A pricing mechanism based on the average total system cost of providing a unit of electricity (megawatt hours for wholesale/kilowatt hours for retail) during a specified period.

The minimum continuous load or demand required over a given period of time at a steady rate. Variations in load due to temperature, production, etc. are in addition to base load.

The rate at which electricity is delivered to or by a system in a given instant, or averaged over a designated period. Usually expressed in kilowatts (kW) or megawatts (MW).

Measuring and recording the amount of electricity used during a defined period, such as every five or fifteen minutes increments.

A unit of electrical energy which is equivalent to one kilowatt of power used for one hour. One kilowatt-hour is equal to 1,000 watt-hours (the energy needed to burn ten 100 watt lightbulbs for one hour).

Ratio of the amount of electricity used during a specific time period to the maximum possible use during that period, expressed as a percentage.

An Approximation of the amount of energy typically taken during each hour by a consumer or class of consumers over a defined period. Load profiles are needed for consumers who do not have interval meters, and are used to allocate total kWh usage over the months to each hour.

The variation in customer or system demand over a specified period of time (e.g., daily, weekly or yearly).

Unit of electricity equal to one million watts or one thousand kilowatts. Typically used to measure power production capacity of a generating station or the maximum demand of an electricity consumer.

The period during a load cycle (day, week, month or year) when the demand on a power system is significantly below peak demand in that load cycle. Off peak covers the hours of 11PM to 7AM in Ontario.

In electricity, the maximum demand occurring during a specified period of time. Also known as peak load.

The percentage of power in an alternating current circuit that is actually consumed by a customer’s electrical equipment compared to the total apparent power supplied.

A market in which commodities are traded for immediate or near-immediate delivery.

A supply arrangement for electricity delivered to meet your demand on weekdays between 7AM and 11PM. This period is considered peak demand and rates are usually higher. Note this excludes holidays. This is sometimes referred to as a “Peak Block”

A supply arrangement for electricity delivered to meet your demand seven days per week, 24 hours per day. This can also be called a “base block” of electricity.

A supply arrangement to deliver electricity 24 hours per day during the work week. This exludes holidays.

A blended supply arrangement uses different blocks of electricity delivery, usually mixing 5x16 (peak block), 7x24 (base block) or 5x24 supply delivery to match a user’s consumption pattern.

From the IESO website:

HOEP is the hourly price that is charged to Local Distributing Companies and other non-dispatchable loads. HOEP is also paid to self-scheduling generators.

HOEP is defined as the hourly arithmetic average of the uniform Ontario energy price determined for each of the 12, 5-minute dispatch intervals in a particular hour.

On Peak average price is the straight arithmetic average of HOEP in hours 8 to 23 EST, Monday to Friday (5 x 16). Off Peak average price is the straight arithmetic average of HOEP for all remaining hours in the week.

Weeks with statutory holidays will cause the on-peak average to be calculated using 4 weekdays (4 x 16).

The wholesale market does not use a formal definition of on and off-peak hours. The IESO is providing this calculation purely for information purposes, and will continue to use this definition throughout the year.

NOTE: At the request of market participants, the IESO has shifted the On Peak definition by one hour (from 7 to 22, to 8 to 23) as of December 2004, to better reflect the industry practice.