CEM Methods and Strategies 5 — Questions and Answers
Question 1: A CEM is tasked with reducing plug load energy consumption in an office building. Which strategy is MOST effective?
- Installing occupancy sensors on lighting circuits only
- Deploying smart power strips and enforcing plug load management policies (Correct answer)
- Replacing all computers with thinner monitors
- Upgrading the electrical distribution panels
Correct answer: Deploying smart power strips and enforcing plug load management policies
Smart power strips eliminate phantom loads from peripherals, and a formal plug load policy addresses the behavioral and procurement aspects that hardware alone cannot solve.
Question 2: Which strategy BEST supports continuous energy improvement under ISO 50001?
- Conducting a one-time energy audit every five years
- Establishing energy performance indicators (EnPIs) and monitoring them regularly (Correct answer)
- Outsourcing all energy decisions to the utility company
- Documenting energy use only when bills increase
Correct answer: Establishing energy performance indicators (EnPIs) and monitoring them regularly
ISO 50001 requires ongoing tracking of EnPIs to demonstrate continual improvement and catch performance degradation before it becomes costly.
Question 3: When evaluating lighting upgrade strategies, what is the advantage of using a lighting control system in addition to LED fixtures?
- It eliminates the need for any ballasts
- It captures additional savings through dimming, occupancy, and daylight harvesting controls (Correct answer)
- It allows the use of lower-efficacy lamps safely
- It removes the requirement for an emergency lighting system
Correct answer: It captures additional savings through dimming, occupancy, and daylight harvesting controls
Controls layer additional savings on top of lamp efficiency by ensuring lights operate only when and at the level needed, often doubling the savings from lamp replacement alone.
Question 4: A CEM discovers that a large fan system is operating at full speed continuously despite variable airflow needs. What is the BEST corrective strategy?
- Reduce the fan blade diameter
- Install a variable frequency drive (VFD) on the fan motor (Correct answer)
- Add inlet vane dampers to throttle airflow
- Replace the fan with a smaller fixed-speed unit
Correct answer: Install a variable frequency drive (VFD) on the fan motor
A VFD reduces fan speed to match actual demand; because fan power varies with the cube of speed, small speed reductions yield dramatic energy savings.
Question 5: What is 'energy procurement strategy' and why is it important for large energy users?
- Scheduling preventive maintenance on energy equipment
- Actively managing when, how, and from whom energy is purchased to minimize cost and risk (Correct answer)
- Selecting lighting fixtures based on energy labels
- Designing new facilities to meet code minimum efficiency
Correct answer: Actively managing when, how, and from whom energy is purchased to minimize cost and risk
Large users can negotiate rates, choose contract structures, hedge against price volatility, and access green tariffs — all of which significantly impact energy costs beyond efficiency measures alone.
Question 6: A CEM is evaluating a building envelope improvement project. Which metric BEST quantifies the energy benefit of adding roof insulation?
- U-value reduction and resultant heating/cooling load reduction (Correct answer)
- Visible light transmittance (VLT) of the roof membrane
- Air changes per hour at 50 Pa (ACH50)
- Solar heat gain coefficient (SHGC) of the assembly
Correct answer: U-value reduction and resultant heating/cooling load reduction
U-value (thermal transmittance) directly measures heat flow through the assembly; reducing U-value lowers the heating and cooling energy required to maintain comfort.
Question 7: Which approach BEST describes an 'energy treasure hunt' as used in industrial energy management?
- A financial analysis to identify the highest-value capital projects
- A structured team walkthrough to identify operational waste and no-cost improvement opportunities (Correct answer)
- A competitive benchmarking study against industry peers
- An automated software scan of utility bill data for billing errors
Correct answer: A structured team walkthrough to identify operational waste and no-cost improvement opportunities
An energy treasure hunt is a focused, team-based event — popularized by Toyota and the DOE — where cross-functional staff walk the facility to spot waste, leaks, and behavioral fixes in real time.
CEM Methods and Strategies 5
A CEM is tasked with reducing plug load energy consumption in an office building.
Which strategy is MOST effective?