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

Why fixed costs make small schemes dearer per kilowatt

Source page: https://www.materialinsights.org/energy/e_small_hydro/resources/

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 hydro^[13](https://world-nuclear.org/information-library/energy-and-the-environment/mineral-requirements-for-electricity-generation.aspx) | 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 projects^[2](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2012/RE_Technologies_Cost_Analysis-HYDROPOWER.pdf) | 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 outflow^[2](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2012/RE_Technologies_Cost_Analysis-HYDROPOWER.pdf) | 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 higher^[15](https://Sswm.info/sites/default/files/reference_attachments/PRACTICAL%20ACTION%204000%20Hydraulic%20Ram%20Pumps.pdf) | 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 globally^[10](https://www.ilo.org/sites/default/files/2026-01/IRENA_SOC_RE_and_jobs_2026.pdf) | 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 hydropower^[10](https://www.ilo.org/sites/default/files/2026-01/IRENA_SOC_RE_and_jobs_2026.pdf) | As above | The only national split by type in the IRENA review. |
| **Operation and maintenance** | 1-6% of investment per year for small hydro^[2](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2012/RE_Technologies_Cost_Analysis-HYDROPOWER.pdf) | 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 labour^[2](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2012/RE_Technologies_Cost_Analysis-HYDROPOWER.pdf) | Local builders for weirs and channels, with specialist installers | Civil works are simple enough to be built locally. |

#### Sources

1. [Renewable Energy Technologies: Cost Analysis Series, Hydropower (Volume 1, Issue 3/5)](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2012/RE_Technologies_Cost_Analysis-HYDROPOWER.pdf) IRENA, 2012
2. [Renewable Energy and Jobs: Annual Review 2025 (Table 1, 2024 employment)](https://www.ilo.org/sites/default/files/2026-01/IRENA_SOC_RE_and_jobs_2026.pdf) IRENA and International Labour Organization, 2026
3. [Mineral Requirements for Electricity Generation (citing IEA 2021 and US DOE Quadrennial Technology Review 2015)](https://world-nuclear.org/information-library/energy-and-the-environment/mineral-requirements-for-electricity-generation.aspx) World Nuclear Association, 2024
4. [Hydraulic ram pumps (technical brief)](https://Sswm.info/sites/default/files/reference_attachments/PRACTICAL%20ACTION%204000%20Hydraulic%20Ram%20Pumps.pdf) Practical Action

## Other sections

- [Summary](https://www.materialinsights.org/energy/e_small_hydro/index.md)
- [Overview](https://www.materialinsights.org/energy/e_small_hydro/overview/index.md)
- [Correlation](https://www.materialinsights.org/energy/e_small_hydro/correlation/index.md)
- [Efficiency](https://www.materialinsights.org/energy/e_small_hydro/efficiency/index.md)
- [Techniques](https://www.materialinsights.org/energy/e_small_hydro/techniques/index.md)
- [Impact on the biosphere](https://www.materialinsights.org/energy/e_small_hydro/biosphere/index.md)
- [Relationships](https://www.materialinsights.org/energy/e_small_hydro/links/index.md)