Monthly Generator Disclosure Report

Discontinued as a result of market rule amendment MR-00387-Q00. For generator output and capability data please refer to the Hourly Generator Output & Capability Reports.

In the Ontario market, most generating stations are considered to be "dispatchable." That is, they only operate when directed to by the IESO to meet the demands of consumers in the Ontario market.

The IESO will select the generating stations that are dispatched to operate to meet consumer demands in such a manner as to minimize the overall cost of electricity supply. Therefore there will be many instances where generation stations are available to run but are not dispatched by the IESO because they are not needed to meet market demand at that time.

It is also important to understand that there are different "classes" of generating facilities in the Ontario market. Nuclear generation plants and many hydroelectric plants are considered "base load" plants. Base load plants tend to have high capital costs and relatively low operating costs and are designed to run most of the time. These types of plants would typically have "Actual Capacity Factors" in excess of 70 - 80%. Natural gas and oil fuelled plants and hydroelectric facilities with water storage capability are considered "peaking" plants. They are designed to run to meet electrical demand when it is at its highest. These plants would typically have "Actual Capacity Factors" of 10% - 30%. Finally there are "intermediate load" plants, typically coal plants in the Ontario market. They would typically have "Actual Capacity Factors" of 40% - 60%.

In addition, certain generating stations in Ontario are subject to other limits on their production. For example, the Total Capability Factor and the Actual Energy Production from hydroelectric units is subject to the availability of water and to certain regulatory and citizenship constraints. Fossil fuel plants are subject to emission and other environmental limits.

• The Maximum Continuous Rating (MCR)
• The Planned Capability Factor
• The Total Capability Factor
• The Actual Energy Production
• The Actual Production Factor

"Maximum Continuous Rating" is defined as the maximum output (MW) that a generating station is capable of producing continuously under normal conditions over a year. Under ideal conditions, the actual output could be higher than the MCR.

"Planned Capability Factor" is the ratio of energy that could have been delivered by a generating station with pre-approved planned unit limitations in effect, to the energy that could have been delivered if the station had operated continuously at the Maximum Continuous Rating, over the same period of time.

"Total Capability Factor" is the ratio of energy that could have been delivered by a generating station with pre-approved planned and forced unit limitations in effect, to the energy that could have been delivered if the station had operated continuously at the Maximum Continuous Rating, over the same period of time.

"Actual Energy Production" is the amount of energy a generating station produced during the month, expressed in megawatt-hours (MWh).

"Actual Production Factor" is the ratio of energy that was produced by a generating station, to the energy, over the same period of time, that could have been delivered if the station had operated continuously at the Maximum Continuous Rating.

The report as published, is sorted in descending order of the Actual Energy Production.

The Ontario Zone Diagram identifies the zones where each generating station is mapped.