Methodology for analyzing electrical energy options for isolated areas

Abstract

There are isolated areas 1n many countries which cannot be connected by grid systems due to technical or economic reasons. In some of these isolated areas generation and supply of electricity do not exist or even if they exist, the history of load growth of these areas is not properly maintained. It needs to be recognized that the generation plan of an isolated area of the above nature should be different from the conventional planning process. The generation planning process starts with the forecast of load during the planning horizon. In the case of isolated areas the planner must consider the unconventional energy sources, especially the solar and the wind sources and hydro. Previous studies showed that these sources deserve the planner's consideration along with the conventional energy sources. The incorporation of sola~ and wind sources in the list of competing methods of generation essentially requires the appropriate models of these" sources suitable for a planning process. However, it has not been attempted so far to develop a technique of load forecasting suitable for an isolated area without electricity or without the history of load growth. No attempt has been made so far to develop appropriate models of a wind turbine generator,WTG and a photovoltaic generator,PVG. This research presents a load forecasting technique of an isolated area where the electric power supply as a source of energy has not been started yet or the history of load development 1.S not available where the supply 1.S 1.n operation already. The technique introduces the concept of deriving the load demand of an isolated area from the forecasted load of another area using a comparative factor. The technique starts with the identification of the variables on which the load growth of an isolated area depend. It also evaluates the contribution of each function towards the load growth. The research work also develops the probabilistic models of a WTG and a PVG. These models are based on the concept of" multistate representation of a generating unit. The basic data used for a WTG is the bivariate function of wind velocity and temperature while that for a PVG 1.Sthe bivariate function of insolation and temperature. These models are compared with the models developed t"rom the conventional concept of univariate function,that is,in the cases where the output of a WTG is taken as function of wind velocity only and that of a PVG as a function ,of insolation only. I The proposed load forecasting technique and the models of a WTG and a PVG. are applied to find out a most desirable plan of a realistic isolated area. In this planning process the conventional sources are also considered while due attention has been given to the reliability and the presently existing cost structure of the various components.