Until this thread started up, I wasn't up to date on how BC compares to other provinces and states on power imports and exports. Powerex (the BC Hydro trading company) is easily the biggest electricity trader in Canada - "British Columbia (B.C.) was responsible for 84% of Canada’s electricity imports. Although B.C. has generating capacity to meet internal demand, it tries to maximize the value of its generation by trading with the U.S. During the day, when U.S. electricity prices are higher, B.C. increases its hydroelectricity generation and exports electricity to the U.S. to earn more revenue. Overnight, when U.S. electricity prices are lower, B.C. significantly reduces its hydro generation, letting its hydro reservoirs refill while importing cheap electricity from the U.S." [
source]
Powerex currently uses four large export transmission lines "This system is interconnected with the western U.S. by two 500-kilovolt transmission lines on the West Coast between B.C. and Washington state; one 230-kilovolt line connecting B.C. and Washington on the east side; and a 500-kilovolt line to the east, connecting B.C. with Alberta." [
source]
In 2021 BC exported 11,430,000 MW.h of electricity, and imported 7,528,000. 61% of our exports went to California, 21% to Washington and 6% to Arizona. We exported to 14 states, and imported from 12. The vast majority of our imports came from Washington (86%) and California (11%). [
source].
While 10 years ago we imported power generated by coal (in Montana) and gas (in Washington), now we only import from clean sources (wind and hydro). [
source]. We're moving from 93% clean to 100% clean generation, as are California and Washington, our main electricity trading partners. We're currently at 96.5% renewable sources [
source]. Alberta has only around 18% renewable electricity, although wind and solar projects are coming onstream rapidly and coal is being phased out (but replaced by gas, which already provides about half Alberta's electricity generation).
This all seems to suggest to me that we have more than enough power for our own needs for some time, and that our imports and exports are all about keeping prices as low as possible. BC Hydro publications confirm that, in effect we are using our hydro facilities as batteries, to supply power when demand is higher, and wind or solar supplies are inadequate. As those sources are expanding fast both across the Rockies, and to the south, we might see even more imports and exports to maintain renewable supply at the cheapest cost. It would seem that Alberta ought to be using all the green power they can generate to substitute for their thermal production, but maybe the efficiency/cost argument (and when their green power is available) would justify adding another 500-kilovolt line.