Many

tidal stream generator A tidal stream generator, often referred to as a tidal energy converter (TEC), is a machine that extracts energy from moving masses of water, in particular tides, although the term is often used in reference to machines designed to extract energy ...

s have been developed over the years to harness the power of tidal currents flowing around coastlines. These are also called tidal stream turbines (TST), tidal energy converters (TEC), or marine hydro-kinetic (MHK) generation. These turbines operate on a similar principle to

wind turbine A wind turbine is a device that converts the kinetic energy of wind into electrical energy. Hundreds of thousands of large turbines, in installations known as wind farms, now generate over 650 gigawatts of power, with 60 GW added each year. W ...

s, but are designed to work in a fluid approximately 800 times more dense than air which is moving at a slower velocity. Note that

tidal barrage A tidal barrage is a dam-like structure used to capture the energy from masses of water moving in and out of a bay or river due to tidal forces. Instead of damming water on one side like a conventional dam, a tidal barrage allows water to flow ...

s or lagoons operate on a different principle, generating power by impounding the rising and falling tide. Lots of different technology variants have been tested, and there has not been convergence on a predominant typology. Most have been horizontal-axis, like wind turbines, but with 2, 3, or more blades and either mounted on a seabed fixed foundation or on a floating platform. In addition, vertical-axis turbines and tidal kites are also being developed. Historically, development has largely been focused around Europe, but devices have been built and tested in North America – including at the Fundy Ocean Research Centre for Energy (FORCE), Japan, and elsewhere. The

European Marine Energy Centre The European Marine Energy Centre (EMEC) Ltd is a UKAS accredited test and research center focusing on wave and tidal power development based in the Orkney Islands, UK. The centre provides developers with the opportunity to test full-scale grid ...

(EMEC) was set up in

Orkney Orkney (; sco, Orkney; on, Orkneyjar; nrn, Orknøjar), also known as the Orkney Islands, is an archipelago in the Northern Isles of Scotland, situated off the north coast of the island of Great Britain. Orkney is 10 miles (16 km) nort ...

in 2003, and developed a tidal test site in the Fall of Warness, to the west of the island of

Eday Eday (, sco, Aidee) is one of the islands of Orkney, which are located to the north of the Scottish mainland. One of the North Isles, Eday is about from the Orkney Mainland. With an area of , it is the ninth-largest island of the archipelago. ...

. The site opened in 2006, and EMEC was granted a license in 2016 to test up to 10 MW of tidal stream devices, and has since hosted the testing of many of these devices. There have been various acquisitions of technology developers over the years. Many of the companies are no longer trading, or have ceased development of tidal-stream turbines. However, the first pre-commercial array demonstration projects have been operating since around 2016. Building on this, commercial arrays are expected to be operational by around 2027, at EMEC, Morlais and elsewhere.

Development timeline

Key historical milestones in the development of tidal-stream turbines are summarised below: * The 300 kW

Marine Current Turbines Marine Current Turbines Ltd (MCT), is a United Kingdom-based company which is developing tidal stream generators. It is owned by the German automation company, Siemens. History MCT was founded in 2000 to develop ideas of tidal power develo ...

(MCT) SeaFlow turbine was installed in summer 2003 and tested off the coast of

Lynmouth Lynmouth is a village in Devon, England, on the northern edge of Exmoor. The village straddles the confluence of the West Lyn and East Lyn rivers, in a gorge below Lynton, which was the only place to expand to once Lynmouth became as b ...

, Devon, England. * In 2004, the world's first tidal-stream turbine was connected to an electricity grid, the 300 kW Hammerfest Strøm HS300, located in the waters of

Kvalsundet Kvalsundet is a strait in Hammerfest Municipality in Troms og Finnmark county, Norway. The strait separates the island of Kvaløya from the mainland. The strait is crossed by Kvalsund Bridge, which connects Kvaløya to the mainland and is the wor ...

, Finnmark, Norway. * The first tidal stream turbine test site was constructed in 2005 and opened in 2006, in the Fall of Wanress to the west of Eday, Orkney, part of the European Marine Energy Centre. * The significantly more powerful, 1.2 MW MCT

SeaGen SeaGen was the world's first large scale commercial tidal stream generator. It was four times more powerful than any other tidal stream generator in the world at the time of installation. It was successfully decommissioned by SIMEC Atlant ...

turbine was installed in

Strangford Lough Strangford Lough (from Old Norse ''Strangr Fjörðr'', meaning "strong sea-inlet"PlaceNames N ...

