Alberta Saskatchewan Intertie Storage (ASISt)

The Alberta Saskatchewan Intertie Storage (ASISt) facility will combine existing Compressed Air Energy Storage (CAES) technology with an interconnection between the Saskatchewan and Alberta power grids. This will be the first CAES facility in Canada, and the first facility in the world to combine a CAES facility with an interconnection between grids. Located near Lloydminster on the Saskatchewan-Alberta border, the ASISt project will have an initial capacity of 160 MW generating capacity with the possibility of future expansion.

ASISt diagram

In short, CAES works as follows:

  1. When electricity is cheap (in Alberta, often coincident with wind supply since wind producers are price takers in the power pool) the facility will compress air into an underground cavern where it will be stored for future use.
  2. When electricity is expensive, the facility will release the stored compressed air into a series of generators and turbines in order to produce electricity.

This will help mitigate the price swings that occur in the Alberta electricity pool. For example, in the week of January 11, 2015 the price rose above $600/MWh on two occasions.

February 11 2015 Pool prices AESO

Purple bars indicate pool price
Source: AESO 2015

Due to the unpredictability of renewable electricity generation, these price swings would become more egregious if more wind or solar power is added to the grid. The ASISt project will allay these concerns and help to reduce the carbon intensity of the Alberta electricity market.

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