How would a link between these two regions benefit Alaska?

There are quite a number of benefits a link between Alaska and British Columbia provides Southeast.  First, because British Columbia abides by Federal Energy Regulatory Commission rules, it's energy transmission entity BC Transmission Corporation charges the same wheeling (transmission) rate from Prince Rupert to Vancouver as it charges from Vancouver to the border near Blaine, Washington.  This means that if a Washington utility wanted to sell power to someone in Alaska the transmission rate would be a minor component of the cost.

What the above means to a utility in Alaska is that it could purchase power from a U.S. power producer or utility at a very low cost for use in Alaska.  An Alaska power producer might sell it's renewable power at a much higher cost to some lower forty-eight entity at the same time.  So Alaskans may benefit from the interconnection in seeing a reduction in their costs because lower forty-eight utilities wish to purchase renewable energy - even at a higher cost.