, Northern Ireland, in May 2008 and grid connected in July. * Also in May 2008, OpenHydro was the first tidal turbine connected to the National Grid in Great Britain (GB). The 250 kW device was tested in the Fall of Warness,

, Orkney. * Verdant Power installed six 35 kW turbines in New York's

East River The East River is a saltwater tidal estuary in New York City. The waterway, which is actually not a river despite its name, connects Upper New York Bay on its south end to Long Island Sound on its north end. It separates the borough of Que ...

, supplying power to two local businesses, claimed as the world's first tidal array. * In August 2016, Nova Innovation installed a second 100 kW turbine in the

Bluemull Sound Bluemull Sound is the strait between Unst and Yell in Shetland's North Isles. A ferry service crosses it regularly. Cullivoe is on the Yell side, and the island of Linga A lingam ( sa, लिङ्ग , lit. "sign, symbol or mark"), sometim ...

, Shetland, connected to the GB Grid, also claimed as the world's first tidal array. * A dedicated site for testing tidal stream turbines was pre-consented at the

in 2016, to simplify the process for developers testing devices. * Phase 1 of the

MeyGen MeyGen (full name MeyGen tidal energy project) will be the world's largest tidal energy plant, which is currently in construction. The first phase of the project uses four 1.5MW turbines with rotor diameter turbines submerged on the seabed. The ...

project was commissioned in 2017, with four turbines totaling 6 MW installed, making it the largest tidal array to date.

Key companies and turbines

Many companies have focused on the development of technology to harness tidal stream energy. A non-exhaustive list of key companies is given below.

Alstom

French manufacturer

Alstom Alstom SA is a French multinational rolling stock manufacturer operating worldwide in rail transport markets, active in the fields of passenger transportation, signalling, and locomotives, with products including the AGV, TGV, Eurostar, Av ...

acquired Tidal Generation Ltd in 2012, but this part of the business was sold to

General Electric General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable energ ...

in 2015.

Andritz Hydro Hammerfest

Hammerfest Strøm AS was a Norwegian developer of tidal stream turbines, based in

Hammerfest Hammerfest (; sme, Hámmerfeasta ) is a municipality in Troms og Finnmark county, Norway. Hammerfest is the northernmost town in the world with more than 10,000 inhabitants. The administrative centre of the municipality is the town of Hammerfe ...

. In 2010, Austrian hydropower company

Andritz AG Andritz AG is an international technology group, offering plants, equipment, systems and services for various industries. The group's headquarters are in Graz, Austria. The group gets its name from the district of Andritz in which it is locate ...

bought one third of the shares. In 2012, Andritz became the majority stakeholder and rebranded the company Andritz Hydro Hammerfest. In November 2003, Hammerfest Strøm installed their HS300 turbine in

, Norway. This 300 kW prototype was a 20 m diameter three-bladed horizontal-axis turbine. It sat on a monopile foundation in 50 m deep water. In 2003, the project was reported to have cost US$11m. The HS300 turbine was connected to the grid in 2014, and operated for over 16,000 hours before it was decommissioned in 2011 and removed in 2012. A more powerful 1MW device was then tested at EMEC from 2012. The HS1000 was also a 20 m diameter three-bladed horizontal-axis turbine, installed at the Fall of Warness test site in December 2011. Three Andritz Hydro Hammerfest AH1000 MK1 turbines were installed as part of phase 1 of the

project in 2016. These turbines are still three-bladed, but with an 18 m diameter rotor and each rated at 1.5 MW.

BigMoon Power

BigMoon Power is a Canadian company founded in 2015 developing a floating tidal stream generator. The concept is designed to be simple, with an optimised waterwheel (called a Kinetic Keel) mounted between two hulls of a barge, moored by foundations build from old train cars filled with concrete. BigMoon plan to build and install 18 devices, each 0.5 MW, at in the Bay of Fundy at FORCE. As part of the contract to test at FORCE Berth D, BigMoon has to remove before the end of 2024 the OpenHydro turbine that was abandoned there in July 2018 when that company went into administration.

Flumill

Flumill AS is a Norwegian developer of an unconventional tidal stream turbine. It consists of two counter-rotating helical screws made from

fiberglass Fiberglass (American English) or fibreglass (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass cl ...

, each attached to a gear-less permanent magnet generator. The unit is mounted to the seabed and held up by a buoyant float/fin. In 2011 Flumill was the first turbine to be tested at the EMEC Shapinsay Sound non-grid-connected test site, after tow tests in Tromøysund,

Arendal Arendal () is a municipality in Agder county in southeastern Norway. Arendal belongs to the region of Sørlandet. The administrative centre of the municipality is the city of Arendal (which is also the seat of Agder county). Some of the not ...

