1. Techno-economic Analysis of an Off-grid Micro- Hydrokinetic River System for Remote Rural Electrification Central University of Technology Energy Postgraduate Conference 2013

2. Presentation outline Introduction Hydropower situation in South Africa Hydrokinetic System modeling and simulation Results and discussion Conclusion

3. Introduction Currently over 90% of South Africa's electricity comes from coal power. Government target: 10 000 GWh renewable energy contribution (biomass, wind, solar and small-scale hydropower ), Approximately 6000 to 8000 potential sites for traditional micro hydropower. The Use of Hydrokinetic power for river applications in South Africa. Objective of this study To investigate the possibility of using and developing hydrokinetic power for electricity supplies for rural and remote loads in South Africa. Simulation (HOMER): Compare the use of Hydrokinetic with other supply options.

4. Hydropower situation in South Africa SizeType Installed capacity (MW) Estimated potential (MW) Macro hydropower (Larger than 10MW) (i) Imported1 45036 400 (ii) Pumped storage for peak supply 1 58010 400 (iii) Diversion fed-5 200 (iv) Dam storage regulated head 6621 520 (v) Run of river-270 Small hydropower (from few kW to 10 MW) As above (iv) and (v)29.4113 Water transfer0.638 Refurbishment of existing plants8.016 Gravity water carrier0.380 Sub-total for all types3 730.353 837 Excluding imported from abroad2 280.317 437 Excluding pump storages using coal based energy700.37 237 Total “green” hydro energy potential available within the border of South Africa7 237 No significant development of hydropower in the country has been noted for 30 years

5. Hydrokinetic Technology Operation principle similar to wind turbine, Potential energy available almost 1000 time more energy from the hydrokinetic than wind. Advantages compared to the traditional hydropower: No dam, No destruction of nearby land, No change in the river flow regime, Reduction of flora and fauna destruction. Theoretically, a greater number of potential sites for hydrokinetic power can be identified.

6. System modeling and simulation HOMER: Hybrid Optimisation Model for Electric Renewable Problem: Unfortunately, HOMER is not equipped with a hydrokinetic power module considered in this study. Proposed solution: -The wind turbine components has been used with hydrokinetic input rather than wind-related information. -The wind turbine power- curve has been replaced with the hydrokinetic. -The wind speed information with the river current velocity.

7. Load estimation (rural household) The daily energy consumption (9.5kWh) The peak load at 3.4 kW Month Velocity (m/s) Clearness index Daily radiation (kWh/m 2 /d) January 5.31 0.6277.404 February 7.25 0.6467.178 March 6.09 0.6396.274 April 1.81 0.6385.200 May 2.67 0.6984.663 June 2.18 0.7584.522 July 1.84 0.7434.663 August 1.54 0.6414.804 September 1.41 0.6906.302 October 1.69 0.6076.443 November 2.83 0.5616.500 December 5.27 0.5536.613 Average 3.32 0.6385.873 Resources Water velocity in the worst month: 1.41 m/s, Viable depth: 1,8m, Width: 5,2m, Cross sectional area: 9.36m 2 P a = 1,075 kW

8. ComponentsInvestment costs Replacement costs O&M costsLifetimeDiesel price Lubricant HKP$9170/kW $20/yr25yr-- PV$4100/kW$3500/kW$105/yr20yr-- Battery (6V, 360Ah) $175$150$3/yr10yr-- Inverter$800/kW $10/yr15yr-- Diesel Generator 3.4 kW $2830 $0.5/h10yr$1.25/L$1.30/L Costs

9. Simulation results and discussion The architectures and costs of different supply options found feasible by Homer are presented below: SystemsHKPPVDG Size (kW)164.5 Number of Battery 7120 Inverter (kW)3.5 0 Rectifier (kW)3.5 0 CostsHKPPVDG Capital ($)11 4757 8802 830 Replacement ($) 4 6979 34420,300 O&M ($)8312 33755 991 Fuel ($)0075 971 Salvage ($)-290-967-264 Total NPC ($) 16 713 18 495154 829 COE ($/kWh) 0.387 0.4163.475 Grid extension distance (km) 0.9111.0713.1 Simulation results summary

10. Conclusion This paper aimed to investigate the possibility of using hydrokinetic power suitable to supply electricity to rural and isolated loads in South Africa where reasonable water resource is available. Simulations of the hydrokinetic power have been performed with HOMER software. The results have been compared with those of a diesel generator and PV while they are supplying the same load. The hydrokinetic system (composed of 1kW turbine, 3.5kW converter, and 7 batteries) has an initial capital cost of $11 475, a Net Present Cost of $16 713, and energy production cost of 0.387 $/kWh. The results of this study have led to the following further study recommendations: Identify sites and assess potential energy available, Develop policies supporting the development of hydrokinetic power in South Africa.