Hydro Ottawa's new Time-of-Use rates

I received today the notice from Hydro Ottawa explaining their new Time-of-Use billing scheme.

Quick look at the new rates

My conclusion is that it seems to raise costs for the average use case, but it's possible to lower costs slightly compared to their current level by shifting usage to off-peak periods (though I think it's unrealistic to expect to be able to save money). The price for on-peak usage (6 hours per day on weekdays) rises a lot.

The old "anytime" rate, on my latest bill (April-June), was 6.8 cents/KWh.

The new rates are:
Off-peak: 5.9 c/KWh
Mid-peak: 8.9 c/KWh
On-peak: 10.7 c/KWh
Hydro Ottawa TOU Billing Analysis

Assuming a constant load (unrealistic), and weighting these rates by the number of hours a week they apply, you get a new composite weighted rate of 7.29 c/KWh, about 7% higher than the current "anytime" rates.

If you want to keep paying the same amount as today, you'd have to have a usage profile solving for (X: off-peak, Y: mid-peak, Z: on-peak):

5.9X + 8.9Y + 10.7Z = 6.8
(any point on that plane will yield the same cost as today's rate, but the practical application is unintuitive)

So with a weighted rate only 7% higher than today, I think it's not going to be terribly more expensive, as long as you make at least a token effort to move usage outside the On-Peak timespan.


The reporting is actually pretty cool:
Screen shot 2011-07-14 at 7.34.12 PM

It presents hourly, daily, and monthly stats, and allows downloading the data as a spreadsheet. This is actually an improvement I've been wishing for for a long time, in contrast to the previous data, which only gave you monthly usage. Now I wish I could get the same data for my gas consumption.


Keith MacDonald said...

Interesting analysis (and useful!). I wonder where did your screen cap of the reporting come from? (The one at the end of the post showing the hourly, daily and monthly stats?

jpdaigle said...

Keith, the screen cap is my actual usage reported on the website. You can register now at hydroottawa.com/myhydrolink.

We can see a 1-week dip where I was away traveling, so it's clearly working.

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