, Norway. This device was nominally rated at 1.2 kW in the 1.5 m/s currents of Shapinsay Sound, although it could potentially generate 600 kW in faster flows. A phase 2 Flumill tidal device is currently being developed, where the screws and generators are mounted from a catamaran barge.

General Electric

In 2015, GE acquired the energy assets from

which included the business originally developed by Tidal Generation Ltd. In 2024,

GE Vernova General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable ener ...

signed a MoU with Proteus Marine Renewables to supply electrical systems for their tidal turbines.

HydroQuest

HydroQuest is a French developer of vertical-axis river current and tidal stream turbines, based in

Grenoble lat, Gratianopolis , commune status = Prefecture and commune , image = Panorama grenoble.png , image size = , caption = From upper left: Panorama of the city, Grenoble’s cable cars, place Saint- ...

. In 2013, HydroQuest installed a turbine in the

Oyapock The Oyapock or Oiapoque (; ; ) is a long river in South America that forms most of the border between the French overseas department of French Guiana and the Brazilian state of Amapá. Course The Oyapock runs through the Guianan moist for ...

river in

French Guiana French Guiana ( or ; french: link=no, Guyane ; gcr, label=French Guianese Creole, Lagwiyann ) is an overseas departments and regions of France, overseas department/region and single territorial collectivity of France on the northern Atlantic ...

, powering the 200 inhabitants of the

Camopi Camopi is a commune of French Guiana, an overseas region and department of France located in South America. Camopi is mainly inhabited by Amerindians of the Wayampi and Teko tribes. History In 1738, a Jesuit mission opened on the river O ...

village. The also company tested a 40 kW HydroQuest 1.40 in the

Loire The Loire (, also ; ; oc, Léger, ; la, Liger) is the longest river in France and the 171st longest in the world. With a length of , it drains , more than a fifth of France's land, while its average discharge is only half that of the Rhôn ...

river in

Orléans Orléans (;"Orleans"
(US) and Paimpol–Bréhat between April 2019 and December 2021. It was constructed by

Constructions Mécaniques de Normandie Construction is the process of producing buildings and other infrastructure. Construction also may refer to: * Additional physical/mechanical senses: ** Offshore construction, the installation of structures in marine environments * Primarily abst ...

(CMN) in Cherbourg, and comprised four vertical axis turbines each with three blades, mounted in pairs on two shafts. The device weighed 1500 tonnes. In collaboration with CMN and renewable energy company Qair, Hydroquest are developing the FloWatt project. This will comprise seven Hydroquest turbine units, each rated at 2.5 MW, to be installed at

Raz Blanchard The Alderney Race is a strait that runs between Alderney and Cap de la Hague, a cape at the northwestern tip of the Cotentin Peninsula in Normandy. A strong current runs through the race north of the Passage de la Déroute, a treacherous passage ...

, Brittany by 2026. The turbines will be again be constructed by CMN in Cherbourg. Each unit is 21 m tall, 26 m wide with a pair of three-bladed turbines mounted on a vertical shaft either side of a central structure. The French Government is supporting the project with €65m funding and dedicated revenue support for the electricity generated. In September 2023, Hydroquest launched a crowdfunding campaign, seeking to raise a further €1.5m for the project.

LHD New Energy Corporation

LHD New Energy Corporation have developed the Zhoushan tidal power station near Xiushan island,

Daishan County () is a county under the jurisdiction of Zhoushan, Zhejiang Province. It covers a land area of and has a population of 200,000. The postal code is 316200, and the county seat is located on 88 Renmin Road, Gaoting Town. The county is located i ...

, China. This platform above the sea is connected to land by a bridge. In 2016, the first two turbines were installed and connected to the grid, rated at 400 kW and 600 kW. In December 2018, two further turbines were added, a 300 kW horizontal-axis and a 400 kW vertical-axis, taking the total installed capacity to 1.7 MW.

Magallanes Renovables

Magallanes Renovables, S.L. is a Spanish developer of floating tidal energy devices, set up in 2009. They have tested a grid-connected 1.5 MW ATIR device at EMEC since 2019, having previously tested a small scale device at the EMEC nursery test site in Shapinsay Sound, although this was not grid-connected. Magallanes Thas been awarded Contracts for Difference (CfD) to supply subsidised electricity to the GB National Grid, at Morlais and at EMEC.

