Customer case stories 12.10.2026
Storm Hannes demonstrated the value of smart meters in power grid outage management
In December 2025, storm Hannes swept across Finland, leaving up to 76,000 Elenia customers without electricity and causing more than 2,800 fault repair assignments. During the storm, Elenia made extensive use of real-time data from smart meters as part of its outage management operations. The data helped ensure customer electrical safety and locate faults, supporting the restoration of electricity supply as quickly as possible.
When power outages affect tens of thousands of customers simultaneously, every minute counts. During storm Hannes, around 300 installers, forestry workers and machinery contractors from Elenia’s partner companies joined Elenia’s own personnel in the repair efforts. Alongside the field work, a crucial role was played by the real-time overview of grid conditions and the extent of the outages maintained by Elenia’s control centre.
Storm Hannes was the first major widespread outage event in which Elenia was able to make full use of its metering system, renewed over the past few years. More than 400,000 new-generation Aidon smart meters continuously provide information on grid conditions, including power outages, voltages and neutral faults. This gives the control centre a more accurate view of the grid, even under exceptional conditions.
Automatic neutral fault disconnection improved electrical safety
According to Teemu Suvela, Control Centre Manager at Elenia, the most significant benefit of the new-generation smart meters during storm Hannes was their ability to automatically disconnect the electricity supply in the event of a neutral fault.
When a meter detects a neutral fault, it automatically disconnects the property from the electricity network, even before an installer arrives. During the storm, approximately 600 meters performed automatic neutral fault disconnections, improving customer electrical safety and reducing the risk of damage to electrical equipment.
Neutral faults always require urgent attention, but automatic disconnection makes the affected site safe even before repair work begins. This enabled the control centre to prioritise repairs according to the overall situation without compromising customer safety. At the same time, repair crews could be directed quickly to medium-voltage network faults where repairs would restore electricity to the largest possible number of customers.
Voltage data from smart meters helped pinpoint fault locations
Smart meters continuously transmit information on distribution network conditions and voltages to the control centre. During storm Hannes, this information was used to help locate faults in some cases.
By comparing measurement data from different distribution transformer areas, Elenia was able to identify sections of the network where voltage asymmetry occurred. This made it possible to narrow down the locations of broken medium-voltage conductors to specific line sections between two substations. Repair crews could then be directed straight to the fault locations, avoiding time-consuming network inspections and fault searches.
Metering point status information supported customer communications
Despite the scale of the storm, Elenia restored electricity to more than 60,000 customers within the first 24 hours. Repair work continued for several days in the worst-affected areas, but storm Hannes also provided valuable experience of how a digitalised power grid can support a distribution system operator’s operations under exceptional conditions.
Keeping customers informed about estimated outage durations and the progress of repairs was particularly important. During storm Hannes and the subsequent days of repair work, Elenia sent nearly 400,000 text messages and almost 80,000 emails to its customers. Information from smart meters indicating whether electricity supply was available at individual metering points also supported customer communications.
Storm Hannes demonstrated that security of electricity supply depends on several factors: a weather-resilient network, skilled professionals and effective cooperation in the field. Equally important is real-time information that helps establish an accurate picture of the situation when the power grid is under extreme pressure. New-generation smart meters provide precise, up-to-date information to support decision-making in the control centre.
