Abstrack:
Global warming ischallanging problem that need to be solved. One of the main challange in the global warming issueis reducing the carbon emitted to the atmosphere trough substituting fossil fuel by the green energy source. The geographical position of Indonesia which is located in the equatorial regions gives great potential for utilization of solar energy. This research was conducted to combine a conventional electricity source provided by the PLN with a photovoltaics(PV) systemas a Hybrid PV system. In this system the PV system acts as main power, whilethe electricity from the PLN as a backup power in office of the Pertamina Oil Fuel Terminal (TBBM) Rewulu, Yogyakarta. A Hybrid Solar Power System unit was designed to powermaximum 60 pieces of lamps with 9 watt power each. The designed system should be able to work 8 hours/day. The installed hybrid solar power system consists of 12 piece PV panel(@135watt peak), 80A MPPT solar charge controller, 2kW sine power inverter, 8 units 12V100Ah batteries, and a hybrid controller. It was designed with 80% efficiency due to loss of thePV system component. The measurement of the system have been conducted on the July 14th-20th 2014. The result showed that the minimum energy produced in acloudy situation PV at 15th July was 4.1 kWh,whereas on a sunny day at 17th July was up to 8.6 kWh, and energy rate on one week was 6.38kWh. The energy consumption for the lamps was 5.3 kWh per day, so in the sunny day the hybrid system is be able to fulfillthe energy demand. However, in the cloudy day the PV system is be able to supply merely a part of energy needed. Total annual electric energy that can be produced by the system was 2.061kWh/year. It givesannualy1.494 metric tons CO2reduction.