Here's an article from the National Post about the cancellations and at the end, mentions the problems of Ontario producing too much power, but guaranteeing prices to renewables:
The Independent Electricity System Operator said two weeks ago that “more than 3,000 megawatts (MW) of capacity will be added to the grid” over the next 18 months. Half of that will be renewables, which by early 2014 will bring the total of wind and solar capacity in the system to 4,800 MW. But the IESO also said that total energy consumption is “forecast to remain flat in 2012 before shrinking slightly in 2013,” due to a weaker provincial economy, conservation initiatives and other factors.
he province pays $135 per megawatt of wind energy, as mandated by the Green Energy Act.
Watch for high global adjustment charges on your hydro bill in the fall.