CEM Certified Energy Manager Audit & Billing 4 — Questions and Answers
Question 1: During a walk-through audit, an auditor observes that lighting in a warehouse remains on 24/7 despite occupancy only during two 8-hour shifts. The FIRST recommendation should be:
- Replace all fixtures with LEDs immediately
- Install occupancy sensors or timers to match operating hours (Correct answer)
- Reduce lamp wattage by 50%
- Add skylights for daylighting
Correct answer: Install occupancy sensors or timers to match operating hours
Occupancy sensors or timers are typically low-cost operational measures that immediately eliminate lighting waste during unoccupied periods.
Question 2: Which instrument is MOST appropriate for measuring true power (kW) and power factor simultaneously in a facility audit?
- Clamp-on ammeter
- Power quality analyzer (Correct answer)
- Digital multimeter
- Thermal imaging camera
Correct answer: Power quality analyzer
A power quality analyzer measures voltage, current, true power (kW), apparent power (kVA), and power factor simultaneously.
Question 3: A simple payback period (SPP) is calculated as:
- Annual energy savings divided by installed cost
- Installed cost divided by annual energy cost savings (Correct answer)
- Net present value divided by discount rate
- First-year savings multiplied by project life
Correct answer: Installed cost divided by annual energy cost savings
Simple payback period equals the total installed cost divided by the annual energy cost savings, giving years to recover the investment.
Question 4: What does the term 'demand ratchet' most directly affect on a commercial electricity bill?
- The energy charge rate per kWh
- The minimum billable demand for future months (Correct answer)
- Power factor penalty calculations
- Reactive power charges
Correct answer: The minimum billable demand for future months
A demand ratchet sets a minimum billable demand (e.g., 75% of peak) for subsequent months, even if actual demand is lower.
Question 5: An M&V plan following IPMVP Option B (Retrofit Isolation with Short-Term Measurement) requires:
- Whole-facility metering before and after retrofit
- Metering only the retrofitted system using short-term post-retrofit measurements (Correct answer)
- Stipulated savings without any post-retrofit measurement
- Continuous metering of all energy systems
Correct answer: Metering only the retrofitted system using short-term post-retrofit measurements
IPMVP Option B isolates and meters only the retrofitted equipment, using short-term post-installation measurements to verify savings.
Question 6: In an energy audit report, which financial metric accounts for the time value of money?
- Simple payback period
- Net Present Value (NPV) (Correct answer)
- Annual energy cost savings
- Energy cost intensity
Correct answer: Net Present Value (NPV)
NPV discounts future cash flows to present value, properly accounting for the time value of money unlike simple payback.
Question 7: A CEM finds that a facility's monthly bills include a 'customer charge' that remains constant regardless of consumption. This charge primarily covers:
- Energy consumed at off-peak rates
- Fixed utility infrastructure and administrative costs (Correct answer)
- Demand charges for peak periods
- Fuel adjustment costs
Correct answer: Fixed utility infrastructure and administrative costs
The customer charge is a fixed monthly fee covering the utility's cost of metering, billing, and maintaining the service connection.
CEM Certified Energy Manager Audit & Billing 4
During a walk-through audit, an auditor observes that lighting in a warehouse remains on 24/7 despite occupancy only during two 8-hour shifts.
The FIRST recommendation should be: