Energy Use Analysis
What this domain tests
Energy use analysis converts bills and meter data into a baseline, an end-use picture, and a prioritized list of opportunities. Expect questions on rate structures, load factor, EUI, and weather normalization.
Core rules
- Separate energy (kWh, therms) from demand (kW); they are billed differently.
- Load factor = average demand ÷ peak demand over the period.
- Normalize with heating and cooling degree days before comparing years or buildings.
- Reconcile total consumption to end uses; unexplained residuals usually mean missing loads.
- Use site-to-source factors when comparing fuels (site 3.412 kBtu/kWh; source roughly three times that in the U.S.).
Worked example
A plant has a peak demand of 500 kW and average demand of 300 kW. Load factor = 300 ÷ 500 = 0.60, or 60%. With a $15/kW monthly demand charge, annual demand cost = 500 × 15 × 12 = $90,000. A measure that shaves 50 kW of peak saves $9,000/yr in demand charges alone, before any kWh savings - a key insight when load factor is low.
Traps
Comparing kWh across years without weather normalization; treating a billing demand ratchet as a simple average; confusing energy and demand savings; and ignoring power factor penalties.