A year behind schedule and $18 million over budget, the latest high-voltage line of the BC Hydro grid has been completed from Merritt to Coquitlam.

The new line parallels the existing main line supplying the Lower Mainland and Vancouver Island from hydro dams on the Peace and Columbia Rivers. It was originally to be completed in 2014, but the main contractor fell behind and BC Hydro used its own crews to complete one of the most difficult portions, a 19 km stretch north of Hope.

The final cost for the 247 km line is expected to be $743 million, which Energy Minister Bill Bennett said is about two per cent more than the initial $725 million budget.

“There is an ongoing arbitration between BC Hydro and [contractor] Flatiron Graham as to who’s going to bear the cost of the delay, because the project was delayed by a year,” Bennett said in an interview Friday.

It’s the first 500-kilovolt line added to the BC Hydro grid in 40 years, to keep up with demand from a growing southwestern B.C. population and increase reliability in the event of disasters.

“You always have the potential for a big avalanche or a mudslide, even an earthquake, to take out one or two of your big transmission lines, bringing electricity in from the two rivers, the Columbia and the Peace,” Bennett said.

NDP energy critic Adrian Dix said the project started out with a $600 million estimate, making it $143 million over budget. He said it’s the latest in a series of cost overruns, including the Northwest Transmission Line north of Terrace, the Dawson Creek-Chetwynd line and the Iskut extension in the northwest.

Bennett said BC Hydro is under-budget on its overall capital construction plan, including $100 million under budget on reconstruction of five generating units at the W.A.C. Bennett Dam on the Peace River, and there is no additional effect on rates.

BC Hydro is committed to a capital budget of $2.4 billion a year for the next 10 years, including construction of the Site C dam on the Peace River and reconstruction of the Ruskin Dam in the Fraser Valley and the John Hart Dam on Vancouver Island.