The prices are set by the Alberta market through the operation of its power pool. The model is the same in both cases. The result of the value of energy is different depending on the level of demand. We tend to be a buyer when the demand in Alberta is low, they're in surplus, and the prices are lower, and we tend to be a seller when demand is high in Alberta and the value is higher.
On October 16th, 2017. See this statement in context.