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Rates - For Business

Electricity Rates & Charges Glossary of Electricity Terms Understanding Your Bill

Home Accounts & Billing Rates For Business

Ontario Electricity Market Price

Electricity prices are influenced by supply and demand across the province. Businesses with a peak demand of 50 kilowatts or more are charged the wholesale market price for electricity.

This wholesale price is set through a market administered by the Independent Electricity System Operator (IESO). The IESO determines the Ontario Electricity Market Price (OEMP), which applies to large consumers and local distribution companies, such as GrandBridge Energy. These costs are then passed on to customers who are billed at market rates.

The price customers pay is based on the IESO’s day-ahead market (DAM). It includes the Ontario Zonal Price (OZP), an hourly, province-wide rate, along with the Load Forecast Deviation Adjustment (LFDA), which accounts for differences between forecasted electricity demand and actual usage in real time.

Learn More About Ontario's Wholesale Electricity Market

Small Business Electricity Rates

Small commercial customers are not billed based on Ontario’s wholesale market pricing. Instead, their electricity rates are set by the Ontario Energy Board and are designed to provide stable and predictable pricing.

Depending on their eligibility, small businesses may be billed under Time-of-Use, Tiered or Ultra-Low Overnight (ULO) rate plans.

These rates are based on a 12-month forecast of electricity supply and demand, helping to balance affordability for customers with the cost of generating electricity. As a business customer, your bill is made up of four main components: electricity generation, delivery, regulatory charges and taxes.

Learn More About TOU, Tiered & ULO Rates

Electricity Rates and Charges for Business Customers

Previous Business Rates

Electricity rates and charges for business customers prior to January 1, 2026.

Electricity Rate Information

This is the cost of electricity supplied during the billing period and is calculated on the adjusted kilowatt hours (kWh) used. The electricity charges on your bill will be based on prices set by spot market pricing through the Independent Electricity System Operator (IESO) and the Ontario Energy Board or based on a contract with a retailer. Electricity charges are collected by GrandBridge Energy and paid directly to electricity suppliers. We do not keep any of these charges.

On May 1, 2025, the Independent Electricity System Operator (IESO) launched the Market Renewal Program (MRP) to modernize Ontario’s electricity market to make it more efficient, transparent, and reliable.

GrandBridge Energy’s large commercial, industrial, and institutional customers will pay a market price for the electricity supply referred to as the Ontario Electricity Market Price (OEMP), previously the Hourly Ontario Energy Price.  The only change to this market price is the process used behind the scenes to calculate the market price.

More information is available from the IESO:

 

Small business customers who use <50 kWh monthly are automatically part of the Regulated Price Plan (RPP) for the purchase of electricity. This means you are charged a regulated price per kilowatt hour (kWh) for electricity you use. RPP customers are classified as Standard Supply Service customers. The rates include Global Adjustment Charges. The Ontario Energy Board reviews these electricity rates every six months in May and November.

You can choose between three electricity price plan options: Time-of-Use (TOU), Ultra-Low Overnight (ULO) or Tiered. You can switch between these options anytime, but you must notify GrandBridge Energy through your My Account portal or by submitting an election form.

  • Time-of-use (TOU): With TOU prices, the price depends on when you use electricity. You can help manage your electricity costs by shifting your usage to lower price periods.There are three TOU periods:
    • Off-peak: When electricity demand is lowest. Ontario households use most of their electricity – nearly two-thirds of it – during off-peak hours.
    • Mid-peak: When electricity demand is moderate. These periods are during the daytime but not the busiest times of the day.
    • On-peak: When electricity demand is generally higher. These are the busier times of day – typically when people cook, start their computers, and run heaters or air conditioners.

    People use electricity differently depending on the season, so the TOU price periods are different in winter than summer.

  • Ultra-Low Overnight (ULO):With Ultra-Low Overnight (ULO) prices, customers are charged according to the day of the week and time they use electricity. This plan benefits customers who consume most of their electricity overnight or charge an electric vehicle overnight. The ULO periods are the same in the summer as in the winter.There are four different ULO price periods.
    • ULO Overnight – when electricity demand is lowest on average.
    • ULO Weekend Off-peak – when electricity demand is generally lower.
    • ULO Mid-peak – when electricity demand is moderate.
    • ULO On-peak – when electricity demand is highest on average.
  • Tiered: With Tiered prices, you can use electricity throughout the day/week at the same price (tier 1) if you do not exceed the allotted threshold (per kWh). Once that limit is exceeded, a higher price (tier 2) applies. For small commercial customers, the threshold is 750 kWh all year round.
Complete the Regulated Price Plan Election Form

Customers also have the option to purchase electricity from an electricity Retailer. If a consumer signs a retail contract, they pay a fixed rate independent of the RPP pricing and Spot Market price. These customers will also pay the Global Adjustment in addition to the rate of their retail contract.

Glossary of Electricity Terms

The Electricity charges on your bill are based on the prices set by the Ontario Energy Board or a contract with a Retailer. Electricity charges are collected by the utility and paid directly to electricity suppliers.

The delivery charge is the cost of delivering electricity from generation stations across the province to GrandBridge Energy and then to your business. This includes the costs of building and maintaining the transmission and distribution lines, towers, and poles and operating provincial and local electricity systems.

A portion of these charges are fixed and do not change from month to month. The rest are variable and increase or decrease depending on your electricity use.

GrandBridge Energy retains only the Monthly Service Charge and the Local Distribution charge (called the Delivery) on your bill.

Regulatory charges are the costs of administering the wholesale electricity system and maintaining the reliability of the provincial grid.

Electricity generators in Ontario receive a combination of payments from the operation of the wholesale market, payments set by regulation and payments set by contracts. Your portion of the net adjustments arising from these and other authorized payments is included on your bill as Global Adjustment.

Understanding Your Bill

Understanding your GrandBridge Energy bill is key to managing your electricity use and avoiding surprises. Knowing how charges are calculated, including the difference between winter and summer thresholds, delivery fees, and rate options—can help you make informed decisions and better control your costs. Visit our Understanding Your Bill page to explore the features and charges that make up your bill. Because when it comes to your energy use, knowledge is power.

Learn How to Understand Your Bill