Marine Current Turbines

Marine Current Turbines (MCT) was a

Bristol Bristol () is a city, ceremonial county and unitary authority in England. Situated on the River Avon, it is bordered by the ceremonial counties of Gloucestershire to the north and Somerset to the south. Bristol is the most populous city i ...

-based company that developed seabed mounted tidal-stream turbines. In June 2003, MCT installed the 300 kW Seaflow turbine in

, Devon. The larger 1.2 MW SeaGen turbine was installed in

Strangford Lough Strangford Lough (from Old Norse ''Strangr Fjörðr'', meaning "strong sea-inlet"PlaceNames N ...

in May 2008, and connected tot the Irish electricity grid in July. It was decommissioned in stages between May 2016 and July 2019, having exported 11.6 GWh of electricity.

Minesto

Minesto AB is a Swedish developer of tidal kite turbines, based in Gothenburg. The company tested a 500 kW Deep Green DG500 turbine in the Holyhead Deep off the coast of

Anglesey Anglesey (; cy, (Ynys) Môn ) is an island off the north-west coast of Wales. It forms a Local government in Wales, principal area known as the Isle of Anglesey, that includes Holy Island, Anglesey, Holy Island across the narrow Cymyran Strai ...

, North Wales in 2018 and 2019. In 2022, they installed two 100 kW Dragon 4 turbines at

Vestmanna Vestmanna is a town in the Faroe Islands on the west of the island of Streymoy. It was formerly a ferry port, until an undersea tunnel, the Vágatunnilin, was built from Vágar to Kvívík and Stykkið further south on Streymoy. The cliffs west ...

sund in the

Faroe Islands The Faroe Islands ( ), or simply the Faroes ( fo, Føroyar ; da, Færøerne ), are a North Atlantic archipelago, island group and an autonomous territory of the Danish Realm, Kingdom of Denmark. They are located north-northwest of Scotlan ...

, and are planning to install a 1.2 MW Dragon 12 turbine there in 2024.

Nova Innovation

Nova Innovation Ltd is an

Edinburgh Edinburgh ( ; gd, Dùn Èideann ) is the capital city of Scotland and one of its 32 Council areas of Scotland, council areas. Historically part of the county of Midlothian (interchangeably Edinburghshire before 1921), it is located in Lothian ...

-based developer of small bed-mounted tidal-stream turbines. They deployed their first 30 kW turbine in the

, Shetland, and have operated an array of up-to 6 of their 100 kW turbines in the Bluemull Sound since 2016.

Ocean Renewable Power Company

Ocean Renewable Power Company (ORPC, Inc.) is a developer of cross-flow turbines to harness river, tidal and ocean currents, based in

Portland, Maine Portland is the largest city in the U.S. state of Maine and the seat of Cumberland County. Portland's population was 68,408 in April 2020. The Greater Portland metropolitan area is home to over half a million people, the 104th-largest metro ...

OpenHydro

OpenHydro Group Ltd was an Irish developer of tidal stream turbines, acquired by Naval Energies (then DCNS) in 2013, but ceased trading in 2018. OpenHydro developed a novel open-centred horizontal-axis turbine, surrounded by a ducting shroud. Various iterations of the OpenHydro turbines were tested in Scotland, France and Canada.

Orbital Marine Power

Orbital Marine Power Ltd is an

-based developer of floating tidal stream turbines that have twin rotors either side of a long tubular hull. Their third-generation turbine, the 2 MW Orbital O2 has been deployed at the Fall of Warness since 2021. The company was founded in 2002 as Scotrenewables Tidal Power Ltd, but rebranded in 2019.

Proteus Marine Renewables

In October 2022, Proteus Marine Renewables (PMR) was formed through a

management buyout A management buyout (MBO) is a form of acquisition in which a company's existing managers acquire a large part, or all, of the company, whether from a parent company or individual. Management-, and/or leveraged buyout became noted phenomena of ...

of the Advanced Tidal Engineering and Services division of SIMEC Atlantis Energy, now SAE Renewables. SAE remain a minority shareholder in Proteus, and Proteus will continue to support the

tidal farm. The company is based at Bath & Bristol Science Park,

, England. Proteus is a majority shareholder in '','' which is planning to deploy a 12 MW pilot tidal farm at

in 2025. The NH1 project will consist of four PMR AR3000 turbines, each rated at 3 MW. In August 2024, PMR started building an AR1100 turbine to be deployed in the Naru Strait to power the

Gotō Islands The are Japanese islands in the East China Sea, off the western coast of Kyūshū. They are part of Nagasaki Prefecture. Geography There are 140 islands, including five main ones: , , , , and . The group of islands runs approximately ...

in Japan. This is an upgrade of the AR500 turbine with added pitch and yaw mechanisms, and uprated to 1.1 MW. The AR500 was previously tested in the Naru Strait from February 2021 to December 2023. In November 2024, Proteus signed a MoU with

SKF AB SKF (Swedish: ''Svenska Kullagerfabriken''; 'Swedish Ball Bearing Factory') is a Swedish bearing and seal manufacturing company founded in Gothenburg, Sweden, in 1907. The company manufactures and supplies bearings, seals, lubrication and ...

to supply the rotating equipment and

to supply electrical systems for their tidal turbines.

