Abstract
Hydropower reservoirs in Norway are primarily operated to participate in electricity markets. For cascaded systems, producers rely on decision-support tools based on stochastic optimization to determine generation schedules under uncertain inflows and electricity prices. At the same time, regulated reservoirs contribute to downstream flood mitigation, a function expected to become increasingly important under climate change. However, flood mitigation objectives are rarely explicitly represented in operational scheduling models. This paper investigates how flood control objectives can be incorporated into stochastic hydropower scheduling using economic penalties on bypass discharge. A six-module representation of the Sira-Kvina hydropower cascade is used as a case study. Results show that in hydraulically constrained conditions, bypass penalties have limited impact on total bypass volumes but slightly affect the temporal distribution of bypass events. An additional experiment with doubled downstream reservoir capacity shows a somewhat clearer response to penalties, although extreme flows remain largely unchanged.