Energy audit technique and saving opportunities

An energy audit is a systematic study of how energy is used in a plant: it measures energy inputs and uses, finds where energy is wasted, and recommends cost-effective measures to reduce consumption and cost without affecting production or safety.

Types

• Preliminary (walk-through) audit – a quick survey using existing bills and a site visit; finds obvious savings in a few days.
• Detailed audit – a full study with instruments, energy balance of each section and detailed cost–benefit of each measure.

Energy audit technique (steps)

1. Pre-audit planning – meet management, form audit team, collect plant layout, single-line diagram, production data and 1–3 years of electricity bills.
2. Data collection – list connected loads (motors, lighting, compressors, furnaces), nameplate ratings and operating hours.
3. Measurement – use portable instruments: power analyser (kW, kVA, pf, harmonics), clamp meters, lux meter, tachometer, thermal camera, flow and pressure meters.
4. Analysis – prepare load curve, energy balance (where each kWh goes), specific energy consumption (kWh per unit product), compare with benchmarks; identify losses.
5. Identify energy saving opportunities (ESOs) and estimate savings.
6. Economic analysis – cost of each measure, annual saving, simple payback, NPV/IRR; rank them (no-cost, low-cost, high-investment).
7. Report and action plan – recommendations with priority and responsibility.
8. Implementation and monitoring – verify savings by measurement, then repeat audit periodically.

Plan → Collect data → Measure → Analyse
  ↑                                 ↓
Monitor ← Implement ← Report ← Find ESOs & costs

Energy saving opportunities in industrial electrical systems

Typical savings from an audit are 10–30 % of the electricity bill, many with payback under two years.