Optimization of Own Electricity Usage with Electricity Supply from Solar Cells at Darajat Geothermal Power Plant

At Darajat Geothermal Power Plant there is the use of the generator's own electricity for equipment such as cooling water pumps, lubricating oil pumps, oil transfer pumps, lighting lamps, heaters and others. The cost of own-use electricity used by the equipment based on the selling price of electricity from geothermal power plants to PLN is 1,119.74 Rp / kWh. With the potential of solar radiation of 4.90 kWh/m² per day, optimization of electricity consumption using solar cells and batteries will be carried out. The price of the solar cell is assumed to be 12,000,000 Rp/kW, the battery inverter is 2,000,000 Rp/kW and the battery is 2,350,590 Rp/kW. The lifespan of solar cell equipment and batteries is 20 years. This paper will be simulated in 4 cases and the result will be the price of electricity based on the value of capital divided by the total electricity produced by solar cells and batteries for 20 years. Case 1 when using solar cell day and night using batteries and the result of electricity price for case 1 is 718.648 Rp kWh. Case 2 when using solar cell day and night using its own electricity from the generator and the result of electricity for case 2 is 990.952 Rp/kWh. Case 3 when using solar cell and battery, at night using battery and the result of electricity for case 3 is 711.77 Rp/kWh. Case 4 when using solar cells and batteries, at night using electricity itself from the generator and the results of the case 4 electricity price is 978.005 Rp/kWh. Based on the 4 case simulations, the price of electricity will be cheaper if during the day using a solar cell plus battery and night using a battery, as in case 3, the price of own electricity power plant is 711.77 Rp/kWh.