August 30, 2022

Managing Energy Supply and Demand in Ontario

As discussed in “Ontario Energy Resources”, Ontario has several energy sources that power the province’s electricity system. As no single source of energy can always meet the needs of the system, these resources work together to balance electricity supply and demand.

Managing Energy Supply and Demand in Ontario

Managing Supply

As the demand for energy fluctuates throughout the day, each power generator plays a different role in supplying this energy.

Baseload generation

Nuclear power plants and “run-of-the-river” hydro facilities are baseload generators, providing steady electricity output 24 hours a day. These are facilities with little or no storage capabilities. In some cases, these generators may be able to adjust their output, but only to a limited degree. This generally occurs when total electricity demand is forecasted to be less than usual.

Peaking and intermediate generation

Natural gas facilities and hydroelectric generators with storage capabilities can increase or decrease their output based on demand. Some act as intermediate generation, working throughout the day to adjust their output based on fluctuations in consumer demand. They can also act as backup if another generator suddenly fails and is unable to produce power.

Variable but controllable generation

Solar and wind generators are considered variable as their output is based on variations in the sun and wind. For larger solar and wind facilities (those greater than 5MW), the IESO uses meteorological data, plus operational information to forecast the amount of energy to be provided hourly. These facilities are connected to the IESO-controlled grid and can increase or decrease their output based on instructions from the IESO.

Distribution-connected (embedded) generation

Embedded generators supply electricity to local distribution systems, reducing demand on the transmission grid. Solar power provides the largest amount of embedded generation, followed by wind and water. The energy output for these resources is less predictable, which can create operational challenges for the IESO compared to other forms of generation. However, it can improve the efficiency of electricity delivery and reduce costs.

Managing Demand

Managing electricity demand means not only predicting future generation requirements, but also recognizes the least expensive alternative is energy efficiency.

Energy efficiency

The IESO is committed to providing Ontario residential and business electricity users with educational resources and programs to help them better manage their energy use. The “2021 – 2024 Conservation and Demand Management Framework” is expected to help the province achieve 440 MW of peak demand savings and 2.7 TWh of electricity savings over the program’s four-year timeframe.

Electricity imports and exports

Ontario’s electricity grid is part of a North American network that is interconnected with five neighbours – Quebec, Manitoba, Minnesota, Michigan, and New York. The constant import and export of energy allows the IESO to maintain balance of the electricity system, as well as increase reliability and cost-effectiveness.

Demand response

Demand response allows consumers to reduce their electricity use in response to system needs and prices. The IESO’s Capacity Auction (formerly Demand Response Auction) allows large electricity consumers and aggregators of smaller institutional, commercial, and industrial customers, to compete to electricity capacity when the demand is high to avoid power outages.

Energy Storage

Energy storage allows electricity to be captured, stored, and released back into the power grid when it is needed. This can help even out energy fluctuations of variable resources, such as solar and wind, and absorb surplus baseload generation such as nuclear and run-of-the-river when the output is higher than minimum demands. The IESO continues to investigate how energy storage technologies can be integrated into the power system and is using storage to regulate balance on the grid.

Source: Independent Electricity System Operator (IESO)