--- title: "Need of energy audit and technique" subject: "Industrial Power Distribution and Illumination" chapter: 10 key: "semester_6/industrial_power_distribution_and_illumination:energy-audit-need-technique" source: https://www.bctengineer.com/q/semester_6/industrial_power_distribution_and_illumination/energy-audit-need-technique site: BCT Engineering --- # Need of energy audit and technique Industrial Power Distribution and Illumination · Chapter 10: Electrical Energy Audit in Industry - Asked in: 2077 Chaitra, 8 marks; 2073 Bhadra, 4 marks; 2070 Bhadra, 8 marks (asked 3 times) - Video: [Energy Audit - Need for Energy Audit - Types of Energy Audit](https://www.youtube.com/watch?v=OsJ-j1LHTHk) — Energy Insight Hub (EIH) - 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-audit-need-technique - Whole chapter: https://www.bctengineer.com/md/semester_6/industrial_power_distribution_and_illumination/chapter-10 ## Question Explain the need of energy audit for an industry and energy audit technique. ## Short answer Energy audit identifies waste, reduces costs, improves productivity, and helps compliance. The technique follows pre-audit (data collection, walk-through), detiled audit (measurements, energy balance, ECO identification, economic analysis), and post-audit (report, implementation, monitoring). ## Answer **Energy audit** is the systematic study of how energy is used in an industry, to find where it is wasted and to recommend cost-effective measures for saving it. (India's Energy Conservation Act, 2001, a definition also widely used in Nepal's energy efficiency programmes, defines it as "verification, monitoring and analysis of energy use, with a technical report containing recommendations and an action plan to reduce consumption".) #### Need of energy audit for an industry 1. **Reduce energy cost** – energy is a major part (10–40%) of production cost; savings of 10–30% are common. 2. **Identify waste** – leaks, idle running, oversized motors, poor power factor, poor insulation. 3. **Improve productivity and competitiveness** – lower unit cost of product. 4. **Benchmarking** – compare specific energy consumption (kWh/ton) with best practice. 5. **Planning** – basis for investments in efficient equipment, with payback calculation. 6. **Reduce demand charges and penalties** – peak load management, pf improvement. 7. **Environment** – lower fuel use and CO₂ emissions. 8. **Equipment reliability** – detect overloaded, overheating or unbalanced equipment. 9. **Legal and policy compliance** – government programmes and standards. #### Energy audit technique (methodology) **1. Pre-audit (planning) phase** - Form the audit team, meet management, set objectives. - Collect data: energy bills (12–36 months), production records, single-line diagram, equipment list. - Do a walk-through survey to see the major energy users. **2. Audit (execution) phase** - Take detailed measurements with instruments: power analysers, clamp meters, lux meters, flue gas analysers, thermal cameras, flow and pressure meters. - Prepare an **energy balance**: where each kWh/litre goes (motors, lighting, compressors, HVAC, furnaces). - Calculate specific energy consumption; study the load profile, pf and losses. - Identify energy conservation opportunities (ECOs). - Techno-economic analysis: savings, investment, **simple payback = investment / annual savings**, NPV/IRR. **3. Post-audit phase** - Prepare a report with recommendations ranked as no-cost, low-cost and high-cost. - Implement measures; monitor and verify savings (M&V); repeat the audit periodically. ```text Pre-audit ─► Data & walk-through ─► Measurements ─► Energy balance ─► Find ECOs ─► Cost-benefit ─► Report ─► Implement ─► Monitor & verify ``` **Types:** preliminary (walk-through) audit – quick, uses existing data; detailed audit – complete measurement and analysis of all systems. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What is an energy audit? A. Buying cheaper electricity from the utility B. Replacing all equipment with new ones C. Installing energy meters only D. A systematic study of energy use to find waste and recommend cost-effective savings Answer: D. An audit studies how energy is used, finds where it is wasted and recommends measures to save it. (Key point: Energy audit definition) 2. Which activity belongs to the pre-audit phase? A. Collecting energy bills, production records and single-line diagram, and a walk-through survey B. Measuring with power analysers C. Implementing recommended measures D. Monitoring and verifying savings Answer: A. Pre-audit means planning, data collection and a walk-through survey. (Key point: Pre-audit phase) 3. What is the purpose of an energy balance in the audit phase? A. To balance the electricity bill B. To show where each unit of energy goes (motors, lighting, compressors, etc.) C. To balance phase currents D. To find the cost of the audit Answer: B. It identifies how much energy each section uses and where it is lost. (Key point: Energy balance) 4. How is simple payback computed in techno-economic analysis? A. Annual savings / investment B. Investment x annual savings C. Investment / annual savings D. Investment - annual savings Answer: C. Simple payback (years) = investment divided by annual savings. (Key point: Simple payback) ## 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 audit definition and process](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Adefine-energy-audit-process) — Industrial Power Distribution and Illumination, chapter 10 - [Execution phase of energy audit](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Aenergy-audit-execution-phase) — Industrial Power Distribution and Illumination, chapter 10 ## Related in other subjects - [Energy audit types and audit procedure](https://www.bctengineer.com/question.md?key=semester_6%2Fenergy_resources%3Aenergy-audit-types-procedure) — Energy Resources, chapter 9 - [Energy audit instruments and energy balance](https://www.bctengineer.com/question.md?key=semester_6%2Fenergy_resources%3Aenergy-audit-instruments-measurements) — Energy Resources, chapter 9 - [Preparing and presenting an energy audit report](https://www.bctengineer.com/question.md?key=semester_6%2Fenergy_resources%3Aenergy-audit-report-preparation-presentation) — Energy Resources, chapter 9 - [Need for equalization and basic technique](https://www.bctengineer.com/question.md?key=semester_7%2Fwireless_communication%3Aequalization-need-basic) — Wireless Communication, chapter 5