Tidal Stream Energy: Key Companies and Turbine Technologies

Tidal stream energy harnesses the kinetic energy of moving water currents—similar to how wind turbines capture wind—to generate clean, predictable electricity. Unlike tidal barrages that require dams, tidal stream technology uses submerged or floating turbines to extract power from the natural flow of the ocean. Over the last two decades, a diverse array of global companies has experimented with various designs, from massive seabed-mounted rotors to innovative floating kites.

Key Facts

MeyGen is currently the world's largest tidal-stream array, utilizing 1.5 MW turbines in Scotland's Pentland Firth.
Horizontal-axis turbines (like the AR1500) are the most common, though vertical-axis and helical screw designs exist.
Floating platforms, such as those developed by Orbital Marine Power, allow for easier maintenance compared to seabed-mounted units.
EMEC (European Marine Energy Centre) serves as a primary global hub for testing and certifying new tidal prototypes.
Tidal Kites, developed by companies like Minesto, use a "flight" motion to increase the speed of water passing through the turbine.

Pioneers in Seabed-Mounted Turbines

Seabed-mounted turbines are fixed directly to the ocean floor, often using monopiles or gravity bases to withstand powerful currents. Andritz Hydro Hammerfest has been a significant player, evolving from the 300 kW HS300 prototype in Norway to the 1.5 MW Mk1 turbines used in the MeyGen project, which have generated over 80GWh of electricity.

Similarly, SIMEC Atlantis Energy (now Ampeak Energy) developed the AR1500, a three-bladed horizontal-axis device. They also deployed the AR500 in Japan, which produced 10 MWh in its first ten days of operation in 2021.

Other notable seabed efforts include Marine Current Turbines, whose SeaGen turbine in Strangford Lough exported 11.6 GWh before its decommissioning, and Tidal Energy Ltd, which tested a 400 kW prototype in Ramsey Sound, Wales.

Floating and Innovative Designs

To reduce installation costs and simplify maintenance, several companies have moved toward floating structures. Orbital Marine Power utilizes a long tubular hull with twin rotors; their 2 MW Orbital O2 has been operational at the Fall of Warness since 2021.

Magallanes Renovables tested a 1.5 MW ATIR device at EMEC, while Sustainable Marine Energy (SME) developed the PLAT-I series. The PLAT-I 6.4, featuring six rotors totaling 420 kW, provided the first floating tidal power to the Canadian grid in 2022.

Beyond traditional rotors, Minesto employs "tidal kites" that fly in a figure-eight pattern to accelerate water flow. Their Dragon 4 turbines (100 kW) are currently deployed in the Faroe Islands.

Specialized and Unconventional Technologies

Some developers have moved away from the standard three-blade design. Flumill utilizes counter-rotating helical screws made of fiberglass, while HydroQuest focuses on vertical-axis turbines, deploying units in both French rivers and the Paimpol–Bréhat tidal site.

In China, LHD New Energy Corporation and Zhejiang University have advanced the field. LHD's Zhoushan station features a mix of horizontal and vertical-axis turbines with a total capacity of 1.7 MW, while Zhejiang University has deployed turbines ranging from 60 kW to 600 kW.

Another unique approach was taken by Pulse Tidal, which developed an oscillating hydrofoil—a device with blades that move up and down—though the company was liquidated in 2014.

Industry Evolution and Corporate Shifts

The tidal industry has seen significant consolidation. Tidal Generation Ltd (TGL) passed through the ownership of Rolls-Royce, Alstom, and General Electric before its assets were acquired by Sabella in 2021. Sabella itself developed the 1 MW D10 turbine, which is now operated by Inyanga Marine Energy.

Proteus Marine Renewables, formed via a management buyout from SIMEC Atlantis Energy, continues to support the MeyGen farm and is expanding into Japan with the 1.1 MW AR1100 turbine.

Looking up at the Sabella D10 turbine from ground level. At the top of the image are 6 large blades around a bulbous hub, all painted bright blue. The cylindrical nacelle behind is supported on a pile with tubular steel bracing forming a tripod. The Nacelle and foundation are painted bright blue. — Sabella D10 turbine

SME PLAT-I 6.4 horizontal, in-stream, floating tidal energy generator at Grand Passage site in Nova Scotia, Canada.

A workboat with a large crane is lowering a tidal turbine mounted on a triangular steel frame into the sea. — Tidal Energy Ltd - DeltaStream device installation in Ramsey Sound, Pembrokeshire in 2015

The faded yellow nacelle of a tidal turbine, with three stubby blue blades at the left. Below and in front is a car, portacabin and fencing typical of industrial settings — The 500 kW TGL DeepGen III tidal stream turbine at Hatston Pier, Orkney

A faded yellow nacelle of a tidal turbine, with three stubby blades at the left, the top one with traces of red paint. Two people stand below the blades, a third person is in a cherrypicker lift to the right. A metal frame with steps lead up to the rear of the nacelle on the right of the image. — The 1 MW TGL DeepGen IV tidal stream turbine at Hatston Pier, Orkney

The large cylidrical white nacelle of the 1MW Voith HyTide tidal stream generator, with 3 stubby blue blades part way along. It sitting on a pier, two cars below dwarfed by the scale of the turbine. Behind is a large heavy-lift ship used for the installation. — The 1MW Voith HyTide tidal stream generator sitting on Hatston Pier, Orkney

Summary of Key Tidal Technologies

Company	Device/Project	Capacity	Type	Key Status/Achievement
SIMEC Atlantis	MeyGen (AR1500)	1.5 MW	Seabed-mounted	World's largest array
Orbital Marine Power	Orbital O2	2 MW	Floating	Twin-rotor design
Minesto	Dragon 4	100 kW	Tidal Kite	Deployed in Faroe Islands
Andritz Hydro	Mk1	1.5 MW	Seabed-mounted	Over 80GWh generated
Sustainable Marine	PLAT-I 6.4	420 kW	Floating	First floating power to Canada grid
Proteus Marine	AR1100	1.1 MW	Seabed-mounted	Deployed in Japan (2025)

Frequently Asked Questions

What is the difference between a horizontal-axis and vertical-axis tidal turbine?

A horizontal-axis turbine has a rotor shaft parallel to the flow of the water (like a traditional windmill), whereas a vertical-axis turbine has a shaft perpendicular to the flow, allowing it to capture water from any direction without needing a yaw mechanism.

Why are floating tidal turbines becoming more popular?

Floating turbines, such as those from Orbital Marine Power, are generally easier to install and maintain because they can be towed to shore for repairs, avoiding the need for expensive heavy-lift vessels required for seabed-mounted units.

What is a tidal kite?

A tidal kite, developed by companies like Minesto, is a tethered underwater wing that "flies" in a figure-eight pattern. This motion increases the relative speed of the water passing through the turbine, allowing for power generation in lower-velocity currents.

Which project is currently the largest in the world?

The MeyGen project in the Pentland Firth, developed by SIMEC Atlantis Energy (now Ampeak Energy), is the largest tidal-stream array worldwide, currently operating with four 1.5 MW turbines.

What happened to the OpenHydro and BigMoon Power projects?

OpenHydro ceased trading in 2018 after being acquired by Naval Energies. BigMoon Power (later Occurrent Power) filed for insolvency in September 2024 after failing to deploy its planned turbines in the Bay of Fundy.