In an earlier post, Emissions Savings Details, down in the “And Worser” section, I mentioned that between the not-entirely-dispatchable CHP plants and the entirely-not-dispatchable wind projects, Ontario has so much surplus generation at night that they end up paying other people to take it off their hands. This is called Surplus Baseload Generation, and as the number of CHP and wind generators continues to grow in Ontario’s attempt to shut down its last coal generators, it is becoming more common. Ontario’s IESO, the grid operator, now publishes a daily report that forecasts how big these surpluses will be. Take a look at a recent report – these numbers are BIG, and they seem to occur almost every night, at least during low-usage times of the year.
Here’s a link that should point you to the IESO’s latest estimate. If you’d like some additional details on the operation of Ontario’s grid (and I’m sure it mirrors many other grids) Donald Jones, a professional engineer who retired from the nuclear energy field, wrote up a nice explanation that isn’t too hard to follow.