Run-of-river and small hydro: Resources and labour

Why fixed costs make small schemes dearer per kilowatt

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.

Small schemes need a weir or intake, a pipe or channel, a turbine and a generator. Materials are modest in total, but per kW they cost more than large plants because fixed elements do not shrink in proportion.

Natural resources

Resource	How much	Why it is needed
Concrete and steel	For hydropower in general, about 14,000 t of concrete and 67 t of steel per TWh (US DOE); not reported separately for small hydro¹³	A weir or intake must divert water reliably through floods; steel penstocks carry water under pressure.
Electro-mechanical equipment	18-50% of total cost for small projects²	Turbines, generators and controls are a large share when civil works are small.
Water	Not consumed, but diverted out of the river between intake and outflow²	Head is created by carrying water along a gentler slope than the river, then dropping it to the powerhouse.
Drive water (hydraulic rams)	Most of the inflow is spilled to lift a smaller flow higher¹⁵	Energy from a large flow falling a short height is used to lift a small flow a greater height.

Labour

Phase	How much	Skills	Why it is needed
All phases, global total	2.26 million hydropower jobs in 2024; small and large not split globally¹⁰	Civil works, mechanical and electrical installation, local operators	IRENA reports hydropower as one category.
United States split	58,089 jobs in traditional hydropower and 12,111 in low-impact hydropower¹⁰	As above	The only national split by type in the IRENA review.
Operation and maintenance	1-6% of investment per year for small hydro²	Local operators to clear intakes of debris and maintain turbines	Intakes clog with leaves and sediment, and small schemes cannot spread fixed staff costs.
Construction	Lower cost in developing countries through use of local labour²	Local builders for weirs and channels, with specialist installers	Civil works are simple enough to be built locally.

Sources

Renewable Energy Technologies: Cost Analysis Series, Hydropower (Volume 1, Issue 3/5) IRENA, 2012
Renewable Energy and Jobs: Annual Review 2025 (Table 1, 2024 employment) IRENA and International Labour Organization, 2026
Mineral Requirements for Electricity Generation (citing IEA 2021 and US DOE Quadrennial Technology Review 2015) World Nuclear Association, 2024
Hydraulic ram pumps (technical brief) Practical Action