02/19/2014 01:26 EST | Updated 04/21/2014 05:59 EDT

Inquiry into blackouts will assess reliability before and after Muskrat Falls

ST. JOHN'S, N.L. - An inquiry into power failures last month across Newfoundland will assess system reliability before and after the anticipated flow of Muskrat Falls hydro in 2017.

The Board of Commissioners of Public Utilities says an interim report by mid-May will review how the system failed and recommend changes needed for coming winters.

The board will then assess the system up to and after power flows from the $7.7-billion Muskrat Falls hydro project in Labrador.

Critics have questioned whether Crown corporation Nalcor Energy has a sufficient backup plan in case Muskrat Falls power fails.

But Newfoundland and Labrador Hydro, a Nalcor company, told the board in a pre-hearing that its inquiry should be short-term.

Its view was at odds with the province's other major utility, Newfoundland Power, which called for a longer focus to guide planning.

A key question is whether the province should shut down its main oil-fired Holyrood (HO'-lee-rood) power plant once Muskrat Falls is online.

Rotating and unplanned blackouts last month affected up to 190,000 customers on the island.

They were blamed on a cold snap, high winds and equipment that failed or was down for maintenance.