--- title: "Conventional sources and features of a station" subject: "Power System Analysis I" chapter: 1 key: "semester_4/power_system_analysis_i:conventional-sources-features" source: https://www.bctengineer.com/q/semester_4/power_system_analysis_i/conventional-sources-features site: BCT Engineering --- # Conventional sources and features of a station Power System Analysis I · Chapter 1: General Background - Asked in: 2073 Magh, 5 marks - Video: [Energy Resources - Conventional and Non-Conventional](https://www.youtube.com/watch?v=Zgp86PVXXuQ) — Amit Sengupta - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_4/power_system_analysis_i/conventional-sources-features - Whole chapter: https://www.bctengineer.com/md/semester_4/power_system_analysis_i/chapter-1 ## Question What are conventional sources of energy? List out some features of one of the power generating stations using conventional energy sources. ## Short answer Conventional sources are fossil fuels, nuclear fuel and large hydropower. A coal-fired steam station burns coal to make steam for a turbine, has low initial cost but high running cost, 30-40% efficiency, pollution, and is used as base load. ## Answer **Conventional sources of energy** are the long-established sources that have been used on a large scale for electricity generation, mainly fossil fuels (coal, oil, natural gas), nuclear fuel and (in many textbooks) large hydropower. Fossil and nuclear fuels are finite and are being used up faster than nature can replace them. #### Features of a steam (coal-fired) thermal power station ```text Coal -> [Boiler] -> steam -> [Turbine]--[Alt]-> Grid ^ | | [Condenser] [Feed pump] <-- water -----+ ``` 1. **Principle:** Coal is burned in a boiler; heat converts water into high-pressure superheated steam, which drives a steam turbine coupled to an alternator (Rankine cycle). 2. **Location:** Near coal mines or a railway line and a large water source for the condenser and cooling. 3. **Low initial cost** per kW compared with hydro, and shorter construction time. 4. **High running cost:** Continuous purchase and transport of coal. 5. **Low overall efficiency:** About 30–40 %, because much heat is rejected in the condenser. 6. **Pollution:** Emits CO₂, SO₂, NOx, fly ash; needs ash handling, electrostatic precipitators and tall chimneys. 7. **Large space** for coal storage and ash disposal. 8. **Slow start:** Takes hours to start and load up; best used as a **base-load** plant. 9. **Large unit sizes** (200–1000 MW) possible; output is steady and independent of weather. 10. **Water requirement** is large for the condenser and boiler make-up. Nepal has no such coal plants; its conventional backup is small diesel plants, while hydropower supplies the grid. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. Which set best matches conventional energy sources? A. Solar, wind and tidal B. Biogas and geothermal only C. Fossil fuels, nuclear fuel and large hydro D. Fuel cells and OTEC Answer: C. Conventional sources are the long-established large-scale ones: coal, oil, gas, nuclear and often large hydro. (Key point: Meaning of conventional sources) 2. In a coal-fired station, what drives the alternator? A. A steam turbine run on high-pressure superheated steam from the boiler (Rankine cycle) B. A water turbine fed by a penstock C. A gas turbine fed directly by coal D. A diesel engine Answer: A. Burning coal in the boiler raises steam which expands in the turbine coupled to the alternator. (Key point: Working principle of steam station) 3. Why is overall efficiency of a steam station only about 30-40 %? A. Boiler leakage B. Alternator losses are large C. Coal has no energy D. Much heat is rejected in the condenser Answer: D. Most of the fuel heat is carried away by the condenser cooling water. (Key point: Efficiency of thermal station) 4. Why is a thermal plant best used as a base-load plant? A. It starts in seconds B. Its output depends on weather C. It starts and loads up slowly (takes hours) D. It has no running cost Answer: C. Slow start makes it unsuitable for quick peak response, so it runs steadily on base load. 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