Pulse Tidal

Pulse Tidal Ltd was an English tidal stream developer, formed in 2007 after 10years of development. They developed a fully-submerged oscillating hydrofoil device, designed to work in shallow water, with horizontal blades that moved up and down in the passing current. A 100 kW, prototype was installed in 2009 at

Immingham Dock The Port of Immingham, also known as Immingham Dock, is a major port on the east coast of England, located on the south bank of the Humber Estuary in the town of Immingham, Lincolnshire. In 2019, the Port of Grimsby & Immingham was the largest p ...

, in the

Humber estuary The Humber is a large tidal estuary on the east coast of Northern England. It is formed at Trent Falls, Faxfleet, by the confluence of the tidal rivers Ouse and Trent. From there to the North Sea, it forms part of the boundary between ...

, which could generate up to 150 kW for a nearby chemicals plant. The company was awarded €8m in European funding to develop the first commercial prototype, expected to be rated at 1.2 MW, and deployed at

, Devon, where Pulse Tidal had been awarded a seabed lease from the

Crown Estate The Crown Estate is a collection of lands and holdings in the United Kingdom belonging to the British monarch as a corporation sole, making it "the sovereign's public estate", which is neither government property nor part of the monarch's priv ...

. The company was also developing plans for the Kylerhea Narrows between the mainland of Scotland and

Skye The Isle of Skye, or simply Skye (; gd, An t-Eilean Sgitheanach or ; sco, Isle o Skye), is the largest and northernmost of the major islands in the Inner Hebrides of Scotland. The island's peninsulas radiate from a mountainous hub dominated ...

. Pulse Tidal was liquidated in 2014.

Sabella

Sabella SAS was a French

SME SME may refer to: Economics * Small and medium-sized enterprises * Socialist market economy, an economic system of China Organizations Music * SME Limited, UK audio turntable manufacturer * Sony Music Entertainment, US * Spontaneous Music En ...

based in

Quimper Quimper (, ; br, Kemper ; la, Civitas Aquilonia or ) is a commune and prefecture of the Finistère department of Brittany in northwestern France. Administration Quimper is the prefecture (capital) of the Finistère department. Geography T ...

, Brittany that has been developing tidal turbines since 2008, however the company was placed into receivership in October 2023. The company had developed two main variants of their technology. The D03 was a 30 kW horizontal-axis turbine, with a six-bladed rotor 3 m in diameter, hence the name. It was tested in the

Odet The Odet ( br, Oded) is a river in western France (Finistère department), which runs from Saint-Goazec (near Leuhan, in the Montagnes Noires of Brittany) into the Atlantic Ocean at Bénodet. The name of the town of Bénodet comes from the ri ...

estuary in 2008, but not grid connected. The turbine weighed 7 tonnes, and sat on a gravity base in around 25 m deep water. The larger 1 MW D10 turbine was then developed, and tested in the Fromveur Passage, Brittany from June 2015. After hackers interrupted the communications link with the turbine, it began supplying power to the grid in

Ushant Ushant (; br, Eusa, ; french: Ouessant, ) is a French island at the southwestern end of the English Channel which marks the westernmost point of metropolitan France. It belongs to Brittany and, in medieval terms, Léon. In lower tiers of gover ...

on 5 November 2015. It was redeployed for a third test campaign in April 2022, In October 2024, Inyanga Marine Energy took over the D10 turbine operation, securing permission to operate it until August 2028.

SIMEC Atlantis Energy

SIMEC Atlantis Energy Ltd (now just SAE) is a renewable energy company which is developing the

tidal array in the

Pentland Firth The Pentland Firth ( gd, An Caol Arcach, meaning the Orcadian Strait) is a strait which separates the Orkney Islands from Caithness in the north of Scotland. Despite the name, it is not a firth. Etymology The name is presumed to be a corruption ...

between the Scottish mainland and Orkney. Since 2017, this has operated with 4× 1.5 MW tidal turbines, making it the largest tidal-stream array worldwide. The next phases could see a further 50 MW installed by 2028. The company was founded as Atlantis Resources, and developed the 1.5 MW AR1500 turbine, a three-bladed horizontal-axis seabed mounded device, three of which are installed at

. They also built a smaller 500 kW AR500 turbine in Scotland, which was shipped to Japan and installed off Naru Island, part of the

. It reportedly generated 10 MWh in the first 10 days of operation in early 2021.

