--- title: "Power system expansion planning for a utility" subject: "Power Plant Design" chapter: 2 key: "semester_8/power_plant_design:expansion-planning-national-utility" source: https://www.bctengineer.com/q/semester_8/power_plant_design/expansion-planning-national-utility site: BCT Engineering --- # Power system expansion planning for a utility Power Plant Design · Chapter 2: Integrated System Planning in Design Approach - Asked in: 2080 Chaitra, 6 marks - Video: [EE Power System Planning Part 1 by Dr Prateek Singhal](https://www.youtube.com/watch?v=8nmJ9mEiYog) — RTUKOTA econtents - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_8/power_plant_design/expansion-planning-national-utility - Whole chapter: https://www.bctengineer.com/md/semester_8/power_plant_design/chapter-2 ## Question What is power system expansion planning? Discuss its applicability in context of a national electric utility organization. ## Short answer Power system expansion planning decides the least-cost generation, transmission, and distribution additions over 10–25 years to meet forecast load reliably. For a national utility, it aligns capacity with rising demand, selects a seasonal mix, plans transmission corridors, secures financing, and supports policy. ## Answer **Power system expansion planning** is the long-term (10–25 years) process of deciding the least-cost additions of generation, transmission and distribution facilities, with their type, size, location and timing, to meet the forecast load with a required level of reliability. #### Components 1. **Load forecasting:** peak demand and energy by year and region. 2. **Generation expansion planning:** which plants to build and when. 3. **Transmission expansion planning:** new lines and substations to carry power. 4. **Distribution planning:** feeders and substations to supply consumers. 5. **Financial and environmental analysis.** #### Applicability for a national utility (e.g. NEA) - **Meeting future demand:** A national utility must ensure that capacity grows ahead of demand; NEA's load forecast shows demand rising quickly due to EVs, cooking and industry. - **Least-cost mix:** It chooses the right combination of ROR, storage, pumped storage, solar and import so that both wet-season and dry-season needs are met. Nepal's heavy ROR share causes wet-season surplus and winter deficit; expansion planning recommends storage projects to fix it. - **Transmission backbone:** It identifies corridors (e.g. 400 kV east–west and north–south lines) and cross-border links for export. - **Reliability target:** It sets reserve margin and N-1 security so that load shedding is avoided. - **Investment and tariff:** It gives the basis for borrowing from donors (ADB, World Bank), for PPAs with IPPs and for tariff approval by the regulator. - **Coordination:** It aligns national policy (Energy Roadmap, about 28,500 MW by 2035), private sector and regional trade. - **Timing:** Hydro projects take 5–10 years to build, so decisions must be taken early. Without expansion planning a utility either faces shortage and load shedding (as Nepal did before 2016) or idle capacity and energy spill. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. Power system expansion planning is A. a daily dispatch schedule B. long-term (10-25 years) least-cost planning of generation, transmission and distribution additions for forecast load C. a short-circuit study D. a tariff table Answer: B. It decides type, size, location and timing of additions with a reliability level. (Key point: Definition) 2. Which is NOT a component of expansion planning? A. Load forecasting B. Generation expansion planning C. Distribution planning D. Relay setting of a single feeder Answer: D. Components are load forecast, generation, transmission, distribution and financial/environmental analysis. (Key point: Components) 3. Why does expansion planning recommend storage projects for Nepal? A. ROR-heavy system has wet-season surplus and winter deficit B. Storage is cheaper than ROR C. Nepal has no rivers D. Storage removes need for transmission Answer: A. Storage shifts water energy from wet to dry season and balances the ROR dominance. (Key point: Least-cost mix for Nepal) 4. Why must expansion decisions be taken early? A. Demand never grows B. Hydro takes 5-10 years to build C. Tariff is fixed D. Lines are not needed Answer: B. Long lead times mean capacity must be started well ahead of demand, otherwise shortage occurs. (Key point: Timing) ## Related in Power Plant Design - [Transmission expansion planning and applicability](https://www.bctengineer.com/question.md?key=semester_8%2Fpower_plant_design%3Atransmission-expansion-applicability) — Power Plant Design, chapter 2 - [Factors affecting system expansion planning](https://www.bctengineer.com/question.md?key=semester_8%2Fpower_plant_design%3Asystem-expansion-factors) — Power Plant Design, chapter 2 - [Power system planning and grid integration](https://www.bctengineer.com/question.md?key=semester_8%2Fpower_plant_design%3Aplanning-deregulated-grid-integration) — Power Plant Design, chapter 2 - [Reserve planning and utility interconnection](https://www.bctengineer.com/question.md?key=semester_8%2Fpower_plant_design%3Areserve-planning-interconnection) — Power Plant Design, chapter 2 - [Generation expansion planning procedure](https://www.bctengineer.com/question.md?key=semester_8%2Fpower_plant_design%3Ageneration-expansion-procedure) — Power Plant Design, chapter 2, asked 3× - [Transmission expansion planning in deregulated market](https://www.bctengineer.com/question.md?key=semester_8%2Fpower_plant_design%3Atransmission-planning-deregulated) — Power Plant Design, chapter 2 ## Related in other subjects - [Types of electric wiring system compared](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Awiring-systems-comparison) — Industrial Power Distribution and Illumination, chapter 5 - [Microprocessor based system and bus organization](https://www.bctengineer.com/question.md?key=semester_4%2Fmicroprocessor%3Amp-based-system-bus-organization) — Microprocessor, chapter 1, asked 5× - [Organization as an open system](https://www.bctengineer.com/question.md?key=semester_7%2Forganization_and_management%3Aorg-open-system) — Organization and Management, chapter 1 - [Infinite bus and national grid as infinite bus](https://www.bctengineer.com/question.md?key=semester_4%2Fpower_system_analysis_i%3Ainfinite-bus-national-grid) — Power System Analysis I, chapter 1