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Modern hydroelectric power systems are largely characterized by variability and uncertainty in water resource obligations. The growing number of operational obligations for flood control, navigation, environmental obligations and ancillary services (including load balancing requirements for renewable resources) further the need to quantify sources uncertainty. The variations caused by these - factors require the hydropower system to have enough up and downward flexibility for control technologies such as dynamic optimal control load-following, unit commitment, automatic generation, to be effective. Therefore, it is increasingly important to adopting operational flexibility to better manage uncertainty and balancing reserves. The objective of this paper is to present and discuss approaches for assessment of the level of the available operational flexibility as a function of dynamic states and control input and how the available operational flexibility can be used by the hydropower producer in a comprehensive optimization reformulation to accommodate business procedures (e.g. operating at high forebay elevations or near zero productive outflow gradients) to drive the system in an efficient, safe and interpretable way. We consider simple metrics such as power capability and its derivatives as indicators for upward flexibility and effective energy storage capability for downward flexibility. Test results based on the Federal Columbia River Power System managed by the Bonneville Power Administration are presented and demonstrate how operational flexibility can be assessed and which role it plays in real-time operation.


Session S7-01, Special Session: Optimizing Short Term Reservoir Operations I



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