundland and Labrador}}</ref>
|-
|[[Nemo Link|Nemo-Link]]<ref>{{Cite news|url=https://www.reuters.com/article/uk-britain-power-idUKKCN1P81IJ|title=New UK-Belgium power link to start operating on Jan. 31|first= Nina |last= Chestney |date=January 14, 2019| newspaper=Reuters }}</ref>||[[Belgium]]||North Sea||United Kingdom||400 ||{{convert|140|km|abbr=on}}
|2019||
|-
|[[Neptune Cable]]||[[State of New Jersey]]||[[Atlantic Ocean]]||[[Long Island, New York]]||500||{{convert|104.6|km|abbr=on}}<ref>{{Cite web|url=https://neptunerts.com/|title=Home|website=Neptune Regional Transmission System}}</ref>
|2003||
|-
|[[NordBalt]]||Sweden||Baltic Sea||[[Lithuania]]||300||{{convert|400|km|mi|abbr=on}}
|2015||Operations started on February 1, 2016 with an initial power transmission at 30 MW.<ref>{{cite web|url= http://www.litgrid.eu/index.php/news-events-/news/power-successfully-transmitted-through-nordbalt-cable/3086 |title= Power successfully transmitted through NordBalt cable |website= [[Litgrid|litgrid.eu]] |date= 2016-02-01 |access-date= 2016-02-02}}</ref>
|-
|[[NordLink]]|| Ertsmyra, Norway||North Sea||[[Büsum]], Germany||500||{{convert|623|km|abbr=on}}
|2021||Operational May 2021<ref name=opening>{{Cite web|title=NordLink - TenneT|url=https://www.tennet.eu/our-grid/international-connections/nordlink/ |access-date=2021-10-17|website=www.tennet.eu}}</ref>
|-
|[[NorNed]]||[[Eemshaven]], Netherlands|| ||[[Feda, Norway]]||450||{{convert|580|km|abbr=on}}
|2012|| 700 MW in 2012 previously the longest undersea power cable<ref>{{Cite web|url=http://www05.abb.com/global/scot/scot221.nsf/veritydisplay/f3a6c2afe601d185c125718e002e3823/$File/THE%20NORNED%20HVDC%20CABLE%20LINK.pdf|title=The Norned HVDC Cable Link |work=www05.abb.com}}</ref>
|-
|[[North Sea Link]]|| [[Ulla-Førre#Kvilldal Hydroelectric Power Station|Kvilldal]], [[Suldal]], in Norway, [[Cambois]] near [[Blyth, Northumberland|Blyth]]|| North Sea ||United Kingdom, Norway||515||{{convert|720|km|abbr=on}}
|2021|| 1.4 GW the longest undersea power cable
|-
|[[Shetland HVDC Connection]]||Shetland islands||North Sea||Scotland||600 ||{{convert|260|km|abbr=on}}
|2024||
|-
|[[Skagerrak (power transmission system)|Skagerrak 1-4]]||Norway||[[Skagerrak]]||Denmark (Jutland)||500 ||{{convert|240|km|abbr=on}}
|1977|| 4 cables - 1700 MW in all<ref>{{Cite web |url=http://new.abb.com/systems/hvdc/references/skagerrak |title=Skagerrak An excellent example of the benefits that can be achieved through interconnections. |work=new.abb.com |access-date=2016-01-21 |archive-date=2016-01-20 |archive-url=https://web.archive.org/web/20160120170439/http://new.abb.com/systems/hvdc/references/skagerrak |url-status=dead }}</ref>
|-
|[[SwePol]]||[[Poland]]||Baltic Sea||Sweden|| 450 ||
|2000||
|-
|[[Western HVDC Link]]||[[Scotland]]||Irish Sea||Wales|| 600 || {{convert|422|km|abbr=on}}
|2019|| Longest 2200 MW cable, first 600kV undersea cable<ref>{{Cite web|url=http://www.westernhvdclink.co.uk/marine-cable.aspx|title=None |work=www.westernhvdclink.co.uk}}</ref>
|}

