May 21, 2022

Hydro Ottawa Limited Major Event: May 21, 2022

Prior To Major Event

1. Did the distributor have any prior warning that the Major Event would occur?

No. Winds were forecasted however the severity of the winds exceeded what was expected.

Environment Canada issued an alert for a Severe Thunderstorm Watch at 2:12 pm on May 21, 2022. Hydro Ottawa started experiencing outages between 3:45 - 4:00 pm thereafter.

Derechos are challenging to predict. On days when derechos form, it is often uncertain whether any storms will form at all. But if they do, the chance exists for explosive development of intense winds.1 Derechos are among the most destructive weather events that Canada can experience. While the wind intensity cannot equal a strong to violent tornado, the expanse of area affected in orders of magnitude is greater, often resulting in greater overall impact than tornado event.2

2.    Did the distributor train its staff on the response plans for a Major Event?

Yes. Hydro Ottawa has processes and procedures in place that staff are trained on. In addition, Hydro Ottawa conducts practice drills on an annual basis. 

During the Major Event

1. Please identify the main contributing Cause of the Major Event as per the table in section of the Electricity Reporting and Record Keeping Requirements. Please provide a brief description of the event (i.e. what happened?).

Other. The primary cause of interruption for the Major Event was due to a Derecho, a widespread, long-lived wind storm that is associated with a band of rapidly moving showers or thunderstorms.

This event was considered to be a Major Event day based on the IEEE Standard 1366 method. The daily SAIDI value of 2308.27 on May 21, 2022 exceeded the daily threshold of 5.05, as determined by IEEE Standard 1366. The total number of customer hours interrupted on May 21, 2022 was 35,491.

There were areas damaged from the storm that experienced outages on the days after the storm, which are also part of the Major Event. The total outage hours for the full storm period was 13,367,385.

2. Was the IEEE Standard 1366 used to identify the scope of the Major Event? If not, why not?

Yes, the IEEE Standard 1366 was used.

3. When did the Major Event begin (date and time)?

May 21, 2022 at 3:36 p.m.

4. Did the distributor issue any information about this Major Event, such as estimated times of restoration, to the public during the Major Event? If yes, please provide a brief description of the information. If no, please explain.

Yes, please see further details below regarding how Hydro Ottawa provided restoration estimates information. 

Due to the number of individual and complex overlapping outages throughout the service territory our outage map was unable to reflect the real time situation after the storm. This included not fully reflecting the extent of the 24/7 progress made by our team, nor estimated times of restoration (ETRs) due to the unprecedented damage, construction and cleanup required. As a result, the outage map was temporarily removed from our website in an effort to prevent frustration and confusion, or create false hope as the situation remained fluid. From the very first day, to ensure customers were still informed of the impact of the storm and to prepare for extended outages based in their area and the restoration priority process Hydro Ottawa issued public statements through multiple mediums that the storm recovery would be a multi-day restoration effort.

On Monday, May 30th with the bulk of the electricity grid fully operational, Hydro Ottawa relaunched its online outage map, tailored for customers who still remained without power. These new ETRs were defined by the day on which power would be restored to specific areas instead of times. We were also able to provide ward-specific information to respective city councilors at the same time.

5. How many customers were interrupted during the Major Event? What percentage of the distributor’s total customer base did the interrupted customers represent?

180,946 customers were interrupted on the day of the major event plus an additional 11,528 customers were impacted on the days after the storm due to damage from the storm. This represented 54% of Hydro Ottawa's total customer base.

6. How many hours did it take to restore 90% of the customers who were interrupted?

The major damage from the wind started May 21st at 3:36 p.m. and 90% were restored by May 28th at 6:00 p.m.

7. Were there any outages associated with Loss of Supply during the Major Event? If so, please report on the duration and frequency of Loss of Supply outages.

Yes, there were three outages due to Loss of Supply during the Major Event and all were restored within eight hours. However, the distribution system was also severely damaged in those regions; therefore restoration was delayed until the distribution work was completed.  

8. In responding to the Major Event, did the distributor utilize assistance through a third party mutual assistance agreement with other utilities? If yes, please provide the name of the utilities who provided the assistance?

Yes. Four high voltage lines contractors, four neighbouring utilities, three forestry contractors, three civil contractors and one communications contractor for a total of 450 workers were utilized for assistance with storm recovery.

9. Did the distributor run out of any needed equipment or materials during the Major Event? If so, please describe the shortages.

No. Given the current global supply chain issues, inventory was managed very carefully during the storm event.  No actual inventory shortages were encountered as a result of aid received from numerous utilities, contractors and suppliers, which was facilitated through Electricity Canada (formerly the Canadian Electricity Association) and EDA channels.

After the Major Event

1. What steps, if any, are being taken to be prepared for or mitigate such Major Events in the future (i.e., staff training, process improvements, system upgrades)?

Others. A company wide debrief is being conducted due to the magnitude of the event that took place May 21, 2022. Findings will be actioned and Hydro Ottawa has and will continue to look at lessons learned as a result of the major event. 

A derecho is defined as a widespread, long-lived, straight-line wind storm that is associated with a fast-moving group of severe thunderstorms known as a mesoscale convective system.  


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