Load Factor Improvement on Daily Load Curve Using Pump Storage to SavingProduction Cost

Several factors that affect the cost of producing electrical energy in electrical power systems such as changes in the price of fuel for electricity generation (power plant generator), and changes in the load curve. The price of generator fuel varies depending on the type. The power plant with coal fuel is cheap and can be used to serve basic and medium loads all day. While the power plant with gas or oil fuel is very expensive and usually used to serve peak loads with a duration of 5 hours. The higher the peak load on the daily load curve, the greater the cost of producing electrical energy in the power system. Peak load generally occurs at night where almost everyone uses electrical equipment or during working hours. In Indonesia, especially on the Java and Bali islands, the peak load occurs from 17:00 to 22:00. This study uses the Java Bali 500 kV electrical power system. The load factor is a comparison between the average load for certain time intervals with the highest peak load at the same time interval. For example, 1 day, 1 week or 1 month. While the average load for a certain interval is the amount of electricity production (kWh) in that interval divided by the number of hours from that interval. The greater the load factor or close to 1, the cost of producing electricity will be cheaper or can be interpreted to be more economical. Making load factor approaching 1 will be used pump storage in the electric power system. The storage pump will act as a generator at peak load, thereby reducing the height of the peak load on the load curve. While at the baseload, pump storage will act as a motor load which serves to pump water from the lower reservoir to the upper reservoir, so that the baseload height will increase. Using this pump storage role will make the daily load curve flatter. The results of this study, in scenario 1 with load factor 0.89507, the cost of producing electricity for 24 hours is $ 20,251,047.78. While in scenario 2 with a load factor of 0.9672, the cost of producing electricity for 24 hours is $ 19,618,067.33. Of the two production costs obtained savings or difference is $ 632,980.45.