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Facility energy, defined
Definitions of the terms that decide what a facility pays for electricity and what its equipment does when the supply misbehaves. Each page answers the question in the first paragraph, then gives the standard, the threshold and the arithmetic. Written for people who have to defend a number.
What the bill charges you for
- Power factor — Power factor is real power (kW) divided by apparent power (kVA) — the share of the current a facility draws that does useful work.
- Demand charge — A demand charge bills a facility for the highest average power, in kilowatts, that it drew during any single measurement interval of the month — usually 15 minutes.
- Interval data — Interval data is electricity consumption recorded in fixed, repeating time blocks — most often 15 minutes — rather than as a single monthly total.
- PJM demand response — PJM demand response pays commercial and industrial facilities to reduce electrical load when the grid operator calls on them.
- kW, kWh and kVA — A kilowatt (kW) is a rate of power.
How the electricity behaves
- Power quality — Power quality is how closely the voltage and current supplied to equipment match an ideal, undistorted sine wave at nominal magnitude and frequency.
- Voltage sag — A voltage sag is a short reduction in RMS voltage to between 10% and 90% of nominal, lasting from half a cycle to one minute.
How a facility measures itself
- Submetering — Submetering is the measurement of energy consumption at points downstream of the utility's revenue meter — per tenant, per floor, per production line or per item of equipment.
- Tenant billing — Tenant billing is the process of allocating a building's utility cost to its tenants based on measured consumption rather than an assumption, and invoicing them for it.
- Energy benchmarking — Energy benchmarking is the measurement of a building's annual energy use, normalised for size and often for use type and weather, and compared against similar buildings.
What you do with the measurement
- Condition monitoring — Condition monitoring is the measurement of a machine's physical state while it runs — vibration, temperature, current draw — so that deterioration is detected before it becomes failure.
- Fault detection and diagnostics — Fault detection and diagnostics, or FDD, is software that continuously compares how equipment is operating against how it should operate, flags the differences as faults, and identifies the probable cause.
- Monitoring-based commissioning — Monitoring-based commissioning, or MBCx, combines permanent metering and analytics with an ongoing commissioning process, so that performance problems are found and corrected continuously rather than during a one-off study.
- HVAC monitoring — HVAC monitoring is the continuous collection and analysis of operating data from heating, ventilation and air conditioning equipment — temperatures, damper positions, run status, electrical draw — to find equipment operating incorrectly while still running normally enough not to alarm.
- How utility energy incentives get paid — Utility efficiency incentives pay for verified savings from specific approved measures — not for equipment or software.