At the same time as the province heads to court over a law that would let Alberta turn off the taps, B.C.'s premier is wondering whether more gas could come through the pipeline at the root of the dispute.

John Horgan wants to see if the existing Trans Mountain pipeline could transport more gas to the West Coast, hoping the move would help drive down the price at the pumps.

He added light oil could also be sent and refined at the Parkland refinery in Burnaby.

He's hoping the proposal could be the start of a conversation about how Alberta, Ottawa and B.C. could co-operate.

"My message to them is, 'I'm worried about (prices) too,'" he said at a news conference Wednesday announcing a lawsuit against Alberta.

Shipping refined products that could be used in B.C. would make Horgan more likely to support the expansion, he said.

Earlier in the day, Alberta Premier Jason Kenney used gas prices as a reason why B.C. should already be behind the project.

"The B.C. government is doing everything it can to block the expansion of the very pipeline that would get Alberta oil and gas to the gasoline constrained Lower Mainland and beyond," Kenney said.

"This hurts ordinary families in British Columbia. This hurts Alberta."

But Horgan told media that the materials put before the National Energy Board on the TMX project didn't contemplate increasing refined product in any way.

Horgan didn't provide many details, but said prioritizing refined product in the pipeline would be a good thing in terms of gas prices, which recently topped 170 cents per litre in Vancouver.

So far, he said, there has been no commitment.

Leaders in Alberta have said they're more interested in exported diluted bitumen, because that's where the market is.

However, at least one expert says if Alberta did turn off the taps, as it is able to do after passing Bill 12 Wednesday morning, B.C. might not be the only province feeling the effects.

An affidavit states British Columbians use between 70,000 and 85,000 barrels of gasoline, and between 55,000 and 70,000 barrels of diesel each day.

The document obtained by CTV News was written by Michael Rensing, director of the low carbon fuels branch in the Electricity and Alternative Energy Division of B.C.'s Ministry of Energy, Mines and Petroleum Resources.

Whether directly or indirectly, Rensing says in the affidavit, Alberta supplies over 80 per cent of the gas and diesel used in B.C.

"It is clearly a major customer for Alberta refineries. If exports to British Columbia were disrupted, Albertan refineries would have an over supply and no easy access to alternative markets," the document says.

"Once storage capacity was exhausted, production would have to be curtailed, with corresponding losses of income, jobs and tax revenues."

The newly elected Kenney said he plans to "seek the path of diplomacy" before following through on his threat to restrict oil experts to B.C. Still, he warned Albertans would not tolerate any "obstructions" in getting the long-delayed pipeline expansion built.

A Calgary court will hear B.C.'s lawsuit – which claims the law allowing Alberta to limit energy exports is "unconstitutional" – on Tuesday. It's an emergency measure, as the province hopes to eventually strike down the law.

With a report from CTV News Vancouver's Bhinder Sajan