Generation expansion planning in a hydro-dominated system

Sri Lankan power system is predominantly hydro based, with an installed capacity of 1175 MW out of which 995 MW is hydro. Ninety eight per cent of the 1989 demand was met by hydro energy. The expansion analysis shows that by year 2010, hydro will contribute some 40% of the total demand. In order to evaluate the available energy of the existing and the candidate hydro projects, it is necessary to use an external model for integrated reservoir operations simulation. This paper briefly describes the model used to simulate the operation of the hydro-thermal system. The effect of seasonality and hydrology variation, the methodology adopted in creating WASP hydro condition data from the time series of hydro generation obtained from the simulation model and its implications are also discussed. Further, the need to modify the algorithm used in WASP-III to schedule the maintenance of thermal plants on available energy rather than on installed capacity for a hydro dominated system, and the necessity to produce more summarized information on the optimal expansion plan on the PC version of WASP-III are emphasized. (author). 3 refs, 7 figs