Towards a practical resource assessment of the extractable energy in the Agulhas ocean current

Abstract

In a found region of energetic flow in the Agulhas Current, two locations are analysed. It is found that the current core borders on the mid-shelf (91m depth) location and off-shore (255m depth) location lies within its predominant path, with mean velocities of 1.34m/s and 1.59m/s respectively at a 30m depth. In the period analysed only one large meander is noted at a depth of 30m. The percentage current reversals are 4.1% and 3.1% at the mid-self and off-shore locations, respectively.The most suited developed technology found to potentially deploy in this current is Minesto Deep Green turbine. The found capacity factor and specific yield for one Minesto (DG-12) 500kW turbine at 30m depth is estimated to be 62% with (4886kWh/year)/kW for the mid-shelf location and 76% with 5416(kWh/year)/kW for the off-shore location. Through a simplified analysis, the capacity credit of a possible 2000MW array is analysed. It is found that an ocean current power plant can add to the load carrying capacity of the country and outperforms onshore wind power plants in this respect. The largest barriers at present are the cost and mooring challenges which presents a need for a detailed economic assessment to determine if associated costs of working in deeper waters (off-shore site) are justified.