The Northwest Territories Power Corp. plans to bill the Department of National Defence and Joint Task Force North for repairs to a hydro transmission line brought down by a military helicopter.

The costs have been mounting since the accident a week ago that caused a power outage in Yellowknife. Since then, the city's electricity has come from diesel-fuelled generators.

NTPC is currently paying for the repairs, including daily helicopter flights to the site of the damaged lines. Expert crews from Grande Prairie, Alta., have also been flown in to help with the repairs.

Brendan Bell from the Northwest Territories Power Corporation says he has been assured the military will foot the bill for the repairs to the broken hydro line near Yellowknife. (CBC)

"We’ve been assured … that DND intends on compensating us so that ratepayers aren’t forced to pay for this accident," NTPC chair Brendan Bell said.

The corporation wants to get power from the Snare hydro system flowing to the North Slave region as soon as possible.

"The quicker we can get our hydro capacity repaired the better shape the system will be in. We’ve also been very fortunate that it’s not 40 below – it’s been good weather for repairs," Bell said.

NTPC estimates the transmission lines will be restored by the end of this week.

An NTPC worker reaches for the severed line during the repair process. Since the hydro transmission line was cut, electricity in the City of Yellowknife and nearby Behchoko has been provided by diesel-powered generators. (CBC)

The Department of National Defence is investigating how its helicopter flew into the transmission line, which is clearly marked on maps.

The military has not confirmed it will reimburse the power corporation for the full cost of the repairs. However, it has given NTPC the details the corporation needs to make a formal request to the Crown, which represents Canada’s military, in order to be reimbursed for the repairs.