The cost of a controversial B.C. pipeline keeps rising, leading to plunging share prices

North American pipeline operator TC Energy Corp on Wednesday raised its cost estimate more than expected for completing its troubled Coastal GasLink project, sending share prices sharply lower.

First announced in 2018, the 670-km  pipeline will transport natural gas from northeastern British Columbia's Peace River region to the Shell PLC-led LNG Canada facility on the northwest coast of B.C., which is Canada's first liquified natural gas export terminal.

The long-delayed pipeline, owned by private equity firm KKR & Co Inc, Alberta Investment Management Corp and TC, has been dogged by problems including protests over environmental concerns, inflation and mountainous terrain that has forced TC to move pipe with ski lifts.

The company attributed the cost increase to a labour shortage, poor work by contractors and adverse weather.

Coastal's costs are now up 30 per cent to to C$14.5 billion, from the project's previous estimate of C$11.2 billion, which was already raised by 70 per cent in July from the initial budget. Analysts at BMO, Scotiabank and RBC said the latest increase was slightly higher than expected.

Costs could increase by another C$1.2 billion if construction extends well into 2024, TC added.

"Given the history of cost overruns ... we believe that the cost and timing of the project will be an overhang for the stock," said RBC analyst Robert Kwan, in a note.

TC's Toronto-listed shares fell 6.5 per cent and have lost 18 per cent since the company warned in November that Coastal's costs were increasing.

Chief Executive François Poirier said the increase was disappointing but the company remains focused on mechanical completion by the end of 2023. Work is 83 per cent complete.

Among Coastal GasLink's problems, the company says workers were attacked by masked assailants last February, damaging equipment and construction trailers worth millions of dollars. RCMP have released few details about the investigation.

The company has also been fined multiple times for environmental violations, costing more than $450,000.

It faces opposition from multiple groups, including supporters of a group of hereditary Wet'suwet'en chiefs whose territory the pipeline passes through.

Last month it was announced that LNG Canada, the facility that will process and export gas from the pipeline overseas, will be powered by natural gas rather than electricity, further increasing the project's carbon footprint.

The expansion of oil pipeline Trans Mountain, owned by the Canadian government, has also seen cost hikes and delays.