Perpustakaan Digital ITB

In 2019, the government of West Nusa Tenggara province formulized Rencana Umum Energi Daerah Provinsi, a provincial energy planning which strategizes the practice of prioritizing renewable energy usage. Lombok Island as a highly favored tourism spot, particularly the West Lombok Regency, is to be planned for transition to renewable energy resource converted from the tidal current in Lombok Strait. The calculation on predicted energy demand shows a power deficit of 86.62 GWh at West Lombok Regency in the year of 2046. Hydrodynamic modelling and a simulated design of tidal stream farm are needed to analyze the potential of energy in the design location. Based on the performed hydrodynamic modelling, the potential location is located on the east of Penida Island at the range of -8.783, 115.656 to -8.783, 115.663, which is then determined as the design location of tidal stream generator farm. The depth in this location surpasses 200 m with a median current speed of 1.1 m/s. Based on references about tidal energy conversion, the conversion instrument needs to have the highest capability of optimizing the amount of power converted from the current speed. The chosen instrument is Seagen S/F manufactured by Marine Current Turbines with a rated power as high as 2 MW. The average turbine power production in the potential location is estimated to be 0.49 MW, which is still in the range of allowable extracted energy from the water channel, which has the upper bound of 1.75 MW. Hence, an optimal exploitation of the turbine power production is allowed. In order to satisfy the power demand of West Lombok Regency, a tidal stream farm is designed with 20 sets of tidal stream generators. A 25-year period financial analysis with 12% rate of return concludes the levelized cost of electricity at Rp 3,482.12/kWh. This value is above the range of average cost of electricity in Indonesia, prevailed by the cost needed for electricity transmission and conversion and followed by fabrication cost. It is estimated that an increase in the number of generators per farm will lower the levelized cost of electricity, but the decrease in the levelized cost of electricity will not be significant when a huge capital cost is invested for the project. This design concludes that there is a huge potential in Lombok Strait for tidal current energy owing to the location depth and current speed.