<p>While the share of electricity produced by hydro is projected to remain consistent in places like the USA and the EU, many countries are planning major changes to their generation fleets. For example, in Switzerland, it is expected that the planned phase-out of nuclear power will coincide with wide-scale integration of rooftop PV by 2050. Such changes in the energy mix induced by transitions toward renewables will have a wide range of impacts on the associated electricity markets and networks. Additionally, the unique operational flexibility of hydro units can be essential to enable greater integration levels of renewable resources. To help plan such energy transitions, it is critical to understand the operation and benefits of hydropower and hydro cascades, especially for countries like Switzerland where hydro already plays a leading role. Unfortunately, most studies involving the use of hydropower in an electric power system tend to consider the point of view of the system operator even though under many liberalized markets, the operation of hydro units is set by the owner to maximize their profits. Such studies also often neglect uncertainties related to hydropower operation and instead assume perfect knowledge of the system conditions over the simulation horizon. This paper presents a methodology to overcome the aforementioned limitations and enable the realistic representation of hydropower units that is necessary for planning energy transitions. We optimize the operational choices of a hydropower cascade owner with multiple linked hydro assets and the ability to participate in several energy and reserve markets while also accounting for the impact of market price uncertainties on the owner's operating decisions. The versatile optimization model created includes a detailed representation of any selected hydro cascade's topology, constraints to reflect the machinery characteristics, and a rolling horizon approach to account for the price uncertainties in the daily operating schedule. The model is first validated using historical data for a hydro cascade in Switzerland and a perfect-knowledge approach. Next, price uncertainty is added to improve the historical simulation results and find a trade-off between accuracy and computational time. While results assuming perfect knowledge were satisfactory, including price uncertainty adds significant value by making resulting production profiles more in line with the historical profiles. Using such a methodology allows more realistic simulations of power systems to investigate the impacts of electricity system&nbsp;transitions and better plan effective policies to achieve a desired transition.</p>

Modeling and Validation of Hydro Cascade Operation Considering Price Uncertainty

Paper Proceedings: https://asmedigitalcollection.asme.org/POWER/POWER2021/volume/85109

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