==Submarine power cables under construction==
* 500 MW capacity, 165 km DC [[Lower Churchill Project|Maritime Transmission Link]] between the Canadian province of [[Newfoundland and Labrador]] and the province of [[Nova Scotia]].<ref>{{cite web | url=http://www.nalcorenergy.com/Lower-Churchill-Project.asp | publisher=Nalcor Energy | title=Lower Churchill Project | access-date=2013-06-08 | archive-date=2016-11-29 | archive-url=https://web.archive.org/web/20161129063257/http://www.nalcorenergy.com/Lower-Churchill-Project.asp | url-status=dead }}</ref>
* British and [[Denmark|Danish]] power companies ([[National Grid (Great Britain)|National Grid]] and [[Energinet.dk]], respectively) are building [[Viking Link]], a 740 km cable to provide the two countries with 1,400 MW transmission by 2022.<ref>{{Cite web|title = Kabel til England - Viking Link|url = http://energinet.dk/DA/ANLAEG-OG-PROJEKTER/Anlaegsprojekter-el/Kabel-til-England-Viking-Link/Sider/default.aspx|website = energinet.dk|access-date = 2015-11-12|archive-date = 2017-03-23|archive-url = https://web.archive.org/web/20170323121607/http://www.energinet.dk/DA/ANLAEG-OG-PROJEKTER/Anlaegsprojekter-el/Kabel-til-England-Viking-Link/Sider/default.aspx|url-status = dead}}</ref><ref>{{cite web |url= http://www2.nationalgrid.com/About-us/European-business-development/Interconnectors/denmark/ |title= Denmark - National Grid |website= [[National Grid (Great Britain)|nationalgrid.com]] |access-date= 2016-02-03 |url-status= dead |archive-url= https://web.archive.org/web/20160303152334/http://www2.nationalgrid.com/About-us/European-business-development/Interconnectors/denmark/ |archive-date= 2016-03-03 }}</ref>
*Black Sea submarine electric cable with a capacity of 1 GW and voltage of 500 kV will transfer green electricity from Azerbaijan through Georgia, Romania, Moldova to the EU. It is estimated to be approximately 1100 km in length and to be built in late 2029.<ref>{{Cite web|title = Quadrilateral agreement inked on Black Sea electric cable Link|url = https://english.news.cn/20221217/80224854014b4bcc8eeae745be840556/c.html|url-status = dead|access-date = 2022-12-17|archive-date = 2022-12-17|archive-url = https://web.archive.org/web/20221217180428/https://english.news.cn/20221217/80224854014b4bcc8eeae745be840556/c.html}}</ref>

