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Global Adjustment for Class B

​Class B customers are defined as those with a peak demand over 50 kilowatts and less than or equal to one megawatt.  The change in this definition came into effect on January 1, 2017. See Ontario regulation.

For those consumers billed by their local distribution company (LDC) or their retail contract provider​, there are three variations of the Global Adjustment rate (1st Estimate, 2nd Estimate, and Actual) that are posted at different times of the month. Since there is no financial difference to customers, the LDC can select, depending on billing timelines, which rate to apply to customer bills.

For Class B market participants who are billed by the IESO, the Actual Global Adjustment rate is applied to the settlement statement for the last trade day of the month and the invoice.

The IESO calculates the Global Adjustment (GA) rate each month. This rate varies depending on the following factors:

  • Trends in the electricity market:​ most contract payments and regulated rates are tied to the revenues generators receive through the IESO wholesale market. As a result, the GA can go up if the market price is low, and vice versa.
  • The addition of new generator contracts and programs that contribute to total GA costs
  • Trueups to account for the difference between estimates and Actual GA costs

How to Calculate Your Bottom Line

For those Class B customers paying the market price or on a retail contract.

Year-to-Date December 2016
Hourly Price (Weighted Average) ¢/kWh 1.66 2.09
Global Adjustment ¢/kWh 9.66 8.71
Your Bottom Line ¢/kWh 11.32 10.79

The IESO provides three variations of the Global Adjustment for Class B customers - used by LDCs to bill customers depending on their billing cycle.

1st Estimate

  • The 1st Estimate for a given month comprises three components - an estimate of the GA costs based on the previous month, an estimate of Ontario demand for the given month, and a true up accounting for the difference between the previous month's 1st Estimate and the actual rate.
  • The 1st Estimate for the upcoming month is published on the last business day of the preceding month. For example, the ​1st Estimate for April is published at the end of March.

2nd Estimate

  • The 2nd Estimate is a separate calculation based on actual GA costs and demand information available at the time it is published, an estimate for GA and demand for the remaining days of the month, and a true up accounting for the difference between the previous month's 2nd Estimate and the actual rate.
  • The 2nd Estimate for a given month is published on the last business day of that month. For example, the 2nd Estimate for April is published at the end of April.


  • The Actual rate, based on actual electricity demand and GA costs, is published on the tenth business day of each month. For example, the Actual rate for April is published on the tenth business day of May.

Global Adjustment Estimates and Actual Rates

Recent 1st, 2nd Estimate and Actual rates for Class B customers are posted below.  See also Global Adjustment Archive.  

1st Estimate ($/MWh)66.87105.59
2nd Estimate ($/MWh)86.77
Actual Rate ($/MWh)82.27


1st Estimate ($/MWh)84.23103.8490.22121.15104.05116.5076.6785.6970.6097.20122.71105.94
2nd Estimate ($/MWh)92.1496.78102.99111.77114.9393.6084.1270.5091.48117.80115.0078.72
Actual Rate ($/MWh)91.7998.51106.10111.32107.4995.4583.0671.0395.31112.26111.0987.08


1st Estimate ($/MWh)55.4969.8136.0467.0594.1692.2888.8888.0582.7063.7176.23114.62
2nd Estimate ($/MWh)61.6140.9557.4092.6897.3097.6884.1373.5571.9171.93124.4888.09
Actual Rate ($/MWh)50.6839.6162.9095.5996.6895.4078.8380.1067.0375.44113.2094.71


Global Adjustment Estimate and Actual Costs

The 2nd Estimate and Actual Total GA costs are posted below. See also Global Adjustment Archive.

2nd Estimate (M$)959.4
Actual (M$)927.7


2nd Estimate (M$)1091.81049.01101.71051.61031.6997.31001.8910.1973.21094.21128.9968.5
Actual (M$)1070.61063.71120.11090.71060.8995.3981.8878.6967.71062.31076.1965.5


2nd Estimate (M$)626.0474.0671.0842.5871.4892.9912.6838.1723.8704.01158.31021.6
Actual (M$)628.1458.8706.8928.7939.1943.1904.1879.2713.4742.61119.3999.6


For historical Global Adjustment values, see Global Adjustment Archive.