The tunnel is being built to divert more water from Niagara Falls to the Adam Beck power station, which will be able to generate enough additional electricity to power 160,000 homes.
But Big Becky, the massive boring machine that's digging the 10-kilometre, 14-metre wide tunnel has run into some dangerous rock conditions and is behind schedule. OPG disclosed late last year that the project will be late and over budget, but the details are still under review.
Global News, citing an interview with John Murphy, OPG's executive vice-president of hydro, reported that the project could cost $1.6 billion and be three years late under a worst-case scenario. It also reported the original cost estimate as $600 million.
However, OPG spokesperson Ted Gruetzner told the Star that the original estimate was $985 million. He doesn't dispute the $1.6 billion figure, just the suggestion it's more than doubling the cost of the project. In reality it would represent a 62 per cent increase.
Gruetzner also said it's unclear how much of that additional costs, if any, will be borne by electricity ratepayers. OPG is still negotiating its contract with Strabag AG, the Austrian company leading the project. A dispute review board is expected to determine who will bear the cost or whether it should be shared between the two parties.
"Once we do get the final timelines we'll announce that," said Gruetzner, adding that the update could come next month.
OPG says that even in a worst-case scenario the project is still economical because the tunnel will deliver clean electricity for more than 90 years. But critics say the company should have known about the rock conditions before committing to such a complex engineering project.