Overview and Outlook Regarding the Shutdown of Nanao Ota Thermal Power Station Unit 2
Hokuriku Electric Power Company
Nanao Ota Thermal Power Station Unit 2 (rated output: 700 MW)
The transformer is believed to have suffered an insulation breakdown after a lightning strike entered the main transformer.
Company response
Operation of Nanao Ota Thermal Power Station Unit 2 was suspended
Around spring 2027
The Company will implement necessary measures, including strengthening its lightning arresters.
Approximately ¥20 billion (mainly due to higher costs for procuring alternative power supplies)
Fiscal 2026
The Company will carry out major repairs, including replacing components inside the main transformer, with the aim of restoring the unit around spring 2027. The Company expects to secure the necessary supply capacity during the shutdown through operation of other thermal and hydroelectric power plants and market purchases. It will implement necessary measures, including strengthening its lightning arresters.
The Company will promptly disclose any matters that require disclosure in the future.
| Item | Details |
|---|---|
| Event name | Overview and Outlook Regarding the Shutdown of Nanao Ota Thermal Power Station Unit 2 |
| Date of occurrence | 30 December 2025 (Tuesday) |
| Date recognized / date notice received | 30 December 2025 (Tuesday) (the date on which an abnormality in the main transformer was detected during operation) |
| Subject Entity | Hokuriku Electric Power Company |
| Target Locations / Products | Nanao Ota Thermal Power Station Unit 2 (rated output: 700 MW) |
| Cause | The transformer is believed to have suffered an insulation breakdown after a lightning strike entered the main transformer. |
| Amount of Impact on Business Performance | Approximately ¥20 billion (mainly due to higher costs for procuring alternative power supplies) |
| Accounting period in which recognized | Fiscal 2026 |
| Suspended operations | Operation of Nanao Ota Thermal Power Station Unit 2 was suspended |
| Scheduled resumption date | Around spring 2027 |
| Measures to prevent recurrence | The Company will implement necessary measures, including strengthening its lightning arresters. |
| Outlook | The Company will carry out major repairs, including replacing components inside the main transformer, with the aim of restoring the unit around spring 2027. The Company expects to secure the necessary supply capacity during the shutdown through operation of other thermal and hydroelectric power plants and market purchases. It will implement necessary measures, including strengthening its lightning arresters. |
| Planned follow-up disclosure | The Company will promptly disclose any matters that require disclosure in the future. |
Items this document does not state (12)
These are items the company does not state in this document. We do not leave them blank, nor fill them in from other sources or by inference.
The reasons the company gives
The company's own explanation, not something inferred from the numbers.The damage to the main transformer is believed to have resulted from a lightning strike entering the transformer and causing an insulation breakdown. The impact on results is due mainly to higher costs for procuring alternative power supplies during the shutdown.