Tidal and ocean-current power: Resources and labour

Concrete walls, giant bulb turbines and very fast water

What this tab covers The natural resources (land, water, materials, fuel or feedstock) and the labour needed to capture this energy, per unit, with the reason each is needed.

Barrages are civil-engineering projects dominated by concrete and steel; tidal stream turbines need steel, composites, moorings or foundations and subsea cable.

Natural resources

Resource	How much	Why it is needed
Concrete and steel (barrage)	La Rance: 750 m barrage with a 332.5 m power section⁴	The structure must hold back a tidal head of several metres and withstand storms for a century.
Enclosed water area	La Rance basin 22 km2 (184 million m3) for 240 MW⁴	Energy depends on the volume of water stored and released, so large basins are needed.
Turbines and generators	La Rance: 24 bulb turbines, 5.35 m diameter, 10 MW each⁴	Low-head, high-flow water needs large-diameter machines.
Foundations (tidal stream)	Concrete and steel gravity bases, monopiles or floating platforms; tonnage not published³	Turbines must resist the large thrust of dense, fast-moving water.
Fast-flowing channel	Useful currents above about 1.5-2 m/s³	Power rises with the cube of current speed, so only fast channels are worth using.

Labour

Phase	How much	Skills	Why it is needed
Manufacturing	Not quantified³	Turbine, composite blade and generator manufacture	Similar supply chain to wind and hydro turbines.
Construction	La Rance took from 1961 to 1967, with the estuary closed from 1963⁴	Civil engineering, cofferdams, marine works; for tidal stream, heavy-lift vessels and divers	Barrages are built in the dry behind temporary dams.
Operation	Not quantified³	Hydro plant operators; marine technicians for tidal stream	Submerged turbines must be lifted out for maintenance.
Decommissioning	Europe has decommissioned 19.3 MW of tidal stream devices since 2010⁵	Marine salvage	Many devices were short-term demonstrators.

Sources

Tidal Energy: Technology Brief IRENA, 2014
La Rance Tidal Barrage (Annex IV site page) PNNL Tethys, 2024
Ocean Energy: Key Trends and Statistics 2024 Ocean Energy Europe (copy hosted by PNNL Tethys), 2025