Controlling the flow of wind power onto Ontario’s electricity grid could save consumers up to $225 million a year, says the province’s electricity system operator.
And it warns that with thousands of megawatts of new wind power due to flow onto the grid over the next few years, the problem will only more acute if rules are changed.
On windy days, Ontario is sometimes stuck with surplus power, as supply exceeds demand.
And that’s a problem the “simply must be tackled,” David Butters, the head of the Association of Power Producers of Ontario, agrees.
The figure for the potential cost of surplus wind power is contained in a presentation by the Independent Electricity System Operator.
Surplus power builds up when “baseload” power – power that runs all the time, or power that can’t be controlled – exceeds demand.
Baseload power is the output from nuclear power plants and big hydro stations that are designed to run all day, every day.
It’s technically difficult, or very expensive, to reduce the output from these plants.
At the same time, Ontario is rapidly building wind farms, whose output flows onto the system whenever the wind blows.
Sometimes, when the wind blows strongly and demand is low, there’s more power flowing onto Ontario’s grid than the province can handle.
Ontario has sometimes been forced to pay neighbouring states or provinces to take surplus power off its hands.
The problem is likely to get worse, the IESO says in a presentation released Tuesday.
Today, the province at most gets about 1,600 megawatts of wind-generated power on a windy day.
By 2017, however, the province could be producing as much as 7,600 megawatts of wind power, resulting in occasional surpluses of up to 6,500 megawatts if solutions aren’t found.
That’s more than enough electricity to power the entire City of Toronto on a hot day, with air conditioners running full blast.
If wind isn’t controlled, other generators would have to cut back.
How much? Well, in theory, the IESO says curbing the surplus would require taking as many as nine nuclear reactors offline – or about half the province nuclear units in the province.
That’s “unacceptable,” says the IESO, because nuclear units can’t be flicked on and off quickly.
Once shut down, reactors can take several days to gear back up. Forcing them to shut down to deal with a surplus of a few hours could leave the province unable to use the reactors for several days.
Controlling the flow of wind power onto the grid – even if wind generators get paid for power that doesn’t get used – is a cheaper solution than trying to control the output of nuclear plants, says the IESO presentation.
By 2014, the savings of controlling wind will be $180 million to $225 million, the IESO estimates.
Alexandra Campbell of the IESO said the system operator and the province’s electricity market participants are working on detailed rules of how wind power can be controlled, and proposals may be ready soon.
The current ideas involve a combination of getting more flexibility from both nuclear plants and wind farms, she said.
Butters of the power producers said a prepared speech to the Toronto Board of Trade on Tuesday that figuring out how to deal with the intermittent surpluses is “the single greatest impediment to ongoing confidence in the system.”
Campbell noted that many of Ontario’s nuclear units are due for mid-life refits starting in a few years.
That will require some to shut down for lengthy periods, which would ease potential surpluses.
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