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Development phases; pre-feasibility factors

Short answer

Phases: reconnaissance, pre-feasibility, feasibility, detailed design, construction, operation. Pre-feasibility studies examine topography, hydrology, geology, layout alternatives, access, transmission, cost, environment, and social factors. Feasibility adds detailed investigations, design optimisation, financial analysis, and environmental assessment.

Mention different phases of the hydropower development cycle. What factors do you consider in the pre-feasibility and feasibility study of hydropower projects?

Phases of the hydropower development cycle

Reconnaissance, pre-feasibility, feasibility, detailed design and tender, construction and commissioning, operation and maintenance.

Factors in the pre-feasibility study

  • Topography: map and survey of headworks, waterway and powerhouse; choose the layout alternatives.
  • Hydrology: mean flow, flow duration curve, floods and sediment from available data and short-term gauging.
  • Geology: surface mapping and geophysics for dam, tunnel and powerhouse sites; landslide and fault risk.
  • Alternatives: capacity, head, and type of scheme (RoR, PRoR, storage); choose the best one.
  • Access and transmission: road and line routes, distance to the grid and market.
  • Cost and economics: rough cost (±20-25%), energy and B/C, IRR.
  • Environment and society: screening of protected areas, land, settlement, and fish.

Additional factors in the feasibility study

  • Accurate and detailed survey, drilling, tests, and material surveys.
  • Long-term hydrology, 100- and 1000-year floods, sediment and GLOF.
  • Optimisation of the installed capacity, final layout and equipment selection.
  • Detailed quantity and cost estimate (±10-15%) and construction schedule.
  • Financial analysis (NPV, IRR, B/C, sensitivity), financing plan, and the power market (PPA).
  • IEE/EIA, resettlement, risk and legal clearances.

✓ Answer checked by Claude Opus 5.5 (high effort)

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