Hydropower dams: Resources and labour

Mountains of concrete, little steel, and whole valleys flooded

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.

Dams are dominated by concrete and earthworks and by the land the reservoir floods. They need far less steel and copper per unit of electricity than wind, because they run for many decades.

Natural resources

Resource	How much	Why it is needed
Concrete	About 14,000 t per TWh generated (US DOE), against 8,000 t per TWh for wind⁸	The dam must resist the full pressure of the water behind it, which rises with depth; mass and strength keep it stable.
Steel	About 67 t per TWh (US DOE), against 1,920 t per TWh for wind⁸	Penstocks, gates, turbines and generators are steel, but these are small relative to the lifetime output.
Copper	About 1 t per TWh (US DOE); critical mineral needs are comparatively low (IEA)⁸	Generator windings and transformers; few machines produce a lot of power.
Land flooded by the reservoir	0.027 m2 of land occupied for a year per kWh, average of the Norwegian plants studied (0.007 after adjusting for uncertainty); 0.004 in the Ecoinvent database for Switzerland¹⁰	Storing energy as raised water needs a large volume, and so a large area, of water behind the dam.
Site-specific civil works (as a cost proxy)	About three-quarters of total investment³	Geology, valley shape and access decide how much excavation, tunnelling and concrete a site needs.

Labour

Phase	How much	Skills	Why it is needed
All phases, global total	About 2.26 million hydropower jobs in 2024, about 30% in China and 22% in India⁹	Civil engineers, geologists, tunnellers, concrete and steel workers, electrical and mechanical technicians	Construction is a large civil engineering project lasting years; operation needs fewer but skilled staff.
Per unit of capacity	About 1.8 jobs per MW of conventional capacity (calculated from 2.26 million jobs and about 1,268 GW), counting construction of new plants as well as operation⁹⁶	As above	Gives a rough scale only; IRENA does not publish hydropower jobs by phase globally.
Operation and maintenance	O&M costs about 2-2.5% of investment per year for large plants³	Plant operators, turbine and generator maintenance, dam safety engineers	Turbines need periodic overhaul and dams constant monitoring over a life of 40 to 80 years or more.
Construction	Projects in developing countries often use local labour, lowering cost³	Large semi-skilled workforce plus specialist engineers	Excavation and concrete placement are labour intensive.

Sources

Renewable Energy Technologies: Cost Analysis Series, Hydropower (Volume 1, Issue 3/5) IRENA, 2012
Year of the water battery: global pumped storage capacity surpasses 200 GW (2026 World Hydropower Outlook) International Hydropower Association, 2026
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
Land under water: estimating hydropower's land use impacts (on Dorber, May and Verones, Environmental Science and Technology 2018) NASA Landsat Science, 2018