The utility released a report Tuesday saying its crews encountered a number of problems including higher than forecast winds in areas with an abundance of roadside trees as they scrambled to bring back power for homes and businesses.
The report is part of a review of Nova Scotia Power's response to the July 5 storm being conducted by the province's Utility and Review Board.
Nova Scotia Power faced criticism from the public as well as Premier Stephen McNeil and the Opposition Progressive Conservatives in how it handled its response to the storm.
In the 172-page report, the company acknowledges the considerable impact to customers who waited days for their power to be restored after the storm hit.
At one point, 245,000 customers in Nova Scotia were without power as a result of Arthur's damage.
"Post-tropical storm Arthur struck Nova Scotia with far more severity than weather forecasting had predicted," Nova Scotia Power's report says.
Wind gusts were up to 74 per cent higher than forecast in the Annapolis Valley, where the worst tree damage occurred, and the highest wind gusts were recorded at Canadian Forces Base Greenwood at 139 kilometres per hour.
Still, crews were able to restore power for 95 per cent of affected customers within five days of the storm, and all electricity was back eight days later — timelines consistent with other utilities in North America, Nova Scotia Power says.
In those eight days, Nova Scotia Power's call answering system fielded 425,123 calls, above the 416,664 calls it received in the two weeks following hurricane Juan.
The company says while its damage prediction model for emergency restoration didn't fail, the forecast used for planning purposes significantly underestimated the storm's impact.
In the storm's aftermath, many customers complained about a lack of communication and inaccurate predictions about power restoration times.
The company says its restoration strategy targets outages of 100 or more customers, but the storm saw more than 3,400 outages affecting fewer than 100 customers each.
"Customers who were among smaller pockets of outages grew frustrated because the ETR (estimated time to restore) strategy wasn't providing information accurate to their situation," the report says.
The utility also says its communications systems were swamped due to more calls from customers than ever before and capacity was reduced after technical problems occurred with its telecommunications supplier. More than 24,000 calls were disconnected by the system.
In the Annapolis Valley, which experienced the greatest damage from falling trees, Nova Scotia Power says its past trimming efforts were light because of narrower rights of way and a lack of support from property owners and municipal governments who want to preserve ornamental trees.
"The public has a competing desire for the preservation of ornamental roadside trees and electrical service reliability and there is no clear consensus on the appropriate balance," says the report.
The company suggests steps to improve its overall response include having more people in the field to get an earlier idea of the extent of storm damage in order to improve the accuracy of power restoration estimates.
The public and other interested interveners have until Sept. 9 to file their comments in response to Nova Scotia Power's report. The company has until Sept. 16 to file another response.
The Utility and Review Board will then determine whether any additional investigations are required, including a public hearing.
Arthur also blasted New Brunswick, leaving 140,000 customers in that province without power at its peak.