Ontario's Independent Electricity System Operator said electric supplies should be adequate under normal weather conditions through the summer 2018 peak but warned that if extreme temperatures materialize it may reject some planned generator maintenance outages in the next two summers.
The province's grid operator, known as IESO, expects demand to rise in this year's summer peak season amid increased economic and population growth. Expansion of embedded generation within the grid and a broader industrial conservation program will not offset the growth, according to its latest 18-month power supply outlook.
Peak summer power demand is expected to be 22,614 MW under normal circumstances in 2017, while extreme weather could push that to 24,902 MW, IESO said. Demand is expected to ebb slightly in the summer of 2018, with a peak draw of 22,550 MW under normal conditions and 24,731 MW in extreme weather. Winter demand for the 2017-2018 season will see a normal demand peak of 21,859 MW and 23,067 MW in extreme weather.
"Under extreme weather conditions, the reserve levels which reflect current planned generator outages are below requirement for a combined total of 25 weeks over the summer periods in 2017 and 2018," IESO said in the outlook. "If extreme weather conditions materialize, the IESO may need to reject some generator maintenance outages to ensure that Ontario demand is met during the summer peak. Therefore, generators expecting to perform maintenance during the summer should understand that those outages are at risk and are advised to review their maintenance plans and consider rescheduling them."
Refurbishment of Ontario's nuclear plants will affect the grid throughout the forecast period. Ontario Power Generation Inc. and Bruce Power LP have been given the go-ahead to rebuild their plants to extend the operating lives of the facilities.
Ontario will see about 1,950 MW of new supply added to the grid over the forecast period. New sources include 1,300 MW of gas-fired generation, 500 MW of wind, 100 MW of solar and 50 MW of hydroelectric power. By the end of the forecast period IESO expects to have about 4,500 MW of wind power connected to the grid and 380 MW of solar generation. Embedded solar generation within Ontario is expected to climb to more than 2,200 MW, and embedded wind power will exceed 600 MW.
IESO warned that a partial solar eclipse will occur in the province Aug. 21, 2017, diminishing solar generation and boosting demand for power from the grid.