Chapter 4.8: Output vs Winter Temperature

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Winter is the opposite of the Summer, so we need to compare Wind’s Hourly Capacity Factor (HCF) with Winter’s minimum temperatures (TMin), which occurs at night.  All temperatures are from Station 4333, Ottawa Intl Airport, and is representative of Southern Ontario.  Some of the southerly lake side locations would have been more moderated, but only by 5 or so degrees.

The Winter of 2010 was milder for TMin than previous years:

2009 Winter was the coldest of the 4 years, compared to 2010 5C colder for TMin.  So 2009 (Dec 2008-Feb 2009) was chosen to compare demand and output from wind.

The temperature range for those months looks like this:

Notice the wind HCF is all over the map, right up to more than 95%.  You will recall that several of the locations, such as Port Alma, had a higher number of hours in the 90% range in the winter.  You will see how that is incorporated into the demand and temperatures in the next graph.

But first a much smaller date range is needed, so we will look at the 4 coldest days of the season, Jan 14 to 17, to see how the temperature, demand and HCF match up.

You can clearly see the how each farm performed during the very cold nights (Wolfe Island wasn’t up and running then).   Port Alma for example, had increasing spikes of HCF during the night-time (which means the wind was blowing making the windchill factor much less than the -30C in Ottawa).  However nice that looks, it is dampened by the fact that demand during those hours drops dramatically in every case. 

By the 15th of Jan it appears a “warm” front passes through, providing wind a reasonable performance (the 18th had a nighttime max of -15C).  But notice the demand drops off too.  This begs the question, which power suppliers, when wind was not blowing (Jan 14 -16), who provide for that higher demand was turned off when wind started to blow Jan 17-18?  Some one must have been throttled back in favour of wind (and likely both paid, but that is another story).

What one can take from this is that wind blows at night more so than the day time during the winter, which corresponds to the coldest time of day (hence more heating required).  However the 35% drop in demand during those hours makes wind unnecessary.

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