The Alberta Electric System Operator and BC Hydro are to work together to restore transfer capacity on the British Columbia-Alberta intertie, which operates at levels well below its rated capacity.
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Alberta can import about 700 MW to 800 MW from British Columbia and Montana, according to Angela Anderson, a spokeswoman for the AESO. The grid operator expects to increase its overall import capability to 1,500 MW, with most of the work being finished in the 2018 to 2020 timeframe, she said.
The BC-Alberta intertie is rated at 1,200 MW for importing into Alberta and 1,000 MW for exports. However, for various reasons, including a new transmission link with Montana, it usually imports between 400 MW and 500 MW range, according to Anderson.
The 230-kV Montana-Alberta Transmission Line, or MATL, allows Alberta to import about 310 MW and export about 315 MW, Anderson said.
When the MATL line started operating in September, the AESO reduced the import capacity on the BC-Alberta intertie by up to 200 MW, a move that BC Hydro expected would lead to more frequent curtailments on the intertie.
Reduced capacity on the BC-Alberta intertie led BC Hydro to propose a "headroom tariff" in December that would have charged the AESO for its alleged use of BC Hydro transmission capacity.
BC Hydro argued that the Alberta grid operator effectively set aside BC Hydro transmission capacity to allow for flows of energy to Alberta to meet its operational needs.
At a January meeting, BC Hydro said the limits were forcing BC Hydro to curtail its transmission customers. The transmission limits have reduced the power trading income of Powerex, BC Hydro's trading arm, according to the utility.
The AESO opposed the proposed headroom tariff.
BC Hydro has shelved that proposal though because of the new agreement with the AESO.
Under the agreement, the AESO and BC Hydro will look for operational and infrastructure solutions to increase overall system reliability and commercial availability of the BC-Alberta intertie "over time," according to a notice they released Wednesday.
"Going forward, both parties will continue to work together to develop further details of potential solutions, including timelines and expected outcomes," the notice said.