Peak Shaving

Toronto Hydro had an interesting program for shaving peak usage last summer.  They issued wireless devices that could be installed on your home air conditioner, to cut your air conditioner when the system had especially high demand.  (It
If the air conditioner is cut for 15 minutes out of every half hour, you will hardly notice it.  But it can make a real difference to the level of the system peak.

Last August, the Ontario system had an all time peak during a hot spell.  (Writing about a hot spell when it is minus 13, windy, and snowing, seems to be especially easy to do.)  Toronto Hydro had implemented their Peak Saver program to cut the peaks from air conditioners.  While Ontario’s peak was higher than the previous system peak by 4%, or 845 MW, Toronto’s peak was 5 MW below their previous peak.  While not all of this may be attributed to the Peak Saver program, it is clear that something is going on here.

The implications of effective peak shaving are profound.  It can allow the system to avoid transmission upgrades.  The OPA has proposed significant transmission upgrades for Toronto, with all the controversy and cost it entails.  And it avoids the spending in new generation capacity to handle system peaks.  One study shows that the cost of supplying power during the top .1% of the system peaks, or 87 hours per year, is $1.39/kWh.  This compares with the delivered cost of power of about 10 cents/kWh that is normally charged.   So can we spend money to trim system peaks?  You bet.  We can spend lots.

Toronto Hydro was the only local distribution company to offer the Peak Saver program that I am aware of.  And of course such a program would be more effective, and more cost effective in cities, as wireless is easier to implement in dense living quarters, and air conditioning load is higher in cities, as they are warmer than the country.  But Hamilton, London, Windsor, Kitchener, Guelph, Brampton, Oshawa and other cities would seem like natural targets for such peak saving programs.

Peak shaving does not reduce the emissions from the electricity system very much.  But it can save a lot of money.  And it can build system flexibility, which is useful in integrating renewable energy.

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