"It would give Alberta export capacity in times of surplus or import capacity should we run into shortages," Southern, who is also president of the Calgary-based Atco Group, told shareholders at the energy conglomerate's annual meeting.
Southern has no plan for when a proposal could be brought to regulators.
But she said the Alberta Electric System Operator, which oversees the province's wholesale electricity market, is looking for such an addition to the power grid to be in place by 2010 or 2011.
A 500 kilovolt line, to service existing needs in the booming province, would cost about $500 million — about the same amount as a transmission line currently proposed between Edmonton and Calgary, Southern said.
"If it were built with the long-term vision of adding more generation and import-export capacity, that project could triple in size," she added.
Although Atco could handle that on its own, Southern says the preferred option would be to partner with at least one other entity.
Atco is forecasting $650 million in new capital spending for 2006 and similar spending in 2007 and 2008.
"Alberta has to catch up with the infrastructure to accommodate the growth in the province," said Southern.
Last month, Atco Ltd. reported first-quarter earnings rose to $63 million from $42.6 million in the 2005 quarter. Quarterly revenues fell to $732.7 million from $814.6 million, mainly due to lower activity in Atco Structures' operations in Europe and reduced recovery of natural gas costs as Atco Gas stopped selling natural gas from its storage operations.
Net income for the three months ended March 31, which included an $11.7 million after-tax gain on the sale of land in downtown Calgary, amounted to $1.05 per share, up from 71 cents per share in the comparable 2005 period.
At the annual meeting, shareholders approved a plan to increase shares in the Calgary-based conglomerate to 20 million from eight million. That might suggest Atco is priming itself for a major acquisition, but Southern said that's not so.
"Not the kind of acquisition we had in 1980 where Atco acquired Canadian Utilities. That was a bit like a minnow swallowing a whale," said Southern. "But if we could find the right asset that fits with our existing business skills, we would like to avail ourselves of that opportunity."