Global Adjustment in Ontario – Plain English Guide
Updated 2026‑04‑22
The Global Adjustment (GA) is one of the most confusing parts of an Ontario electricity bill. It does not behave like a simple “you used X, so you pay Y” charge. Instead, GA recovers long‑term system costs that keep Ontario’s electricity grid reliable. This guide explains what GA is, why it exists, and how it affects your bill — in plain English.
What the Global Adjustment pays for
According to the Independent Electricity System Operator (IESO), the Global Adjustment covers the cost of:
- building new electricity infrastructure
- maintaining and refurbishing existing generation resources
- long‑term contracts with generators
- regulated nuclear and hydro generation
- conservation and demand‑management programs
These costs ensure Ontario has enough electricity supply over the long term, regardless of short‑term market fluctuations.
Why GA exists
Ontario’s electricity system includes many assets whose costs do not move up and down with your household’s monthly usage. Nuclear refurbishments, hydroelectric stations, long‑term renewable contracts, and reliability programs all require stable funding.
GA is the mechanism that ensures these costs are recovered fairly across the province.
How GA is calculated
GA represents the difference between:
- what generators are paid under contracts or regulated rates, and
- what the market earns through the Hourly Ontario Energy Price (HOEP)
When the wholesale market price is low, GA tends to be higher. When the market price is high, GA tends to be lower. This inverse relationship is confirmed by the IESO.
In other words, GA smooths out the cost of electricity supply over time.
Who pays the Global Adjustment?
All Ontario electricity customers pay GA, but the way it appears on bills differs:
- Residential and small business customers (Class B): GA is built into Time‑of‑Use and Tiered rates set by the Ontario Energy Board.
- Medium and large customers (Class B wholesale metered): GA appears as a separate line item.
- Large industrial customers (Class A): GA is based on their contribution to the top five peak hours of the year (the Industrial Conservation Initiative).
Most households never see GA listed separately because it is already included in their regulated electricity price.
Why GA fluctuates month to month
GA changes for several reasons:
- Market price changes: When HOEP drops, GA rises to cover the gap.
- Contracted generator output: Some generators are paid fixed or regulated rates regardless of market conditions.
- Seasonal demand: Summer and winter peaks affect system costs.
- Conservation program costs: These are included in GA.
Because GA reflects system‑wide factors, it does not track your personal electricity usage closely.
Common misconceptions about GA
“GA is a penalty.”
GA is not a penalty. It is a cost‑recovery mechanism for long‑term system investments.
“If I use less electricity, GA should drop proportionally.”
Some parts of your bill behave this way, but GA does not. It reflects system‑level costs, not just your usage.
“My utility controls GA.”
Utilities bill GA, but they do not set it. GA is shaped by provincial policy, contracts, and market conditions.
GA for Class A customers (Industrial Conservation Initiative)
Large electricity users can reduce their GA costs by lowering consumption during the top five peak hours of the year. Their GA charge is based on their Peak Demand Factor (PDF).
This program does not apply to residential customers.
Why GA matters for households
Even though GA is included in regulated rates, it still affects your total bill. GA is one of the reasons electricity prices do not always fall when wholesale prices drop — long‑term system costs remain constant.
Understanding GA helps explain why bills behave the way they do, especially during low‑usage months.
What you can control
You cannot directly control GA, but you can influence the parts of your bill that respond to usage:
- Choose the pricing plan (TOU, Tiered, ULO) that matches your habits.
- Shift heavy loads (laundry, EV charging) to off‑peak periods.
- Check for estimated meter readings.
- Review your historical usage patterns.
These steps often have a bigger impact on your bill than trying to “chase” GA.