This post is a "re-blog" of sorts, as it is co-written with Parker Gallant, and has been posted to the Energy Probe site. There's a couple of edits here, and I've included footnotes to support a number of the statements
The first 7 days of 2014 ended with an average market price higher than it had been in years. On January 2nd prices were sent upwards as neighbouring Quebec appealed for conservation during bitter cold which sent demand to near record levels.
When “total” demand, which includes exports, peaked at 25,980 MW at 7 pm of the 7th day, Ontario’s system operator indicated generation on it’s grid was greater than it had ever been; strong nuclear, hydro and wind output was supplemented by record output from Ontario’s natural gas generators.
The Hourly Ontario Energy Price (HOEP) was a high $278.93/MWh, but it wasn’t due to Ontario’s demand stressing supply. The key price drivers were coming from the grids connected to Ontario’s.
As demand peaked on the 7th, exports averaged 3,187MW with multiple U.S. jurisdictions hitting winter demand records due to the cold impact of what is being called a polar vortex. This made January 7th a record day for revenue on net exports, with 62 GWh valued at approximately $7.3 million dollars (~$117/MWh). 
How profitable those exports were for Ontario entities is a matter of opinion. The same day saw record production of over 44 GWh from industrial wind turbines in Ontario. That production, even when fetching an average price of $111.41/MWh, wouldn’t make any profit.
However, export customers were buying whatever kilowatts (kWh) were available on the 7th. Those kWh were not coming from the “must take” producers (primarily nuclear, wind and solar), but generators which exist because every month each Ontario ratepayer finances the Net Revenue Requirement (NRR) contracts required to keep their capacity available. The incremental cost of this supply, (the fuel cost) was likely close to $40/MWh on the 7th making exporting profitable. 
Profiting on exports is a welcome change for the province, which, by one accounting, lost over $1 billion on exports in 2013: 18.3 million megawatt-hours were exported in 2013 without recovering the $59/MWh global adjustment (Class B) charge that is collected from most Ontario ratepayers.
A couple of million dollars profit on a day of unusual high demand is not significant compared to the capital and operational cost Ontarians pay due to NRR contracts, including OPG’s Lennox Generating Station, Ontario has contracts for approximately 6,700 MW of gas/oilfired generating capacity with a base cost of around $1 billion a year. $7 million of revenue from an exceptional export demand day does not go very far to paying for this capacity.
Ontarians have reason to be concerned about subsidizing gas and oil fueled generation for export.
The day after Ontario had record wind production and revenue on net exports, its government issued yet another news release on ending coalfired generation in the province, promising “a significant reduction in harmful emissions, cleaner air and a healthier environment.” While the goals are noble, treating coal as bad and gas as clean is extraordinarily simplistic. Consecutive Premiers (McGuinty and Wynne) of the province have tacitly acknowledged this in submitting to worries of residents in Mississauga, and Oakville, and cancelling contracted generation in that fragile region of Ontario’s grid at a cost of over $1 billion.
It may perplex residents near the Halton Hills Plant in Milton, Brampton’s Goreway, and Toronto’s Portlands power stations that their local generators run any time a nickel can be made on exports, while the Liberal Premiers were certain Oakville and Mississauga are definitely the wrong place, at any price, for electricity to be generated from burning natural gas, due to real, or imagined, health impacts.
Ratepayers throughout the province should question why, following a day of record generation exported far and wide, Ontario is set to add 3,300MW of intermittent wind and solar generation during the next 18 months , all of it contracted at rates higher than we averaged on the most profitable day of exporting in the market’s history.
Ontario can't count on a daily 20-year weather event such as a “polar vortex” to generate profits on exports that might help to mitigate the continuing price increases in their electricity bills.
Scott Luft and Parker Gallant
1. Week 28 of 2010 is the last of only 3 weeks since 2010 that had weekly average Hourly Ontario Energy Price averaging above 2014 week 1’s $55.56/MWh.
2. The system operator (IESO) reports the sum of all generation + imports, as “Total Market Demand” in its “Hourly Demands” file, and the reporting flowing from that data file. Calculating Ontario supply on the grid simply requires imports to be subtracted from “total market demand”, and at hour 19 of January 7th, that figure is 25,929MW - a new high.
3. This statement is based on production from all “gas” generators in the IESO’s Hourly Generator Output & Capability Report, as well as the oil/gas Lennox Generating Station. Record of 6,962 MW was set in hour 19.
5. The U.S.A.'s Federal Energy Regulatory Commission produced an initial report, Recent Weather Impacts on the Bulk Power System. It states; "Many system operators in the Eastern United States broke their winter peak demand records. MISO, SPP, ERCOT, PJM, and the New York ISO all set winter peak demand records, as did most of the utilities in the Southeast."
6. Valued as hourly exports less hourly imports, multiplied by the Hourly Ontario Energy Price (HOEP). The second highest revenue day on net exports is now January 8, 2014; valued at HOEP it's a distand $4.85 million - slightly above January 23rd, 2013
7. Net Revenue Requirement (NRR) contacts are reportedly structured so that most of the profits on market sales would benefit Ontario ratepayers; "the contracts stipulate that 95 per cent of the surplus will flow back to ratepayers."
8. Figure is from IESO 18-Month Outlook: From December 2013 to May 2015