Alternating Current (AC)
A current that flows alternately in one direction and then in the reverse direction. In North America, the standard for alternating current is 60 complete cycles each second. Such electricity is said to have a frequency of 60 hertz. Alternating current is used in power systems because it can be transmitted and distributed more economically than direct current.

Ancillary Services
Services necessary to support transmission of capacity and energy from resources to load while maintaining reliable operation of the transmission system.

Available Energy Capacity (AEC)
The amount of available energy on a transmission system.

Base Load
The minimum continuous load over a given period of time. Base load generating stations operate essentially at full output whenever possible.

Bulk Electricity
Large amounts of electric power at transmission voltages, generally to run industrial plants and operations.

Capacity
In the electric power industry, capacity has two meanings:
1. System Capacity: The maximum power capability of a system. For example, a utility system might have a rated capacity of 5000 megawatts, or might sell 50 megawatts of capacity.
2. Equipment Capacity: The maximum power capability of piece of equipment. For example, a generating unit might have a rated capacity of 50 megawatts.

Conventional Generation
Electricity that is produced at a generating station where the prime movers are driven by gases or steam produced by burning fossil fuels.

Current
The flow of electricity in a conductor. Current is measured in amperes.

Deregulation
Deregulation is the process by which governments removes selected regulations on business in order to (in theory) encourage the efficient operation of markets. The theory is that less regulation will lead to a raised level of competitiveness, therefore higher productivity, more efficiency and lower prices overall.

Direct Current (DC)
Current that flows continuously in the same direction (as opposed to alternating current). The current supplied from a battery is direct current.

Distribution
The process of transporting electric energy from the high voltage transmission grid directly to retail customers, generally on lines of 25 kV or less.

Electrical Energy
The quantity of electricity delivered over a period of time. The commonly used unit of electrical energy is the kilowatt-hour (kWh).

Electrical Power
The rate of delivery of electrical energy and the most frequently used measure of capacity. The basic unit is the kilowatt (kW).

Exchange
The transfer and return of electricity from one utility to another at different time periods or seasons to achieve a more economic or efficient overall system operation. Such transfers are possible because of differences in electricity demand, generation resource capability or system operating characteristics.

Facilities Study
An engineering study conducted by the Transmission Facility Owner to determine the required modifications to the grid, including the cost and scheduled completion date for such modifications, that will be required to provide the requested transmission service.

Frequency
The number of cycles through which an alternating current passes in a second. The North American standard is 60 cycles per second, known as 60 hertz.

Generation
The process of converting thermal, mechanical, chemical or nuclear energy into electric energy.

Grid
A network of electric power lines and connections.

Hertz (Hz)
The unit of frequency for alternating current. Formerly called cycles per second. The standard frequency for power supply in North America is 60 Hz.

ISO
Independent System Operator.

Interconnected System
A system consisting of two or more individual power systems connected together by tie lines.

Intertie (Interutility Tieline)
Transmission circuit used to tie or inter-connect two load areas of two utility systems.

Kilovolt (kV)
1000 volts

Kilowatt (kW)
The commercial unit of electric power; 1000 watts. A kilowatt can best be visualized as the total amount of power needed to light ten 100 watt light bulbs.

Kilowatt hour (kWh)
The commercial unit of electric energy; 1000 watt hours. A kilowatt hour can best be visualized as the amount of electricity consumed by ten 100-watt light bulbs burning for an hour. One kilowatt hour is equal to 3.6 million joules.

Load
The total amount of electricity required to meet customer demand at any moment. The load equation fluctuates depending on electricity use throughout any given day.

Load Factor
The ratio of the average load during a designated period to the peak or maximum load in that same period. Usually expressed in per cent.

Load Forecast
The anticipated amount of electricity required by customers in the future.

Megawatt (MW)
A unit of bulk power; 1000 kilowatts.

Megawatt hour (MW.h)
A unit of bulk energy; 1000 kilowatt hours

Need Study
An engineering study conducted by the Electric System Operator to determine the required modifications to the grid, including the cost, that will be required to meet the need of customers on the transmission system.

Point of Delivery (POD)
Point on the transmission provider's transmission system where the transmission grid connects to a receiving party for the delivery of electricity.

Point of Receipt (POR)
Point on the transmission provider's transmission system where the grid connects to a generator for the loading of electricity on to the transmission system.

Power System
The interconnected facilities of an electrical utility. A power system includes the generation, transmission, distribution, transformation, and protective components necessary to provide service.

Regulator
The regulating body in Alberta is the Alberta Utilities Commission (AUC). The AUC is an independent, quasi-judicial agency of the government of Alberta, with a mission to ensure that the delivery of Alberta's utility services take place in a manner that is fair, responsible and in the public interest.

Reserve Generating Capacity
The extra generating capacity required on any power system over and above the expected peak load. Such a reserve is required mainly for two reasons: (i) in case of an unexpected breakdown of generating equipment; (ii) in case the actual peak load is higher than forecast.

Substations
An electrical station where the high voltage electrical current from the transmission grid is reduced so that it is suitable for supply to customers.

System Impact Study
An assessment by the transmission provider of: (i) the adequacy of the transmission system to accommodate a transmission request for either Firm Point-to-Point Transmission Service or Network Integration Transmission Service; and (ii) whether any additional costs may be incurred in order to provide transmission service.

Transformer
An electromagnetic device for changing the voltage of alternating electricity.

Transmission
The process of transporting electric energy in bulk on high voltage lines from the generating facility to the local distribution company for delivery to retail customers.

Transmission System
The facilities owned, controlled or operated by the transmission provider that are used to provide transmission service.

Transmission Must Run (TMR)
Generation that was introduced to the Alberta market to support the over-burdened transmission system caused by the expanding demand of the southern region of the province.