Offshore wind: Resources and labour
Why each sea turbine swallows so much steel and labour
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.Offshore wind needs more steel and cable per MW than onshore wind, because foundations stand in water and power must travel along subsea cables. Most of its labour is in manufacturing.
Natural resources
| Resource | How much | Why it is needed |
|---|---|---|
| Steel and cast iron | About 540 t per MW (calculated from 272,274 t for a 504 MW reference farm of 63 turbines on steel monopiles)9 | Monopiles and towers must resist wind, waves and currents; the larger the turbine and the deeper the water, the more steel. |
| Critical minerals in total | About 15.5 t per MW (IEA estimate), against about 10 t per MW onshore10 | Long array and export cables use large amounts of copper, and offshore turbines more often use direct-drive generators with rare-earth magnets. |
| Rare-earth magnet material (NdFeB) | About 0.6 t per MW (calculated from 302 t for the 504 MW reference farm)9 | Direct-drive permanent-magnet generators avoid a gearbox, which is attractive offshore where repairs are costly. |
| Glass fibre | About 13 t per MW (calculated from 6,615 t for 504 MW)9 | Blades over 80 m long must be light and stiff. |
Labour
| Phase | How much | Skills | Why it is needed |
|---|---|---|---|
| Manufacturing and procurement | About 1.26 million person-days per 500 MW (59% of total), about 2,500 per MW (calculated)9 | Steel fabricators, welders, composite and electrical engineers | Very large components (nacelles, blades, monopiles, cables) are made in specialised port-side factories. |
| Construction (installation and grid connection) | 237,249 person-days per 500 MW (11%), about 470 per MW (calculated)9 | Marine crews, crane and vessel operators, divers, cable specialists | Installation is done from specialised vessels in weather windows. |
| Operation and maintenance | 25,073 person-days per 500 MW per year, about 50 per MW per year (calculated); 24% of lifetime labour over 25 years9 | Offshore technicians, vessel and helicopter crews, engineers | Turbines in harsh marine conditions need regular access by boat or helicopter. |
| Decommissioning | 97,453 person-days per 500 MW (5%), about 190 per MW (calculated)9 | Marine engineering and recycling | Structures must be removed or made safe at end of life. |
| All phases, global total | About 1.9 million wind jobs worldwide in 2024, onshore and offshore combined11 | As above | IRENA does not split wind jobs into onshore and offshore. |
IRENA's reference farm needs about 2.1 million person-days in all, roughly 4,200 per MW (calculated), compared with about 2,900 per MW for its 50 MW onshore reference (calculated), mainly because of heavier manufacturing, especially of foundations.
Sources
- Renewable Energy Benefits: Leveraging Local Capacity for Offshore Wind (500 MW wind farm) IRENA, 2018
- Mineral Requirements for Electricity Generation (citing IEA 2021 and US DOE Quadrennial Technology Review 2015) World Nuclear Association, 2024
- Renewable Energy and Jobs: Annual Review 2025 (Table 1, 2024 employment) IRENA and International Labour Organization, 2026