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Confusion Over the Consumption Charts | Tuesday, January 17, 2012

Today's question: When I look at the horizontal bar graph that shows hydro energy available, consumed hydro energy and diesel energy we are using, it looks like we are not using all the available hydro energy, but are using diesel energy. Why is this?

Thanks for your question. We acknowledge this can be a confusing aspect of the chart.

The available hydro (shown in light blue) is what we have the capacity to generate at any given time (in other words, what hydro generation units are available to us that are either running or on stand-by ready to run should we need them). However there are a number of reasons why we can't always use our full capacity before turning on the diesels. For instance, this winter we are limited in terms of what we can generate from our Mayo plants because of potential flooding issues downstream. That shouldn't be the case next winter, but at this particular time we must be careful to keep water flows to a certain limit.

Another reason is that during peak times of the day when demand is rising quickly (breakfast or dinner time), we turn on diesels before we have reached our full hydro capacity to ensure there is no break in service to customers.

Finally, during a power outage you may see that we have hydro available but yet we are burning diesel. That's because we can usually restore power more quickly using diesel than hydro.

We hope this helps clear up the confusion.