Curtailment of industrial wind turbine production in Ontario soars in 2015

A 2015 year-end review of my hourly estimates indicate the curtailment of output from industrial wind turbines (IWTs) soared in 2015. I show total curtailment exceeding 1 million megawatt-hours, which I assume Ontario ratepayers paid ~$127 million for regardless.

I show the potential supply curtailed rising to 10% from 6%.



The increase in curtailment in the Bruce region is galling as an examination of output from one IWT location there revealed that during the peak electricity demand of summer it was often a net consumer of grid power rather than a contributor to supply.

Note in the above graphic that only the Northwest breaks a trend that sees higher curtailment equate to lower market valuation of the output of the zones’ IWTs, with a doubling of curtailment in the Bruce region matched by a halving of market value of production.

The increase in curtailment in 2015 is particularly relevant because the Large Renewable Procurement which the IESO (operator of the system) intends to proceed with in 2016 used about 6% as the level of curtailment it anticipated. If more IWTs are added, they’ll be increasingly wrong. In 2015 potential output from IWT’s could have increased by about 2,500 gigawatt-hours (GWh), while I estimate curtailment increased by about 575 GWh – which indicates 22% of new supply ended in curtailment of wind.

There are other reasons curtailment would change, particularly in 2016. Up until January 1, 2016 flexible nuclear at Bruce Power was dispatched previous to IWTs, but the rules have now been rationalized. We may look back at 1 million MWh of wind curtailment as the good ol’ days.

On the other hand, new locations seem to be more heavily curtailed initially – and that could be a function of forecasting accuracy growing (as curtailment estimates are based on forecasts).

Here’s a look at my estimated percentage of curtailment for each IWT location the IESO reports on.


Addendum (Jan. 7)

I revisited the data to build the following chart, which provides a demonstration of the declining value of variable intermittent generation as it grows in market penetration.

image (47).png

I wrote on this in The Real High Price of Low-Value Electricity, but suggest Lion Hirth’s work as the best presentation of why this relationship must be, particularly The Market Value of Variable Renewables: The Effect of Solar and Wind Power Variability on their Relative Price


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