Marine energy
Extracting energy from tides, currents and waves. The great attraction: tides are perfectly predictable, years ahead, unlike sun and wind. But most marine technologies remain pre-commercial, because the sea is a brutal place to build and maintain machines.
The main families
Tidal range & tidal stream
Two distinct families: tidal range (barrages) exploits the head difference behind an estuary dam; tidal stream places underwater turbines in fast currents. Tidal range is the only truly mature marine technology; tidal stream is just leaving the demonstration stage.
Wave energy
Wave energy converters (WEC) capture the motion of the swell. No dominant design has emerged: oscillating water columns, heaving floating bodies, articulated attenuators and shoreline devices still compete. The sector remains largely pre-commercial, at prototype and demonstrator scale.
Gradients & OTEC
Still-experimental concepts: ocean thermal energy conversion (OTEC) exploits the temperature gap between warm surface and cold deep water in the tropics; salinity gradient (osmotic) power taps the salt difference between fresh and sea water. Neither has reached commercial stage.
Key challenges
- Extreme marine environment — salt corrosion, biofouling (organisms colonizing structures), storms and violent swell, fatigue loads: the sea destroys machines, and offshore maintenance is costly, weather-dependent and limited by intervention windows.
- Technology maturity — most technologies remain pre-commercial: no dominant design has emerged for wave energy, and only tidal range is truly mature. Tidal stream is just reaching its first arrays at scale.
- Subsea connection & grid — dynamic and subsea cables, wet-mate connectors, offshore substations, grid-code integration: getting the electricity out of the water and onshore is a major share of cost and risk.
- Predictability — tides are calculable years ahead from astronomy: a real and unique advantage over wind and PV, whose output stays fundamentally random. A tidal plant delivers a power curve known in advance.
See also
Marine-energy-specific standards
- IEC TS 62600 — Technical specification series dedicated to marine energy converters — wave, tidal and current: terminology, performance, mooring, resource measurement.
- Offshore & subsea — Marine devices borrow heavily from offshore and subsea engineering practice: structures, moorings, dynamic cables, maintenance ROVs, cathodic protection.
Related standard pages on IndustryHub
Major players
Tidal stream
Orbital Marine Power, Proteus Marine (ex-SIMEC Atlantis), Nova Innovation.
Wave energy
CorPower Ocean, Mocean Energy, Eco Wave Power.
Tidal range
EDF — La Rance, and equivalents.
Projects & arrays
SAE Renewables, offshore developers.
Landmark facts
| Fact | Year | Place | Lesson |
|---|---|---|---|
| "La Rance" — first tidal power station | 1966 | France | The world's first tidal power station, and for decades the largest. Still operating, it proves tidal range at industrial scale — the only truly mature marine technology. |
| "MeyGen" — tidal-stream array | 2016- | Scotland | One of the largest tidal-stream arrays in the world, a milestone toward commercial underwater turbines in strong currents. |