Grid catches flak for Helsinki power cuts

Finland's energy regulator has demanded a 'full and transparent' account from public utility Helsingin Energia of a grid failure that caused a blackout in Helsinki on 22 and 23 August.

The main grid operator and electricity distributor in the metropolitan area, Helsingin Energia, has been asked to clarify why the grid failure occurred and what measures the company intends to put in place to prevent a repeat.

Helsingin Energia is scheduled to present a formal account of the blackout by the end of September. The regulator said it could use the report as a basis for toughening up the rules.

The regulator said it was concerned that Helsingin Energia's automatic back-up systems took longer than expected to kick-in.

The public utility's preliminary findings suggested the failure was due to a malfunction which caused a short-circuit at the Kruununhaka power plant in Helsinki. The plant had just been restarted after a routine outage.

As a result of the short-circuit, all power plants in Helsinki and two out of the three main grid transformers which supply electricity to the Helsinki metropolitan area were switched off. The power plants affected included generating stations at Hanasaari, Vuosaari and Salmisaari.

The most serious blackout took place on the Saturday. On the previous day, disruption to power supplies was reported in the Helsinki suburbs of Espoo and Vantaa.

Helsingin Energia said the power cuts on 22 August were unrelated to the general blackout that took place at 20.30 the next day. The blackout lasted for two hours in central Helsinki and for up to three hours in eastern, southern and western districts of greater Helsinki until grid problems were resolved and full power was restored.

The outage halted the city's train, tram and Metro service. Passengers had to be evacuated from stalled underground trains in Hakaniemi. The blackout also closed retail businesses and brought manufacturing at factories to a halt.