What is an estimated time of restoration?
An estimated time of restoration (ETR) is the time a utility expects supply to be back on for customers affected by an outage. It is also called an estimated restoration time (ERT). ETRs are used by electricity, gas and water networks and by telecommunications providers.
For planned outages, the restoration time is part of the notice given in advance. For unplanned outages, the ETR is set after the outage starts and usually changes several times as the network learns more.
How an ETR is set
ETRs are typically managed in the network’s outage management system and refined in stages:
- Initial estimate. When an outage is detected, the system or the control room sets a default based on typical restoration times for that kind of fault, area and time of day.
- Assessed estimate. Once a crew reaches the site and sees the damage, they update the estimate based on the actual repair needed.
- Revised estimates. Access problems, parts, weather, safety issues or competing priorities can push the time out. Partial restoration through switching may bring some customers back earlier than others.
- Restoration. Supply is restored and the outage is closed, although individual customers may still have a separate fault.
In a major storm, networks sometimes hold back specific ETRs until damage has been assessed and give a general message instead, because early estimates in widespread events are often unreliable.
Why the ETR drives contact centre demand
In an outage, the ETR is the single most requested piece of information. That has two consequences.
First, it is highly suited to automation. An AI voice assistant, IVR announcement, outage map or proactive outage notification can answer it instantly, freeing agents for hazard calls and customers who need more help.
Second, every change to the ETR can create a new wave of calls. When an estimated time passes without power returning, customers ring again. A missed ETR is one of the main causes of the secondary spikes seen during a call avalanche, and of complaints after the event.
Good practice in communicating ETRs
- One source of truth. Agents, IVR, AI, website, app and SMS should all show the same ETR, drawn from the same system.
- Update before it expires. Revise the estimate before the time passes, not after customers start calling.
- Say it’s an estimate. Plain wording such as “we expect power back by around 6pm, and we’ll update you if that changes” sets honest expectations.
- Give the next update time when no estimate is available yet.
- Explain the reason where you can. “The crew is replacing a damaged pole” is more reassuring than an unexplained new time.
- Think about who relies on it. Medically dependent consumers and businesses with refrigeration make real decisions based on the ETR, so long or uncertain outages may justify proactive contact.