==Proposed submarine power cables==
{{update section|date=April 2020}}
* [[Australia–ASEAN Power Link]] (AAPL), or the Australia–Singapore Power Link (ASPL), is a proposed electricity infrastructure project that is planned to include the world's longest submarine power cable. A solar farm in Northern Territory, Australia, will produce 10 gigawatts of electricity, most of which will be exported to Singapore by a 4,500 km (2,800 mi) 3 GW HVDC transmission line.<ref name=":0">{{Cite news|date=2020-07-30|title=Australia Fast Tracks Approval Process for $16 Billion Solar Power Export Project|language=en-US|work=Reuters|url=https://www.reuters.com/article/us-australia-renewables-idUSKCN24V0S7|access-date=2020-11-03|issn=0362-4331}}</ref>
* [[EuroAsia Interconnector]], a 1,520 km submarine power cable, reaching depths of up to {{convert|3|km|mi|abbr=on}} under sea level, with the capacity to transmit 2,000 megawatts of electricity connecting Asia and Europe (Israel–Cyprus–Greece)<ref name="EA">[http://www.euroasia-interconnector.com/wp-content/uploads/2018/01/EuroAsia_Interconnector_Project_and_Progress_English.pdf The EuroAsia Interconnector document], ''www.euroasia-interconnector.com'' October 2017.</ref><ref name=mirror35471>
{{cite news
| title = ENERGY: End to electricity isolation a step closer
| newspaper = [[Financial Mirror]]
| date = 2017-10-19
| url = http://www.financialmirror.com/news-details.php?nid=35471
| access-date = 2017-01-04}}
</ref><ref>{{cite news| url=https://af.reuters.com/article/energyOilNews/idAFL5E8CN25B20120123 | archive-url=https://web.archive.org/web/20120126080043/http://af.reuters.com/article/energyOilNews/idAFL5E8CN25B20120123 | url-status=dead | archive-date=2012-01-26 | work=Reuters | title=Cyprus group plans Greece-Israel electricity link | date=2012-01-23}}</ref>
* [[Champlain Hudson Power Express]], 335-mile line. The Transmission Developers Company of [[Toronto|Toronto, Ontario]], is proposing "to use the [[Hudson River]] for the most ambitious underwater transmission project yet. Beginning south of [[Montreal]], a 335-mile line would run along the bottom of [[Lake Champlain]], and then down the bed of the [[Hudson River|Hudson]] all the way to [[New York City]]."<ref name="FERC_Application">{{citation|title=Application for Authority to Sell Transmission Rights at Negotiated Rates and Request for Expedited Action |author=Transmission Developers Inc. |publisher=Federal Energy Regulatory Commission|date=2010-05-03 |page=7|url=http://elibrary.ferc.gov/idmws/common/opennat.asp?fileID=12337760 | access-date = 2010-08-02 }}</ref>
* Power Bridge, [[Hawaii]]<ref name=nyt20100316/>
* Power Bridge, [[State of Maine]]<ref name=nyt20100316/>
* [[Puerto Rico]] to the [[Virgin Islands]]<ref>{{Cite web|url=https://stcroixsource.com/2010/06/29/territory-study-linking-power-grid-puerto-rico/|archiveurl=https://web.archive.org/web/20110716134527/http://stcroixsource.com/content/news/local-news/2010/06/29/territory-study-linking-power-grid-puerto-rico|url-status=dead|title=Territory to Study Linking Power Grid to Puerto Rico |work=stcroixsource.com |date=June 29, 2010|archivedate=July 16, 2011}}</ref>
* 400 kV HVDC [[India]] to [[Sri Lanka]]<ref>[http://www.geni.org/globalenergy/library/technical-articles/transmission/eesoc.org/hvdc-transmission-and-india-sri-lanka-power-link/index.shtml ''HVDC Transmission & India-Sri Lanka Power Link'' www.geni.org 2010]</ref>
* 220 kV HVAC, 225 megawatts, 117 km [[Malta–Sicily interconnector]] between Magħtab, Malta, and [[Ragusa, Sicily]].<ref>{{Cite web|url=https://timesofmalta.com/articles/view/malta-signs-182-million-interconnector-contract.340985|title=Malta signs €182 million interconnector contract|website=Times of Malta|date=15 December 2010 }}</ref>
* The 3,500-km, 6-GW North Atlantic Transmission One Link between Newfoundland and Ireland was proposed in 2024 by three investment bankers to ensure secure coordination between the North American and Western European power grids.<ref name="Čavčič 2024">{{cite web | last=Čavčić | first=Melisa | title=World's 'most ambitious' subsea interconnector igniting zest for clean power superhubs: Embracing NATO-L to reinforce energy security bonds between America and Europe | website=Offshore Energy | date=July 31, 2024 | url=https://www.offshore-energy.biz/worlds-most-ambitious-subsea-interconnector-igniting-zest-for-clean-power-superhubs-embracing-nato-l-to-reinforce-energy-security-bonds-between-america-and-europe/ | access-date=October 28, 2024}}</ref>
* The 58.9-km, 161-kV [[Taiwan]] Island to the [[Penghu|Penghu Islands]] submarine power cable system (T–P-cable), the first submarine project of the [[Taiwan Power Company]] (Taipower) at this level, scheduled for completion in 2014. On 24 December 2010, the ''[[Taiwan-Penghu Undersea Cable]] Project'' of [[Taipower]] was approved to connect the [[electrical grid]] in Taiwan Island to the Penghu Islands.<ref>{{cite web|url=http://www.taipower.com.tw/e_content/content/events/events01-1.aspx?sid=2|title=Taiwan power company-Taipower Events |work=www.taipower.com.tw |url-status=dead|archive-url=https://web.archive.org/web/20140517160458/http://www.taipower.com.tw/e_content/content/events/events01-1.aspx?sid=2|archive-date=2014-05-17}}</ref>
* The British and Icelandic Governments are supposedly in "active discussion" to build a cable ([[Icelink]]) between [[Scotland]] and [[Iceland]] to carry [[geothermal power]] to Scotland. It would be 1,000 to 1,500 km long "and by far the longest in the world."<ref>{{cite news| url=https://www.theguardian.com/environment/2012/apr/11/iceland-volcano-green-power | location=London | work=The Guardian | first=Damian | last=Carrington | title=Iceland's volcanoes may power UK | date=2012-04-11}}</ref> assuming a longer cable not yet built like the proposed 4,200 km Australia–Singapore cable
* FAB between [[Great Britain]] and [[France]] via [[Alderney|Alderney Island]] in the [[Channel Islands]].<ref>[http://www.fablink.net/ FAB] website fablink.net, as well as (fr) [http://www.rte-france.com/fr/projet/interconnexion-france-aurigny-grande-bretagne-fab Interconnexion France Aurigny Grand-Bretagne] website rte-france.com, site of ''[[Réseau de Transport d'Électricité]]''.</ref>
* [[EuroAfrica Interconnector]], a 1,707 km submarine power cable, reaching depths of up to {{convert|3|km|mi|abbr=on}} under sea level, with the capacity to transmit 2,000 megawatts of electricity connecting Africa and Europe (Egypt–Cyprus–Greece)<ref>{{Cite web|url=https://www.euroafrica-interconnector.com/|title=EuroAfrica Interconnector|website=www.euroafrica-interconnector.com}}</ref><ref>[https://www.bloomberg.com/news/articles/2017-02-08/electricity-cable-aims-to-link-cyprus-egypt-greece Electricity Cable Aims to Link Cyprus, Egypt, Greece] Bloomberg, February 8, 2017</ref><ref>{{Cite web|url=https://www.financialmirror.com/2017/02/08/energy-euroafrica-2000mw-cable-boosts-egypt-cyprus-ties/|title=ENERGY: EuroAfrica 2,000MW cable boosts Egypt-Cyprus ties|date=February 8, 2017|website=Financial Mirror}}</ref><ref>{{Cite web|url=https://dailynewsegypt.com/2017/02/06/614506/|title=EEHC, Euro Africa Company sign MoU to conduct a feasibility study to link Egypt, Cyprus, Greece |website=dailynewsegypt.com |date=February 6, 2017}}</ref>
* 11 kV submarine replacement cables connecting [[Liu Ko Ngam]] and [[Pak Sha Tau Tsui]] at [[Kat O]], Northeast Hong Kong, approximately 880 m in length.<ref>{{cite web |date=22 January 2016 |title=Proposed 11kV Submarine Cables Replacement Connecting Liu Ko Ngam and Pak Sha Tau Tsui at Kat O |url=https://www.epd.gov.hk/eia/register/english/permit/ep4612013/documents/4wbseimsr/pdf/4wbseimsr.pdf |url-status=live |archive-url=https://web.archive.org/web/20220313211034/https://www.epd.gov.hk/eia/register/english/permit/ep4612013/documents/4wbseimsr/pdf/4wbseimsr.pdf |archive-date=13 March 2022 |access-date=13 March 2022 |website=[[Government of Hong Kong]]}}</ref>

