WINNIPEG -- The price tag for a controversial hydro line in Manitoba has soared again.

Manitoba Hydro says its new estimate for the BiPole Three project is $4.6 billion, up from $3.3 billion in 2011 and an original figure of $2.2 billion in 2007.

The Crown corporation says converter technology is the main reason for the price jump -- businesses that submitted bids are not planning to use new types of converters that are normally used for shorter routes.

Hydro CEO Scott Thompson says the extra cost will be paid over many years and will only mean an extra $4 a year for the average residential customer.

Hydro originally wanted to build a shorter, less expensive line down the east side of Lake Winnipeg.

But the NDP government ordered it to run the line far to the west to protect the boreal forest on the east side.