---
title: "Energy saving opportunities in industrial plant"
subject: "Industrial Power Distribution and Illumination"
chapter: 10
key: "semester_6/industrial_power_distribution_and_illumination:energy-saving-opportunities"
source: https://www.bctengineer.com/q/semester_6/industrial_power_distribution_and_illumination/energy-saving-opportunities
site: BCT Engineering
---

# Energy saving opportunities in industrial plant

Industrial Power Distribution and Illumination · Chapter 10: Electrical Energy Audit in Industry

- Asked in: 2073 Magh, 4 marks; 2068 Jestha (old course), 8 marks (asked 2 times)
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/industrial_power_distribution_and_illumination/energy-saving-opportunities
- Whole chapter: https://www.bctengineer.com/md/semester_6/industrial_power_distribution_and_illumination/chapter-10

## Question

State the energy saving opportunity in an industrial plant.

## Answer

Energy saving opportunities (energy conservation measures) are the changes in equipment, operation and maintenance that reduce energy use without reducing output.

#### 1. Electrical supply system
- Improve **power factor** with capacitor banks (APFC) – reduces kVA demand, losses and penalties.
- Run transformers near optimum load; switch off lightly loaded transformers.
- Reduce **maximum demand** through load management and shifting to off-peak hours.
- Balance phase loads; correct voltage level; reduce harmonics with filters.
- Use proper cable sizes to reduce I²R losses.

#### 2. Motors and drives
- Replace old or rewound motors with **energy-efficient (IE3/IE4) motors**.
- Avoid oversized, under-loaded motors; use star-delta switching for lightly loaded motors.
- Use **variable frequency drives (VFDs)** on fans, pumps and compressors instead of dampers/throttle valves.
- Use efficient belts (flat/cogged), proper alignment and lubrication.

#### 3. Pumps, fans and blowers
- Correct sizing, trim impellers, avoid throttling; remove unnecessary bends; use VFD.

#### 4. Compressed air system
- Fix air leaks (often 20–30% loss), reduce pressure setting, use intake air from cool place, switch off when not needed.

#### 5. Lighting
- Replace incandescent/CFL/tube lights with **LED**; use daylight, occupancy sensors, timers, separate switching.

#### 6. Thermal systems (boilers, furnaces)
- Control excess air, insulate pipes and furnaces, recover waste heat, return condensate, fix steam leaks and traps.

#### 7. Refrigeration and HVAC
- Raise chiller set point, clean condensers, use efficient compressors and thermal insulation.

#### 8. Process and management
- Avoid idle running, schedule production, monitor with energy meters, train staff, regular energy audits.

```text
Opportunity        Typical saving
LED lighting       40–60 % of lighting energy
VFD on fan/pump    20–50 % of drive energy
Air leak repair    10–30 % of compressor energy
PF correction      lower kVA demand charge
```

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Which approach saves more energy on fans and pumps than dampers or throttle valves?
   A. Fitting a larger motor
   B. Increasing the valve opening
   C. Using variable frequency drives
   D. Running at full speed all the time
   Answer: C. VFDs match speed to demand and save about 20-50 % of drive energy. (Key point: VFD use)

2. Which measure offers a large saving in compressed air systems?
   A. Raising the pressure setting
   B. Fixing air leaks, which often cause 20-30 % loss
   C. Drawing intake air from a hot place
   D. Running the compressor continuously
   Answer: B. Leaks are a major waste; fixing them and lowering pressure save energy. (Key point: Compressed air)

3. What lighting measure saves 40-60 % of lighting energy?
   A. Replacing LED with incandescent lamps
   B. Adding more lamps
   C. Using only tube lights
   D. Replacing incandescent/CFL/tube lights with LED
   Answer: D. LED retrofits, with sensors and timers, give the largest lighting saving. (Key point: Lighting)

4. How does pf correction with capacitors help in a plant?
   A. It increases kW consumption
   B. It reduces kVA demand, losses and penalties
   C. It increases voltage drop
   D. It raises the load current
   Answer: B. Capacitors supply reactive power locally, reducing kVA and current. (Key point: Power factor)

## Related in Industrial Power Distribution and Illumination

- [Energy audit technique and saving opportunities](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Aenergy-audit-technique-opportunities) — Industrial Power Distribution and Illumination, chapter 10
- [Energy and cost saving from lighting retrofit](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Alighting-retrofit-100kw) — Industrial Power Distribution and Illumination, chapter 10
- [Types of power supply system for industrial plant](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Aindustrial-supply-system-types) — Industrial Power Distribution and Illumination, chapter 1, asked 2×

## Related in other subjects

- [Energy saving calculation: lighting and motor](https://www.bctengineer.com/question.md?key=semester_6%2Fenergy_resources%3Alighting-motor-energy-saving-case) — Energy Resources, chapter 9
- [Geothermal energy uses and plant types in Nepal](https://www.bctengineer.com/question.md?key=semester_8%2Fpower_plant_design%3Ageothermal-use-nepal) — Power Plant Design, chapter 1
- [Identifying opportunity and finding a market gap](https://www.bctengineer.com/question.md?key=semester_7%2Fentrepreneurship_development%3Afinding-market-gap) — Entrepreneurship Development, chapter 2