Toronto: Negative hourly prices, which had previously been primarily restricted to the shoulder months, have been cropping up even during the highest demand months of the year. There were 17 instances where the HOEP was less than $0 during the month of August. The lowest HOEP for the month was -$128.64 set on August 29, hour ending 1. The IESO noted that “A combination of low demand and ample generation availability resulted in the low price.” The lowest 5-minute interval price of -$129.10 was also set during August 29, hour ending 1, interval 12. The lowest hourly market demand of 12,900 MW was set on August 29, hour ending 3. There were six instances where the Hourly Ontario Energy Price (HOEP) was less than $0 during the month of September. So far in 2011 there have been 135 hours with a negative HOEP.
The IESO publishes a monthly synopsis of any pricing events (HOEP greater than $200 or less than $0) at the beginning of each month. The IESO also publishes daily, weekly and monthly market summaries.