Ontario Electricity Explained Ontario • Electricity

Ontario Electricity Ultimate Guide

A complete, plain‑English overview of how Ontario’s electricity system works — from generation to billing — and what residents can do to manage costs.

Updated 2026‑04‑22

Contents

1. The big picture: how Ontario’s electricity system works

Ontario’s electricity system is built around a simple idea: electricity must be produced, moved, and delivered the instant you need it. Unlike water or natural gas, electricity cannot be stored easily at large scale, so the system must constantly balance supply and demand.

Ontario’s system has four major layers:

  • Generation — power plants produce electricity.
  • Transmission — high‑voltage lines move electricity across the province.
  • Distribution — local utilities deliver electricity to homes and businesses.
  • Market and regulation — organizations set rules, run the market, and ensure reliability.

Each layer adds cost, which is why your bill includes more than just the price of electricity itself.

2. Who runs the system? Key organizations and their roles

Ontario’s electricity system is managed by several organizations, each with a specific role:

Independent Electricity System Operator (IESO)

The IESO balances supply and demand in real time, operates the wholesale market, and plans for future electricity needs. It ensures the grid remains stable every second of the day.

Ontario Energy Board (OEB)

The OEB regulates electricity rates, approves utility budgets, and sets rules for billing and consumer protection. It determines TOU, Tiered, and ULO prices.

Hydro One and other transmitters

Hydro One operates most of Ontario’s high‑voltage transmission system. A few smaller transmitters operate regional networks.

Local distribution companies (LDCs)

These utilities deliver electricity to homes and businesses. Examples include Alectra, Toronto Hydro, Elexicon, Hydro Ottawa, and Hydro One.

3. How electricity pricing is set in Ontario

Electricity pricing in Ontario is shaped by three major components:

  • Market price (HOEP) — the wholesale price of electricity.
  • Contracted and regulated costs — long‑term contracts and regulated generation.
  • System costs — reliability programs, planning, and infrastructure.

Residential customers do not pay the wholesale market price directly. Instead, the OEB sets regulated rates (TOU, Tiered, ULO) that include both the market price and the Global Adjustment.

4. What actually appears on your bill

Your electricity bill includes several components. For a full breakdown, see How Ontario Electricity Billing Works. At a high level, your bill includes:

  • Electricity/energy charge — based on your pricing plan.
  • Delivery charges — cost of transmission and distribution.
  • Regulatory charges — system‑wide programs and market operations.
  • Global Adjustment — included in regulated rates.
  • HST
  • Ontario Electricity Rebate (OER)

Each component reflects a different part of the system. Delivery charges, for example, pay for poles, wires, transformers, and maintenance — not electricity itself.

5. TOU vs Tiered vs ULO — choosing the right plan

Ontario households can choose between three pricing structures:

  • Time‑of‑Use (TOU) — price varies by time of day.
  • Tiered — one rate up to a threshold, another above it.
  • Ultra‑Low Overnight (ULO) — very low overnight rate.

Each plan works best for different usage patterns. You can compare them using:

Choosing the right plan can meaningfully reduce your bill, especially if you can shift flexible loads like laundry, dishwashing, or EV charging.

6. Smart meters, peak periods, and how usage is measured

Ontario uses smart meters for all residential customers. These meters record electricity usage in hourly intervals and send data to your utility automatically.

Smart meters enable:

  • Time‑of‑Use billing
  • Ultra‑Low Overnight billing
  • Detailed usage charts on utility portals
  • Faster outage detection

Understanding your hourly usage can help you identify patterns — for example, whether your home has high overnight baseload usage or large spikes during peak periods.

7. Why electricity costs change through the year

Even if your habits stay the same, your bill can change due to:

  • Seasonal heating and cooling
  • Rate updates (TOU, Tiered, ULO)
  • Delivery charge adjustments
  • Weather‑driven demand
  • Estimated vs actual readings

For a deeper explanation, see Why Your Bill Changed.

8. The future of Ontario’s electricity system

Ontario’s electricity system is entering a period of major change. Key trends include:

  • Growth in electric vehicles
  • Electrification of heating (heat pumps)
  • New nuclear projects and refurbishments
  • Expansion of energy storage
  • More renewable generation
  • Modernized market rules

These changes will influence future electricity prices and the structure of the system.

9. What actually lowers your bill

There are two main ways to reduce your electricity bill:

  • Use fewer kWh overall
  • Shift flexible usage to cheaper periods

Practical actions

  • Run laundry and dishwashers during off‑peak or overnight hours
  • Charge EVs overnight (ULO or TOU)
  • Reduce standby loads (electronics, chargers, old appliances)
  • Use programmable thermostats
  • Improve insulation and air sealing
  • Use heat pumps efficiently

For personalized estimates, try:

10. Frequently Asked Questions

Which plan is cheapest in Ontario?

It depends on your usage pattern. Off‑peak flexibility favours TOU or ULO. Steady usage favours Tiered.

Why are delivery charges so high?

Delivery charges pay for the infrastructure that brings electricity to your home — poles, wires, transformers, substations, and maintenance.

What is the Global Adjustment?

The Global Adjustment helps fund long‑term contracts, regulated generation, and system reliability programs.

Are these calculators exact?

No. They are educational tools. Actual bills depend on your utility’s delivery structure and current rates.