Tidal energy resources assessment in Indonesia: A case study in Alas Strait

With the instability of oil prices and the increasing of people’s awareness in environmental problems, renewable energy is the key solution of these problems. Tidal energy, with its advantages of being predictable and its high energy density, is one of the most promising renewable energy forms. Indonesia’s topographic conditions with plenty of narrow strait between the islands and its strategic location between two oceans make the tidal energy development in Indonesia looks promising.This study is intended to assess tidal energy resources in Indonesia. A case study in Alas Strait, a pioneer study for this site, is selected among many prospective sites considering its relative shallow depth, high current velocity, and location which far from major shipping line. Princeton Ocean Model (POM) is used to model the flow pattern in the site. It uses the bathymetric map to represent the depth and applies tidal elevation in open boundary condition as generating force. The result from POM is then used to quantify the extractable energy resources using farm method.The model result shows that current velocity in Alas Strait is relatively high, i.e. could reach up to 2 m/s in certain locations during spring tide. Array of typical Marine Current Turbine (MCT) is then placed in specific locations in Alas Strait (depends on water depth) to simulate the tidal energy extraction. New method of estimating downstream current velocity based on direction of the flow is applied to calculate the total power from the array. This results in 27.065 GWh/month for current MCT scenario with depth limitation and 52.736 GWh/month for floating MCT scenario.To conclude, Alas Strait has the potential to be the location of MCT installation. This may be not feasible in the current time since the cost for implementing MCT is still relatively high. However, with the maturity of the technology, lower cost, and the urge to “go green”, this will be applicable in the future.