◊ Part of the ‘wind energy’ series of articles ◊
Wind energy is an intermittent source. System operators cannot depend on its availability when the electrical load requires it. Wind patterns can be forecasted reasonably well the day ahead, however longer forecasting brings greater uncertainty and higher risk to grid security should it not materialize. It does not provide energy on demand, it provides energy when the wind and weather conditions permit.
For these reason, the grid requires a different energy source as a backup for wind. A source which is available on demand. Like natural gas. Under the right circumstances, other sources including hydro can be used to back up wind, however most wind energy debates focus on natural gas sources as the alternative.
The planning authority in Ontario (the IESO) is accountable for determining the extent to which intermittent energy requires backup, however there is no escaping operational constraints, regulatory requirements and political influence. When you apply all of these considerations you get the status quo which will not make sense without an extensive knowledge of the drivers and events that predicated it. I have no intention of untangling that mess, however it has determined our present state and what the generation mix will be for the next decade.
In an ECO report, the 2016 estimated cost of gas generation was the same as for wind at 16 cents/kWh. I have to presume that includes all of the contractual compensation terms afforded to gas generators whether they run or not.
If the planning authority sized the system so that all of the wind generation capacity was backed up by natural gas resources the economic unit-cost for the energy volume would be almost twice the price of wind energy with split utilization between the two resources. The reason for such a high cost is that generators are compensated whether they produce energy or not. I have seen references to the guideline of backing-up 90% of wind energy by alternative sources (OSPE) which can be made available on demand (i.e. natural gas generation).
The Toronto area 875 MW natural gas plant Sithe-Goreway had a Capacity Factor of 10% based on IESO generator output data for 2018. That’s typical of all natural gas generation in Ontario.
There is a total of 9,400 MW of natural gas generation in Ontario that is owned by Independent Power Producers that make money whether they produce energy or not. The total natural gas based generation in Ontario had an 11% Capacity Factor for 2018.
There is almost twice as much natural gas generation capacity in Ontario as wind. It produces energy less than half as often as wind. Even if natural gas generation were to completely displace wind, the Capacity Factor would only go up to 23%. That’s a large investment for idle capacity. Even more than wind.
To be fair, the capacity and capacity factors of natural gas generators are not the best measures to reflect the value of generation which can be made available on-demand.
The takeaway
It appears that we have way more natural gas generation capacity in Ontario than we require to back up wind. It is in place for other reasons.
The cost of natural gas generation to back up wind in Ontario may not be at the level suggested by independent studies.
The economic cost of wind in Ontario must include some portion of the installed gas capacity, but not as much as 90%.
Derek
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Natural gas backs up Nuclear power.
Natural gas capacity factor is very low due to the abundance of nuclear power (currently operating at peak capacity prior to the refit).
Ontario energy rules require the large scale nuclear fleet have back up especially during the upcoming $20B refit program and decommissioning of Pickering in a few years time.
Natural gas was scaled up dramatically in the past decade to cover the refit as top priority.
The wind power in Ontario is a small fraction of the nuclear power output, and the following site shows the dynamic quite clearly if you monitor it regularly as I do:
http://www.ieso.ca/power-data#supply
Very typically the balance of water based hydro production in Ontario is the compensating variable load that increases and decreases to cover for wind variability.
All this to say, wind is one of the cheapest ways to add *new* power to the Ontario grid.
Whereas solar PV on the rooftops of homes is even better due to very low infrastructure cost (no transmission required, no additional large scale facility upgrades required).
Thanks for your input Glenn!