Sustainable Marine Energy

Sustainable Marine Energy Ltd (SME) was a developer of floating tidal stream turbines, founded in 2012 but went into administration in August 2023. Originally based in London, it moved to

East Cowes East Cowes is a town and civil parish in the north of the Isle of Wight, on the east bank of the River Medina, next to its west bank neighbour Cowes. The two towns are connected by the Cowes Floating Bridge, a chain ferry operated by the Is ...

, Isle of Wight in 2013. The company then moved its operational base to

Kirkwall Kirkwall ( sco, Kirkwaa, gd, Bàgh na h-Eaglaise, nrn, Kirkavå) is the largest town in Orkney, an archipelago to the north of mainland Scotland. The name Kirkwall comes from the Norse name (''Church Bay''), which later changed to ''Kirkv ...

in Orkney in 2016. By 2017, the head office had been relocated to ''La Belle Esperance'', a barge moored on The Shore,

Leith Leith (; gd, Lìte) is a port area in the north of the city of Edinburgh, Scotland, founded at the mouth of the Water of Leith. In 2021, it was ranked by ''Time Out'' as one of the top five neighbourhoods to live in the world. The earliest ...

, Edinburgh. Their first platform, PLAT-O, was a submerged mid-water-column device, with two 50 kW Schottel SIT turbines, mounted between three buoyant hulls. It was initially tested in

The Solent The Solent ( ) is a strait between the Isle of Wight and Great Britain. It is about long and varies in width between , although the Hurst Spit which projects into the Solent narrows the sea crossing between Hurst Castle and Colwell Bay t ...

, before being tested at EMEC in 2016. The floating PLAT-I 4.63 was developed for community-scale deployments in inshore waters. It had four 6.3 m diameter turbines mounted on a floating boat-like structure. It was first tested at the

Falls of Lora The Falls of Lora is a tidal race which forms at the mouth of Loch Etive when a particularly high tide runs out from the loch. They form white water rapids for two to five days either side of the spring tides.Nova Scotia Nova Scotia ( ; ; ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. Nova Scotia is Latin for "New Scotland". Most of the population are native En ...

in 2018. An upgraded PLAT-I 6.4, with six 4 m diameter rotors, totaling 420 kW, was built by A.F. Theriault & Son Ltd. in Meteghan, Nova Scotia in 2021. The turbine was tested at FORCE in the Grand Passage, delivering the first floating tidal power to the Canadian grid in April 2022. SME developed the Pempa’q project at FORCE which was to comprise an array of the PLAT-I turbines, with up to 9 MW installed. The project received C$28.5million in funding from the Government of Canada, however it was cancelled in 2023, citing federal red tape. SME placed the turbines into storage and removed all of the equipment from the seabed. However, one of the turbines broke its moorings and washed ashore in November 2023. In October 2022, the company split out its anchoring solutions as Swift Anchors, with the aim to focus on different technologies including Floating offshore wind.

Tidal Energy Ltd

Tidal Energy Ltd (TEL) was a tidal stream developer based in Cardiff, Wales. They developed a three-bladed horizontal-axis turbine mounted on a 16 m long triangular gravity base. To increase reliability, a simple fixed-pitch blade design was used. A 400 kW prototype was installed in Ramsey Sound, Wales in December 2015 after sitting on the quayside at

Pembroke Dock Pembroke Dock ( cy, Doc Penfro) is a town and a community in Pembrokeshire, South West Wales, northwest of Pembroke on the banks of the River Cleddau. Originally Paterchurch, a small fishing village, Pembroke Dock town expanded rapidly follow ...

for over a year. In March 2016, the turbine developed "an intermittent fault with an active sonar" followed by a mechanical defect which prevented it generating. After the company went into administration in October, the Welsh Government sought a buyer for the turbine in December 2016. There were plans to remove the turbine as part of the Anglo-French ''Tidal Stream Industry Energiser Project'' (TIGER) project, and examine the reasons for the failures. The Ramsey Sound site was also to be redeveloped by Cambrian Offshore South West, with a new turbine of up to 1 MW installed. The triangular base frame was designed to support three turbines, although only a single turbine was tested. Eco2 in conjunction with TEL had planned to install an array of nine devices

St David's Head St David's Head ( cy, Penmaen Dewi) is a headland in the Pembrokeshire Coast National Park, southwest Wales, which marks the divide between the Irish Sea and the Celtic Sea. It is noted for its wildflowers and wildlife, and for the remains of a ...