==See also==
* [[Cable landing point]]
* [[Electric power transmission]]
* [[Single-wire earth return]]
* [[List of HVDC projects]]
* [[List of high voltage underground and submarine cables]]
* [[Electrical interconnector]], e.g. between grids
* [[Submarine communications cable]]

==References==
{{Reflist}}

==External links==
* [https://www.escaeu.org/ Subsea Cables UK - An organisation of submarine cable owners, operators and suppliers aimed at promoting marine safety and protecting cable installations on the UK continental shelf]
* [http://www.iscpc.org/ The International Cable Protection Committee]
* [http://www.subseacablesuk.org.uk/articles/submarine-power-cables/ Subsea Cables UK article on Submarine Power Cables]
* [http://www.4coffshore.com/windfarms/exportcables.aspx Export cables from Offshore Wind farms to Offshore substations]
* [http://www.4coffshore.com/windfarms/transmissions.aspx Transmission cables from Offshore converter to shore]
* [https://atlantic-cable.com/Cables/Power/index.htm History of the Atlantic Cable & Undersea Communications—Power Cables] (Cross sections of historic power cables)

{{DEFAULTSORT:Submarine Power Cable}}
[[Category:Submarine power cables| ]]
[[Category:Electric power transmission]]

[[de:Seekabel#Gleichstromkabel]]

Rip tide

2025-05-09T20:07:54Z

2.202.3.217: grammar

{{Short description|Current caused by the tide pulling water through an inlet}}
{{about|currents caused by the tide pulling water through an inlet|currents appearing near beaches|Rip current|other uses|Riptide (disambiguation)}}
[[File:US Navy 070412-N-9604C-005 Rescue swimmers wrestle with a rip tide during the kayaking event at the annual Naval Helicopter Aviation (NHA) Symposium 2007 Aircrew Competition.jpg|thumb|315x315px]]
A '''rip tide''', or '''riptide''', is a strong offshore current that is caused by the [[tide]] pulling water through an [[inlet]] along a [[Barrier island|barrier beach]], at a [[lagoon]] or inland [[marina]] where tide water flows steadily out to sea during [[ebb tide]]. It is a strong tidal flow of water within [[estuary|estuaries]] and other enclosed tidal areas. The riptides become the strongest where the flow is constricted. When there is a falling or ebbing tide, the outflow water is strongly flowing through an inlet toward the sea, especially once stabilised by [[jetties]].<ref>{{Cite news |url= https://www.surfertoday.com/surfing/the-differences-between-rip-currents-undertows-and-rip-tides |last= SurferToday |title= The differences between rip currents, undertows and rip tides |date= 2024 |accessdate= 3 January 2024 |language= en-us}}</ref>

