Terms & Definitions

Active Energy— Electricity used to operate resistive loads, such as incandescent lighting and heating elements.  Also called real energy. 

Base Load — The sum of the loads in a facility that cannot be used for demand management.  These are typically key processes or minimum equipment operating levels required to maintain building comfort, production levels or product quality.

Billing Period— The time period over which the utility assesses billing charges.  Most utilities use a billing period of one month.

Consumption— The amount of electricity supplied to a customer over the billing period.  Utilities typically measure electricity consumption in kilowatt-hours (kWh).  10 100 watt light bulbs operating for 1 hour consume 1 kWh, 10x100 wattsx1 hour = 1,000 Wh = 1 kWh. 1 100 watt light bulb operating for 10 hours consumes 1 kWh, 1x100 wattsx10 hours = 1,000 Wh = 1 kWh.

Controllable Object— A load within a facility that can be used to reduce a facility’s demand.  Examples of controllable objects include heaters, furnaces, chillers and compressors.

Demand— The amount of energy consumed over a specific time interval.  Virtually all commercial and industrial customers pay demand charges on their utility bills.  Utilities typically calculate demand as the amount of active energy consumed over a 15 minute to 1 hour time interval.  10 100 watt light bulbs operating for 1 hour create a demand level of 1 kW, (10x100 wattsx1 hour)/1 hour = 1000 W = 1 kW.

Demand Management— An approach to reducing energy costs by reducing a facility’s peak demand, which lowers utility bill demand charges.

Demand Response— The ability of a facility to reduce demand levels over a specific time period or over the long term.  Curtailment is a short term demand response action to an emergency situation.  Sustained demand response is an overall lowering of peak demand levels over the long term.

Embedded Operational Intelligence™- Technology that incorporates a user’s unique understanding of their facility’s operation into predictive energy management software, resulting in an intelligent automation solution enabling savings without negative impact to facility processes.

Enhanced Automation— The use of comprehensive monitoring and control systems such as the Energy Director™ to better manage energy costs.

Interval Data— Data provided by a utility which shows a facility’s energy consumption over time.  Interval data is typically measured every 15 minutes to 1 hour.

Kilowatt (kW)— The unit of measure for demand or power.  See demand.  Utility demand charges are typically rated in kW.

Kilowatt-hours (kWh)— The unit of measure for consumption.  See consumption.  Utility consumption charges are typically rated in kWh.

Local Area Network (LAN)— The LAN provides communication between computers and the Energy Director.  A web browser, such as Microsoft Internet Explorer, uses the LAN to communicate with the Energy Director.

Load — The amount of electric power required by equipment or a process.  Also used to generically describe specific equipment or types of equipment.

Load Factor — The ratio (%) of the average demand during the billing period to the peak demand occurring during that same billing period.  High load factors indicate a stable demand level.  Low load factors are indicative of highly variable demand levels.  Low load factors typically indicate good potential for demand management and cost savings.

Peak Demand — The maximum demand level at a facility during the utility billing period.  Demand rates are applied to the facility’s peak demand level to create the demand charges on utility bills.

Power— The amount of energy required over a specific time period.  See demand.

Power Factor — The ratio (%) of reactive energy to total energy.  Total energy is the combination of active and reactive energy used at a facility.  Utilities typically use a billing adjustment based on power factor to charge for above average reactive energy use.  All else being equal, a facility operating a large number of motors would have a lower power factor than a facility with fewer motors.

Reactive Energy — Electricity used to generate magnetic fields in inductive loads, such as motors or compressors.  Utilities have to generate reactive energy as well as active energy in order to reliably provide power to their customers. 

Real Energy — See Active Energy.

Watt — The unit of measure for demand or power.  See demand.  1,000 W = 1 kilowatt kW, 1,000,000 W = 1 MW.