, to the north of Ramsey Sound. TGL DeepGen III at Hatston Pier

Tidal Generation Ltd

Tidal Generation Ltd (TGL) was a

-based developer of tidal stream turbines, founded in 2005. It was acquired by

Rolls-Royce Rolls-Royce (always hyphenated) may refer to: * Rolls-Royce Limited, a British manufacturer of cars and later aero engines, founded in 1906, now defunct Automobiles * Rolls-Royce Motor Cars, the current car manufacturing company incorporated ...

, before being sold to

in 2012. Then in 2015,

acquired Alstom's energy division, including TGL. In 2021 French tidal developer Sabella acquired General Electric's tidal energy assets, including those developed by TGL, Rolls-Royce and Alstom. TGL tested a 500 kW turbine at EMEC from September 2010 as part of the Deep-Gen III project. This was the first turbine installed at EMEC that was eligible for

Renewables Obligation Certificates The Renewables Obligation (RO) is designed to encourage generation of electricity from eligible renewable sources in the United Kingdom. It was introduced in England and Wales and in a different form (the Renewables Obligation (Scotland)) in S ...

. By September 2012, it had generated over 250 MWh of electricity which was supplied to the local grid. An upgraded 1 MW Deep-Gen IV turbine was developed while part of Rolls-Royce within the ''Reliable Data Acquisition Platform for Tidal'' (ReDAPT) project, partly funded by the

Energy Technologies Institute The Energy Technologies Institute (ETI) was a public-private partnership between global energy and engineering companies and the UK Government that was established in the United Kingdom in 2007. The government set up the ETI following an announcem ...

. The turbine rotor was 18 m in diameter, mounted on a 22 m long nacelle, with a mass of under 150 t. It had cut-in, rated, and maximum flow speeds of 1 m/s, 2.7 m/s, and 5 m/s respectively. In 2014, a 1.4 MW turbine was proposed, again with an 18 m diameter rotor. It was marketed as the Oceade™ 18 – 1.4 MW, but was never built. The TGL turbines were a three-bladed horizontal-axis design which could yaw to face the incoming tide, driven by a thruster on the rear of the nacelle. They nacelle of the turbine was buoyant, which allowed it to towed to site then installed onto the subsea tripod foundation using a winch system operated from small workboats.

Tocardo

Tocardo BV is a Dutch tidal stream turbine developer, jointly owned by QED Naval and Hydrowing as of January 2020. The company began developing their technology in 1999. The Tocardo turbines are two-bladed horizontal-axis with direct-drive generators. A prototype T1 turbine was tested in the sluice of the

Afsluitdijk The ''Afsluitdijk'' (; fry, Ofslútdyk; nds-nl, Ofsluutdiek; en, "Closure Dyke") is a major dam and causeway in the Netherlands. It was constructed between 1927 and 1932 and runs from Den Oever in North Holland province to the village o ...

(Closure Dyke) in the Netherlands in 2008. This was 2.8 m in diameter and rated at 45 kW. In early 2015, a further three Tocardo T1 turbines were installed, each rated at 100 kW. In 2015, five Tocardo T2 turbines were installed on the

Oosterscheldekering The Oosterscheldekering ( English: Eastern Scheldt storm surge barrier), between the islands Schouwen-Duiveland and Noord-Beveland, is the largest of the Delta Works, a series of dams and storm surge barriers, designed to protect the Netherlands ...

(Eastern Scheldt storm surge barrier) also in the Netherlands. These started generating electricity to the Dutch grid in 2016. They were mounted on a frame supported by the road bridge which could rotate to lift all of the turbines out the water simultaneously. Each turbine was 5.26 m in diameter (87 m² swept area) and rated at 250 kW for a total power of 1.25 MW. The project was decommissioned after eight years of operation in 2023. In the ''BlueTec'' project a floating platform was moored near the Dutch island of

Texel Texel (; Texels dialect: ) is a municipality and an island with a population of 13,643 in North Holland, Netherlands. It is the largest and most populated island of the West Frisian Islands in the Wadden Sea. The island is situated north of ...