== Dynamics ==
During these falling and ebbing tides, a riptide can carry a person far offshore. For example, the ebbing tide at [[Shinnecock Inlet]] in [[Southampton, New York]], extends more than {{Convert|300|m|}} offshore.<ref>{{Cite journal |last= Leatherman |first= Stephen P. |date= 2012-07-20 |title= Undertow, Rip Current, and Riptide |journal= Journal of Coastal Research |language= EN |volume= 283 |issue= 4 |pages= iii–v |doi= 10.2112/jcoastres-d-12-00052.1|s2cid=128555026 |doi-access=free }}</ref> Because of this, riptides are typically more powerful than [[rip currents]].

During slack tide, the water is motionless for a short period of time until the flooding or rising tide starts pushing the sea water landward through the inlet. Riptides also occur at constricted areas in [[Bay|bays]] and lagoons where there are no waves near an inlet.

These strong, reversing currents can also be termed '''ebb jets''', '''flood jet''', or '''tidal jets''' by coastal engineers because they carry large quantities of sand outward that form [[sandbars]] far out in the ocean or into the bay outside the inlet channel. The term "ebb jet" would be used for a tidal current leaving an enclosed tidal area, and "flood jet" for the equivalent tidal current entering it.

== Rip tide and rip currents ==
The term ''rip tide'' is often incorrectly used to refer to [[rip current]]s, which are not tidal flows. A rip current is a strong, narrow jet of water that moves away from the beach and into the ocean as a result of local [[Wind wave|wave motion]]. Rip currents can flow quickly, are unpredictable, and come about from what happens to waves as they interact with the shape of the sea bed. In contrast, a rip tide is caused by tidal movements, as opposed to wave action, and is a predictable rise and fall of the water level.<ref>{{Cite news |last= Showman |first= Sally |author2= KOIN 6 News staff |date= 2014-07-04 |title= Know your riptide, rip current and undertow |url= http://koin.com/2014/07/04/know-your-riptide-rip-current-and-undertow/ |archive-url=https://web.archive.org/web/20140713092059/http://koin.com/2014/07/04/know-your-riptide-rip-current-and-undertow/ |archive-date= 13 July 2014 |publisher= [[KOIN|KOIN 6]] |location= Portland, Oregon |access-date= 31 August 2017}}</ref>

The United States [[National Oceanic and Atmospheric Administration]] comments:

<blockquote>Rip currents are not rip tides. A specific type of current associated with [[tide]]s may include both the ebb and flood tidal currents that are caused by egress and ingress of the tide through [[inlet]]s and the mouths of [[Estuary|estuaries]], [[Bay|embayments]], and [[harbor]]s. These currents may cause [[drowning]] deaths, but these tidal currents or tidal jets are separate and distinct phenomena from rip currents. Recommended terms for these phenomena include ebb jet, flood jet, or tidal jet.<ref>[http://www.ripcurrents.noaa.gov/science.shtml "Rip Current Safety, Rip Current Science, Miscellaneous/General information, Rip Currents vs Rip Tides"]. National Weather Service, NOAA. Accessed 19 September 2017.</ref></blockquote>

== Surviving rip currents ==
People often drown by swimming directly against a rip current, which tires them out.<ref name="RipCurrentSurvivalGuide">{{cite web |title=Rip Current Survival Guide |url=https://oceantoday.noaa.gov/ripcurrentfeature/ |website=Ocean Today |publisher=National Oceanic and Atmospheric Administration |access-date=28 June 2023}}</ref> People are advised to not fight the current, which is too strong for any swimmer.<ref name="RipCurrentSurvivalGuide"/> People should not try to swim directly inwards, towards the beach.<ref name="RipCurrentSurvivalGuide"/> They should relax, and swim parallel to the beach.<ref name="RipCurrentSurvivalGuide"/> Eventually, they will swim clear of the rip current.<ref name="RipCurrentSurvivalGuide"/>

==See also==
* [[Rip current]]
* [[Baïne]]
* [[Tidal bore]]

==References==
<references />

{{Physical oceanography}}

[[Category:Oceanography]]
[[Category:Physical oceanography]]
[[Category:Bodies of water]]
[[Category:Tides]]