- 2075 Bhadra · 4 marks
Pre-feasibility versus feasibility studies
Short answer
Pre-feasibility screening alternatives to select the best layout with approximate costs (±25–30%). Feasibility study detailly confirms the chosenscheme 's technical, economic, and environmental viability with refined costs (±10–15%) to secure financing.
Explain the differences between Pre-feasibility and Feasibility studies in hydropower projects.
Pre-feasibility study is a preliminary study that compares alternative layouts of a hydropower site and selects the most promising one. Feasibility study is a detailed study of the selected scheme to prove that it is technically, economically, financially and environmentally viable and ready for financing.
| Point | Pre-feasibility study | Feasibility study |
|---|---|---|
| Purpose | Screen alternatives and choose the best | Confirm viability of the chosen scheme |
| Stage | After reconnaissance/desk study | After pre-feasibility, before detailed design |
| Data | Existing maps (1:50,000), short or regional hydrology | Detailed survey (1:1000–1:5000), site flow measurement |
| Investigations | Surface geological mapping, few tests | Drilling, test pits, seismic survey, material tests |
| Design | Conceptual layouts, rough sizes | Optimised layout, preliminary design of all structures |
| Cost estimate accuracy | About ±25–30% | About ±10–15% |
| Environment | Initial screening of impacts | Full IEE/EIA |
| Output | Recommended alternative, go/no-go | Bankable report: B/C, IRR, financing plan |
| Cost and time | Low, a few months | High, one to two years |
In short, the pre-feasibility study answers "which option is best?", and the feasibility study answers "is this option worth building, and how?".
✓ Answer checked by Claude Opus 5.5 (high effort)
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