--- title: "Development phases; pre-feasibility factors" subject: "Hydropower Engineering" chapter: 2 key: "semester_7/hydropower_engineering:dev-phases-prefeasibility-factors" source: https://www.bctengineer.com/q/semester_7/hydropower_engineering/dev-phases-prefeasibility-factors site: BCT Engineering --- # Development phases; pre-feasibility factors Hydropower Engineering · Chapter 2: Planning of Hydropower Projects - Asked in: 2080 Bhadra, 2+2+2 marks - Video: [What are the Stage of Hydropower Development #water #energy #generated #powerhouse #dam #electricity](https://www.youtube.com/watch?v=QAR-x4D_0Gk) — Hydropower - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_7/hydropower_engineering/dev-phases-prefeasibility-factors - Whole chapter: https://www.bctengineer.com/md/semester_7/hydropower_engineering/chapter-2 ## Question Mention different phases of the hydropower development cycle. What factors do you consider in the pre-feasibility and feasibility study of hydropower projects? ## 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. ## Answer #### 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. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What cost accuracy is expected from pre-feasibility and feasibility studies respectively? A. ±5% and ±1% B. ±10-15% and ±20-25% C. ±20-25% and ±10-15% D. ±50% and ±30% Answer: C. Accuracy improves from about ±20-25% in pre-feasibility to ±10-15% in feasibility. (Key point: Cost accuracy) 2. Which hydrological work is typical at pre-feasibility level? A. Mean flow, flow duration curve, floods and sediment from available data and short-term gauging B. 1000-year flood and GLOF analysis with long records only C. Hydraulic model tests D. No hydrology is done Answer: A. Pre-feasibility uses available data and short gauging; long-term series and extreme floods are added at feasibility. (Key point: Pre-feasibility hydrology) 3. What is a key aim regarding alternatives in pre-feasibility? A. Fix the final turbine rating B. Compare capacity, head and scheme type (RoR, PRoR, storage) and choose the best C. Sign the PPA D. Prepare tender drawings Answer: B. Several alternatives are compared and the best one selected for feasibility study. (Key point: Pre-feasibility alternatives) 4. Which is an additional factor of the feasibility study, not of pre-feasibility? A. Screening of protected areas B. Rough B/C estimate C. Financial analysis (NPV, IRR, sensitivity), financing plan and PPA D. Choosing layout alternatives Answer: C. Feasibility adds detailed financial analysis, financing and market arrangements. (Key point: Feasibility additions) ## Related in Hydropower Engineering - [Stages of hydropower development cycle](https://www.bctengineer.com/question.md?key=semester_7%2Fhydropower_engineering%3Adev-cycle-stages) — Hydropower Engineering, chapter 2 - [Pre-feasibility site-specific investigations](https://www.bctengineer.com/question.md?key=semester_7%2Fhydropower_engineering%3Aprefeasibility-site-investigations) — Hydropower Engineering, chapter 2 - [Studies in reconnaissance, pre-feasibility, feasibility](https://www.bctengineer.com/question.md?key=semester_7%2Fhydropower_engineering%3Arecon-prefeas-feas-studies) — Hydropower Engineering, chapter 2, asked 3× - [Pre-feasibility vs feasibility; site investigations](https://www.bctengineer.com/question.md?key=semester_7%2Fhydropower_engineering%3Aprefeasibility-vs-feasibility-investigations) — Hydropower Engineering, chapter 2 - [Steps of a feasibility study (team leader)](https://www.bctengineer.com/question.md?key=semester_7%2Fhydropower_engineering%3Afeasibility-study-steps-consultant) — Hydropower Engineering, chapter 2 - [Development cycle; RoR layout with headrace canal](https://www.bctengineer.com/question.md?key=semester_7%2Fhydropower_engineering%3Adev-cycle-ror-layout-headrace-canal) — Hydropower Engineering, chapter 2 ## Related in other subjects - [Project development life cycle phases](https://www.bctengineer.com/question.md?key=semester_7%2Fict_project_management%3Aproject-development-life-cycle) — ICT Project Management, chapter 1 - [Pre-feasibility versus feasibility studies](https://www.bctengineer.com/question.md?key=semester_6%2Fhydro_power%3Aprefeasibility-vs-feasibility) — Hydro Power, chapter 3 - [PDLC and feasibility study](https://www.bctengineer.com/question.md?key=semester_7%2Fict_project_management%3Apdlc-feasibility-study) — ICT Project Management, chapter 1 - [Stages of hydropower project study](https://www.bctengineer.com/question.md?key=semester_6%2Fhydro_power%3Ahydropower-study-stages) — Hydro Power, chapter 3, asked 3×