, with a Tocardo turbine mounted beneath it. It was initially installed in summer 2015 with a 100 kW T1 turbine, then reinstalled in early 2016 with a T2 turbine, and provided power to the local electricity grid. The turbine was launched from

Den Helder Den Helder () is a municipality and a city in the Netherlands, in the province of North Holland. Den Helder occupies the northernmost point of the North Holland peninsula. It is home to the country's main naval base. From here the Royal TESO ...

, and there were plans to also test a 50 kW Schottle turbine on the platform. Three Tocardo T1 turbines were integrated onto the 240 kW QED Naval ''Subhub'' community demonstrator platform in late 2021, with a plan to test the turbine in

near

Yarmouth, Isle of Wight Yarmouth is a town, port and civil parish in the west of the Isle of Wight, off the south coast of England. The town is named for its location at the mouth of the small Western Yar river. The town grew near the river crossing, originally a ferr ...

, UK. The next generation of Tocardo T3 turbines are planned to be used on the tidal projects by Hydrowing and Môr Energy at Morlais, Wales.

Verdant Power

Verdant Power, Inc is a developer of tidal stream turbines, based in New York, USA. They have tested turbines in the

since 2006. An array of six 35 kW turbines supplied power to two local businesses from May 2007 to October 2008. An upgraded platform with three turbines was installed in October 2020.

Voith Hydro

Voith Hydro Ocean Current Technologies GmbH was a joint venture between

Voith Hydro The Voith Group is a German manufacturer of machines for the pulp and paper industry, technical equipment for hydropower plants and drive and braking systems. The family-owned company, which operates worldwide and has its headquarters in Heide ...

and

RWE Innogy Innogy SE was an energy company based in Essen, Germany. It is now merged and integrated into German energy company E.ON. History The company was created on 1 April 2016, by splitting the renewable, network and retail businesses of RWE into a ...

that developed tidal stream turbines, however Innogy sold their stake in November 2013. The 110 kW HyTide 110–5.3 turbine was tested in southern

South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korea, Korean Peninsula and sharing a Korean Demilitarized Zone, land border with North Korea. Its western border is formed ...

, near

Jindo island Jindo Island is the third largest island in South Korea. Together with a group of much smaller islands, it forms Jindo County. It is located in South Jeolla province, just off the southwest corner of the Korean peninsula. The island is separated ...

in 2010, a 1/3rd scale prototype. This had a 5.33 m diameter rotor, 22 m² swept area. The turbine was designed to be simple, with a direct-drive generator (without gearbox) and no yaw or blade pitch adjustment. It also had no dynamic seals, thus the generator was cooled by seawater. The turbine was prototype certified by

Germanischer Lloyd The Germanischer Lloyd SE was a classification society based in the city of Hamburg, Germany. It ceased to exist as an independent entity in September 2013 as a result of its merger with Norway's DNV (Det Norske Veritas) to become DNV GL. Befor ...

. A full-scale 1 MW horizontal-axis turbine was then tested at EMEC between 2013 and 2015. The HyTide 1000 had a 13 m diameter rotor (133 m² swept area), and weighed around 200 tonnes. It was installed by ''SLA Offshore'' in September 2013, from the DP II vessel ''MV Lone''. Voith also acquired the 250 kW

Islay LIMPET Islay LIMPET was the world's first commercial wave power device and was connected to the United Kingdom's National Grid. History Islay LIMPET (Land Installed Marine Power Energy Transmitter) was developed and operated by Wavegen in cooperati ...

wave power Wave power is the capture of energy of wind waves to do useful work – for example, electricity generation, water desalination, or pumping water. A machine that exploits wave power is a wave energy converter (WEC). Waves are generated by w ...

station in 2005.

Zhejiang University

Zhejiang University has installed three tidal stream turbines to the north of Zhairuoshan Island (), in the

Zhoushan Zhoushan , formerly romanized as Chusan, is an urbanized archipelago with the administrative status of a prefecture-level city in the eastern Chinese province of Zhejiang. It consists of an archipelago of islands at the southern mouth of ...

archipelago. A 60 kW turbine was installed in 2014, a 120 kW turbine deployed in 2015, and a 600 kW turbine in 2018.

List of grid-connected tidal stream generators

Over the years, many different tidal stream turbines have been deployed and tested at sea, and have delivered power to the local electricity grid. A non-exhaustive list is given in the table below, along with other notable devices. As most of these were development and test versions, they were removed for periods of time for maintenance or upgrades.

Notes

References

{{Ocean energy Tidal power Tidal power in Canada Tidal power companies of the United Kingdom Tidal power in France Renewable energy companies Tidal power in Wales