Small Hydropower Design

Every small hydro lay-out presents a value engineering challenge specific to the project site. Locating, conceptually designing and selecting a portfolio of profitable small hydro projects for subsequent feasibility study and development requires a professional and systematic approached coupled with an experienced understanding of the technology and the commercial drivers. A cost effective small-scale hydroelectric facility requires the combination, within design, of a sizable flow of water and a suitable height of fall of water, called head, whilst maximising the investment return rate. Run-of-river small hydro often involves diversion of the flow in a river (as in Figure 1). Diversion is often required to take advantage of the drop in elevation that occurs over a distance in the river. Diversion projects reduce the flow in the river between the intake and the powerhouse. A diversion weir or small dam is usually required to divert the flow into the intake.

Figure 1: A small ROR hydro facility

hydro site

A ROR scheme may consists of the following major components;

  • Diversion Structure, weir or intake
  • Power channel or canal
  • Penstock (pipeline)
  • Sand removal structure, trash rack and screens
  • Forbay tank or Charge Chamber
  • Powerhouse
  • Tailrace structure
  • Turbine, generator and electrical switchgear
  • Transformer and electrical transmission

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