Global adjustment on Ontario electricity bills: what a property team should check every month

Ask a property manager to explain the electricity bill for a mid-sized building in Ontario and the conversation usually stops at the global adjustment line. It is large, it changes every month, and it is set by a mechanism that most people have never had explained. That makes it both the line most likely to be wrong and the line least likely to be questioned.

This article covers the mechanism as the Independent Electricity System Operator (IESO) describes it, and then the practical checks a monthly review runs on the line. It is written for property teams, not for energy traders, so it stays with what shows up on the bill.

What global adjustment pays for

The IESO's global adjustment explainer states that it covers the cost of building new electricity infrastructure in the province, regulated rates paid to electricity suppliers under contract, and the costs of delivering the province's energy efficiency and conservation programs. In other words, it is the difference between what generators are paid under regulation and contract and what the wholesale market price recovers. When the market price is low, the global adjustment is high, and the total is what customers actually pay for the electricity commodity.

How it appears depends on the customer. Residential and small business customers on regulated pricing have it built into their rates. Medium-sized businesses see it as a separate line item. Large customers may see it computed on a completely different basis.

Class A and Class B

The IESO explains that Class A customers are medium and large businesses able to participate in the Industrial Conservation Initiative (ICI), and that a Class A customer is billed based on its share of total demand during Ontario's top five peak demand hours: a customer responsible for two percent of Ontario's peak demand is billed for two percent of the province's total global adjustment costs. Most electricity customers in Ontario are Class B; once the amount billed to Class A customers has been settled, the remainder is passed on to Class B customers.

The eligibility rules are on the IESO's Class A eligibility page. Customers with an average monthly peak demand above 1 MW during the base period can opt in to the ICI, and since 2017 customers in targeted manufacturing and industrial sectors and greenhouses with an average monthly peak demand above 500 kW have been eligible as well. A Class A customer's peak demand factor is based on its contribution to the five highest provincial peak hours over the base period, which runs from May 1 to April 30, and that factor sets its share of global adjustment for the following adjustment period.

Why the rate on a Class B bill can be an estimate

The IESO publishes the Class B rate three times for each month on its global adjustment rates page: a first estimate before the month, a second estimate during it, and the actual rate after the month closes, all in cents per kWh. Which one appears on a bill depends on when the utility issued the bill. A bill issued early in the month may carry the first estimate; a later bill may carry the second estimate or the actual.

For a property team this has a consequence that is easy to miss: two buildings with identical consumption in the same month can show different global adjustment charges because they were billed on different days. Comparing cost per kWh across buildings without knowing which rate version each bill used produces false anomalies, and hides real ones.

The monthly checks

1. Which class is each account? Keep it on the meter record. A Class A account should show a global adjustment amount that follows its peak demand factor, not a rate per kWh.
2. Which rate version did the bill use? For Class B accounts, divide the global adjustment charge by the kWh and compare with the IESO's first estimate, second estimate and actual for that month. A value that matches none of them needs a look.
3. Separate price from volume. A higher bill can be more kWh, a higher rate, or both. The review shows consumption and cost side by side so the reason is visible before anyone reacts. The monthly review report has a section for this.
4. Watch the demand. For accounts near the 1 MW threshold, or 500 kW in eligible sectors, the monthly peak demand decides whether Class A is an option next base period. The interval data heat map shows when the peak occurs; see interval data heat maps.
5. For Class A accounts, track the five peaks. The peak demand factor is set by the building's demand in five specific hours. If the operations team reduced load in those hours, the following year's factor should fall; if it did not, the factor explains the bill.
6. Reconcile against the tariff total. Global adjustment is one line among delivery, regulatory and HST lines. A bill validation step checks that the lines add to the amount due and that the reporting month is right.

Where it fits in the review

Global adjustment is a cost driver, not an energy driver. A building can use less electricity and pay more, or the reverse. The monthly review keeps the two apart: consumption and weather-adjusted performance in one section, unit cost and its components in another. That separation is what lets a board or an owner see whether a cost increase is something the building can do anything about. The utility cost benchmarking article covers how to compare cost across buildings once price effects are isolated.

FAQ

Can a building reduce its global adjustment?

A Class B building reduces it only by using fewer kWh. A Class A building reduces its share by lowering demand during the province's five peak hours, which is the point of the ICI. The review shows which case applies and, for Class A, when the peaks fell.

Why did our cost per kWh change when our contract did not?

Because the Class B rate is set each month and the bill may carry an estimate. Comparing the bill's implied rate with the IESO's published values for that month usually explains it. If it does not, the bill deserves a query to the utility.

Does VE-MAP change which class we are in?

No. Class A participation is a decision the customer makes with its utility under the IESO's rules. VE-MAP records the class per account, checks the charge against it, and gives the demand history that informs the decision. Request a review to see it on your accounts.