Global Adjustment and Peak Demand Factor

Class A customers are assessed their portion of GA costs based on the percentage that their consumption contributes to the top five system coincident peaks during a predetermined base period, referred to as their Peak Demand Factor.

For example, if a Class A customer is assessed to be responsible for one per cent of Ontario's coincident peak demand for the five highest hours of a set base period, they will be charged for one per cent of total GA costs through the next adjustment, or billing period.

Base period

Class A customers are assessed their portion of GA costs based on the percentage that their consumption contributes to the top five system coincident peaks during a predetermined base period (May 1-April 30) and will be charged their percentage of total GA costs through the next adjustment, or billing period (July 1-June 30).

Base Period (Peak-setting Period)

Adjustment Period (Billing Period)

May 1, 2020 to April 30, 2021

July 1, 2021 to June 30, 2022

May 1, 2019 to April 30, 2020

July 1, 2020 to June 30, 2021

May 1, 2018 to April 30, 2019

July 1, 2019 to June 30, 2020

 May 1, 2017 to April 30, 2018

 July 1, 2018 to June 30, 2019

May 1, 2016 to April 30, 2017

July 1, 2017 to June 30, 2018

May 1, 2015 to April 30, 2016

July 1, 2016 to June 30, 2017

May 1, (Year X) to April 30, (Year X+1)

July 1, (Year X+1) to June 30, (Year X+2)


Top 5 Peaks: Hours & System-Wide Consumption

The table below shows the final peak hours and the corresponding adjusted demand for the past base period. Embedded generation is included, as it represents Ontario demand that was met through local generation.

 

Base Period: May 1, 2021 to April 30, 2022

Original Rank Date

Hour Ending (EST) Allocated Quantity
of Energy Withdrawn
(MWh)
Embedded
Generation (MWh)
Energy
Storage
Injections (MWh)
Total* (MWh) 
1 August 24, 2021 17 22,428.110 984.600 2.992 23,409.718
2 August 26, 2021 14 22,424.464 1,606.355 0.002 24,030.817
3 August 23, 2021 17 22,055.276 1,016.697 2.982 23,068.991
4 August 9, 2021 17 21,812.520 1,129.026 2.986 22,938.560
5 August 25, 2021 20 21,734.689 321.601 1.193 22,055.097

*The value in the Total (MWh) column is the number used to calculate a customer’s Peak Demand Factor.

For historical peaks, download the Top 5 Peaks: Hours & System-Wide Consumption.

Calculating your Peak Demand Factor

After the IESO establishes the final top five Ontario demand peaks using adjusted AQEW for a base period, the IESO and LDCs then look at each Class A customer's consumption during those five hours (coincident peaks) to calculate their corresponding portion of peak demand. This portion is called a peak demand factor and is used to determine a customer's allocation of costs for the adjustment or billing period.

Example Calculation

A customer’s consumption during the top 5 demand peak hours (MWh)

3.128

4.458

3.981

4.123

4.325

20.015

÷

Sum of Top 5 System-wide Consumption Peaks (MWh)

115,503.183

=

Peak Demand Factor

0.00017329


How Class A customers are charged GA

The Class A customer's Peak Demand Factor is used to calculate monthly GA charges during the adjustment or billing period. This is done by multiplying the monthly Ontario-wide total GA costs by the customer's Peak Demand Factor.

Example Calculation

System-wide GA costs for a given month 

$999.6 M

See Total GA costs ($M)

x

Your Peak Demand Factor from example above

0.00017329

=

Your GA charge for the month

$173,220.68