The Value of Diversity in Electricity Supply

Today has some compelling data that demonstrates the value of diversity in assuring secure electricity supply. Diversity in both generation sources and geography is important.
In Ontario we are highly dependent on nuclear power,, which supplies over 50% of demand. You could argue that we are over dependent on nuclear. Today, 6 out of 16 of our nuclear reactors are off line for maintenance. That’s 37% of the reactors. Fortunately, our demand is low due to mild weather, and today is Sunday, when many businesses are closed. We have to build back up supply for our aging reactors. After all, the oldest nuclear reactors are at the Pickering plant built in the late 1960’s.

In the late 1960’s, I was 10 years old. Our family had one car – a Ford. You don’t see those cars on the road anymore, because it is extremely difficult to keep equipment operating for over 50 years. Come to think of it, you don’t see many cars from the 1990’s on the road today either.

I had a farmer ask me once why the wind turbines my firm operated seemed to be off line for maintenance a lot. They may have been down for about 10 days/year (that kind of performance would have been a dream for a nuclear reactor). I asked him if he had ever tried to run his tractor 24 hours a day for a year without maintenance. He got the point – mechanical equipment needs maintenance.

So diversifying our supply makes sense. In Ontario, waterpower supplies 25% of supply, natural gas 11%, wind about 4%, with a smattering of biomass, and solar. The unreliable nature of our nuclear supply suggests we should increase these other sources, to ensure reliable supply.

With wind, diversified geography helps smooth output considerably. We have a heavy concentration of wind in Chatham Kent/Essex on western Lake Erie, with almost a third of the turbine capacity, at about 850 MW. Even more is located along the rest of Lake Erie. A fair bit is located on Lake Huron – 350 MW. There is some in Central Southwestern Ontario ~ 230 MW. There is over 200 MW near Kingston, and 200 MW near Sault Ste Marie, and 100 MW near Thunderbay.

At this time (noon), all three of these last wind farms are producing almost nothing, as there is little wind where they are located. But the province as a whole is producing 1450 MW from wind. The wind is concentrated on Lake Erie and Lake Huron at this time.

Of course weather systems move. And it will likely be windy in eastern Ontario tonight, and this wind will persist after it becomes calm elsewhere.

Fortunately, geographic diversity of wind farms is improving. The 30 MW EDP Renewables South Branch project, north of Cornwall has come on line. This is now the most easterly project in the province. The 60 MW McLean’s Mountain on Manitoulin Island is being commissioned now, and is producing power. This fills a geographic gap between the Lake Huron projects and the Sault. More geographic diversity not only improves the consistency of wind output, but it also reduces transmission losses, as the power doesn’t need to be sent as far.

Of course, the output of solar can be firmed with geographic diversity as well, as cloud density reduces output in some areas, while other can be sunny.

Improving the diversity of our electrical supply by source and geography just makes sense.

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