Ontario Electricity Policy - Conservation and Demand Management

Conservation and Demand Management

Electricity use can be divided into three main sectors:

• Residential sector: this includes residential space and water heating and cooling, lighting, household appliances, etc. Electricity use in this sector accounts for about one third of total consumption in Ontario. Residential demand is projected to decline slightly.
• Commercial sector: this includes mainly space heating, and cooling, as well as commercial and office lighting. This sector accounts for about 39% of Ontario's total electricity consumption and is projected to grow the most.
• Industrial sector: this includes manufacturing activities, mining activities, forestry and construction. Industrial consumers account for approximately 28% of electricity consumed in Ontario. This consumption is projected to remain stable.

Electricity demand can also be separated as base load and peak demand. Base load refers to constant, or unvarying, demand for electricity. In Ontario, base load amounts to approximately 13,000 MW and is met by nuclear and hydroelectric power. These supply options generally have low operating costs and are unable to rapidly change their output.

Peak demand refers to fluctuating, or varying, needs for electricity above and beyond base load levels. Added to this base load, the peak load raises Ontario's maximum electricity demand to 27,000 MW. This peak is typically met by oil/natural gas-fired, coal and select hydro-electric power plants. These plants can respond to changes in demand rapidly, but have higher operating costs.

Average demand in Ontario is currently 17,500 MW.

Electricity demand is greatly affected by seasonal variations. A recent trend has developed whereby summer peak demand has grown to outpace winter peak loads. This is primarily the result of increasingly warm summer conditions. The highest load recorded in Ontario occurred on 1 August 2006, when peak demand for electricity reached 27,005 MW. The highest winter peak demand occurred 13 February 2007, when peak demand was 25,868 MW.

Peak demand also varies by the time of day. The daily peak period refers to the time of the day when demand is at its high. In winter, there are generally two peaking periods: around 10:30 a.m. in the morning and around 6 p.m. in the evening. In summer months, demand peaks in the late afternoon, when temperatures are at their hottest.