In the past, BPA has curtailed wind turbines during the snowmelt season, when hydroelectric dams often produce power that far exceeds demand. The action has led to a legal standoff between wind project owners and the grid operator.
BPA said it believed oversupply costs could be between $10 million and $50 million. It also said the chances of curtailment were lower as the region's only nuclear plant - the Columbia Generating Station - was due to be refuelled during the period.
In 2012, BPA displaced 47,000 megawatt hours of generation with energy from the hydro system at a cost of $2.7 million.
In March last year, BPA submitted a proposal to the Federal Energy Regulatory Commission (Ferc), that BPA would cover revenue losses suffered by wind farm owners as a result of curtailments.
It also stated that wind curtailment would become an action of last resort, taking place only after all possible reductions have been made to the output of both hydroelectric and thermal power plants.
In 2011, BPA displaced approximately 97,500 megawatt hours of generation with hydro energy. BPA's policy at that time, called Environmental Redispatch, did not include a mechanism to reimburse generators.
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