Power utilities across the northeastern states of the USA are continuing to assess and repair the damage to the region’s electricity infrastructure caused by hurricane Sandy.

Approximately 8.5 million electricity consumers across 21 states from North Carolina to Maine and as far west as Illinois were left without power after the so-called ‘superstorm’ made landfall in New Jersey on 29 October.

The hurricane-force winds, heavy rainfall and storm surges caused damage to overhead power lines and electricity substations throughout the region. Three nuclear reactors in the path of the storm experienced shutdowns while a fourth – Oyster Creek in New Jersey – was placed on alert due to high water levels in its water intake structure.

Some 2.6 million customers in the state of New Jersey lost power at the height of the storm while a further 2.1 million in New York state were affected.

Consolidated Edison, which supplies electricity and gas to more than 3 million customers in New York City, said that the Sandy had cause the worst storm-related damage ever in the company’s history. It has secured assistance from 1400 external contractors and mutual aid workers from other utilities to help with restoration efforts.

The US Nuclear Regulatory Commission (NRC) placed inspectors at eight nuclear power plants in the path of Sandy and also monitored the storm from its emergency response centres. It reported that safety systems at the three nuclear plants to trip during the storm – Indian Point 3 in NY, Salem Unit 1 in Hancocks Bridge, NJ, and Nine Mile Point 1, in Scriba, NY – responded as designed.

In Connecticut, United Illuminating Company (UI) said that 148 000 of its 700 000 customers were affected, while Connecticut Light & Power reported that over half a million customers lost power during the storm.

“The damage caused by the storm was as bad as we anticipated,” said James P. Torgerson, UIL’s chief executive officer. “We are proceeding full force to restore power to our customers as quickly and safely as possible.”