Operating rules for Temascal-Cerro de Oro hydropower system in Mexico

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Maritza Arganis, Rosalva Mendoza, Dominguez Ramon, Eliseo Elizondo, Irving Acencio Gasca

Wednesday 1 july 2015

11:30 - 11:45h at Central America (level 0)

Themes: (T) Water resources and hydro informatics (WRHI), (ST) Surface and subsurface flow interactions

Parallel session: 9K. Water resources - Water - food - energy nexus

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Stochastic dynamic programming based on the Bellman’s optimality principle was applied to get operating rules for the Temascal–Cerro de Oro hydropower dams, allocated in Papaloapan river basin in Veracruz and Oaxaca states in Southeastern Mexico. The two reservoirs are connected by the “Pescaditos” dike so that was also considering in the process of getting the operating rules. The objective function conciliates two opposite purposes in one hand to maximize the expected value of the generation benefits and in the other hand to minimize the spills and deficit condition. Penalty coefficients were considered in case of spill and deficit and additionally in the objective function penalty coefficients were considered in case of be above or below of two guide (the suggested levels in order to avoid possible damages downstream imposed by the Comisión Nacional del Agua and to accomplish a minimum electricity generation desirable for the Comisión Nacional de Electricidad). The useful storage capacity was divided in 22 states and eight stages were considered for the year by clustering months according to the average monthly inflows, the transition probabilities from one state to another were obtained with the relative frequency of the monthly inflows to the reservoir, minimum and maximum extractions were set for each stage. Hydrological years from October of year i to September of year i+1 were considered; monthly data of net evaporation and additionally the correlation between the inflows to the dams from one month or fortnight to another was also taken into account during the simulation. An annual historical record of 65 years were considered in the fortnight simulation. The operating rules can be expressed as well in monthly graphics as in an operating matrix, that can be easily used by the operators and also for the decision makers from the Comisión Nacional de Electricidad in Mexico.