ST. JOHN'S, N.L. -- An arm's length study says that using large-scale wind power for Newfoundland and Labrador's future energy needs would cost much more than Muskrat Falls.

The study by Manitoba Hydro International says wind and thermal energy generation would cost about $3.5 billion more over 50 years than the proposed Labrador hydroelectric development.

The Progressive Conservative government has repeatedly said the project is the best option for the province.

The government is to decide in coming weeks whether to sanction Muskrat Falls at an estimated capital cost of $7.4 billion.

Critics say Muskrat Falls is too prone to cost overruns and that the province should consider incremental developments for its power needs.

Predicted capital costs have gone up by $1.2 billion since Muskrat Falls was first proposed in 2010 at an estimated cost of $6.2 billion.

The government says the price tag has risen in part due to advanced engineering and design improvements.

Muskrat Falls supporters say alternatives have been studied but they are too expensive.