Energy Management and Audit
Energy Management and Audit
This domain tests how candidates establish an energy baseline, choose the right audit depth, and turn measurements into auditable savings. BEE's CEM syllabus expects familiarity with preliminary and detailed audits, instrument selection, energy balances, and ISO 50001's Plan-Do-Check-Act logic.
Core rules
- A preliminary audit scopes major energy users and quick wins; a detailed audit meters representative loads, builds mass/energy balances, and quantifies savings with accuracy levels.
- Normalize energy use for production, weather, or occupancy before comparing periods. A baseline is valid only within its stated boundary and operating regime.
- Report each conservation measure with capital cost, annual kWh and INR savings, simple payback, and assumptions. Verify savings after implementation with measurement and verification.
Worked example
A pump averages 55 kW input over 6,000 operating hours. Annual energy = 55 × 6,000 = 330,000 kWh. At INR 8/kWh, cost = INR 2.64 million. A variable-frequency drive is expected to cut energy 20%: 66,000 kWh/year, or INR 528,000/year. If the installed cost is INR 1.5 million, simple payback = 1,500,000 ÷ 528,000 = 2.84 years. The reasoning must state that 55 kW is measured average input, not nameplate output, and that 6,000 hours is actual run time.
Traps
Using rated motor kW instead of measured draw; ignoring part-load efficiency; comparing months with different production; omitting instrument calibration and uncertainty; and claiming savings without a baseline adjustment.