Economic Comparison of Conventional and Optimum Scheduling of the Electric Transmission/Distribution Substations in Jeddah City Using the Net Present Value

摘要

This paper focuses on the electricity field in Jeddah city. It is devoted to predicting and economically scheduling the needed number of electric transmission/distribution substations for long-term time horizon (10 years). Forecasting is based on predicting the electricity total demand in each year and then finding the needed number of substations for each year. The forecasting is used to predict the projected annual total consumptions for years from 2009 to 2018 using an artificial Neural Network (ANN) depending on the historical data for six predictor variables for the time period 1979-2008. Scheduling is based on a dynamic programming model under the constraints of needed demand and budget availability. The objective function is to minimize the total cost; the decision variables are the number of transmission/distribution substations to be built in each year (stage). The state of the system is the number of transmission/distribution substations still required in remaining years. The optimum schedule for constructing and operating the substations is found and compared with the conventional method of scheduling used by the company. The comparison is based on the net present value for both alternatives. The net present value (NPV) = 1446.783 and 1748.981 millions Saudi Riyals (SR) for the optimal and the conventional schedules, respectively. So the NPV for the optimal schedule saves SR 302.198 millions, i.e. about 17% over the planning horizon of the next 10 years.