Semiconductor materials used for making photovoltaic (PV) cells have defects and impurities due to constraints of keeping production costs low. Electrically active defects that are distributed over the bulk material lead to reduced overall performance of a photovoltaic (PV) cell. In this study an adaptable Light Beam Induced Current (LBIC) system was designed in order to characterize the local performance of PV cells. The system uses a laser source and objective lens mounted vertically above the sample on the X-Y stage. Two current pre-amplifiers are used for converting the photo-generated current from the PV cell and the signal from the reflection detector cell into a voltage that can be measured by the data acquisition board. Two configurations for measuring the photo-current maps of either bare cells or encapsulated PV mini-modules can be used. To add flexibility it was envisaged that the system would be built in such a way that it allows easy integration of carrier lifetime mapping capabilities while keeping costs to a minimum. The carrier lifetime measurement technique integrated into the LBIC system is based on the optical Open-Circuit Voltage-Decay (OCVD) method. In a single-crystalline silicon PV cell that was tested, photo-current and opencircuit voltage LBIC scans revealed shunting behaviour due to scratch marks on the front surface. The marks are believed to have been caused by poor handling during manufacturing process. Reduced photo-current due to edge shunting was observed towards the edges of the PV cell. In another sample of single crystalline silicon cell an edge shunt resulted in a 30 percent drop in photo-current measured. LBIC measurements performed on multi-crystalline cells revealed nonuniformities such as enhanced photo-current on one side of grain boundaries. These asymmetric enhancements of local photo-current are attributed to the incline of the grain boundary into the bulk of the material. LBIC results obtained from mini modules showed a high degree of mismatching from cell to cell. It is well known that mismatching can degrade the performance of a PV module with series connected cells. The LBIC measurements presented also illustrated the negative effects of delamination on the photo-current of PV modules. The LBIC measurements performed on mini PV modules highlight some of the benefits of using an LBIC technique as a tool for investigating PV cell’s local photo-current response. The effective lifetime maps obtained highlight the importance of optical OCVD method as a tool that can be used in conjunction with conventional LBIC technique. Effective minority carrier lifetimes around 40 ms were measured on a single crystalline silicon cell of 2.5 x 2.5 cm2. Local features such as cracks and lifetime degrading defects were revealed by LBIC maps and were also confirmed on effective lifetime maps. The results presented demonstrate the importance of using effective carrier lifetime maps to complement photocurrent maps of PV cells and identification of areas where defects are located.

The main objective of this study was to investigate the performance of grid integrated PV systems. A data acquisition (DAQ) system was developed to monitor the performance of an existing grid integrated PV system with battery storage. This system is referred to as a grid assisted PV system. A data logger was used together with the inverters built in data logger to monitor environmental and electrical data on a grid tie PV system which was deployed during this study. To investigate the performance of these grid integrated PV systems PV and BOS device characterization was performed. This was achieved by using current voltage curve tracers and the DAQ system developed. Energy yield estimations were calculated referring to the literature review and a meteorological reference for comparison with measured energy yields from the grid tie PV system.

Research report submitted to the faculty of Commerce, Law and Management, University of Witwatersrand, in 50% fulfilment of the requirements for the degree of Master of Management in the field of Public and Development Management. March 2018 / The outputs in this report are based on the experiences, beliefs and perceptions of a crosssection of Solar Photovoltaic industry stakeholders on whether Local Content Requirements is an appropriate policy instrument for building a local industry and the extent to which the Local Content Requirements of the Renewable Energy Independent Power Producer Procurement Programme have led to an increase in the South African solar component manufacturing capacity since the programme’s inception in November 2011. Protectionist policies, including Local Content Requirements, were used by now industrialised countries to develop their respective countries, and continue to be used to this day despite World Trade Organisation prohibitions. Four models on building local industries are discussed and their relationship to the two research questions explored. Interview participants agreed that the Renewable Energy Independent Power Producer Procurement Programme was instrumental in building a large-scale local renewable energy industry in the country, created jobs and excitement around manufacturing capacity potential. However, many believe that programme design and implementation interventions are required to improve the programme’s localisation impacts. The latest draft Integrated Resource Plan’s sizeable allocation for Solar Photovoltaic until 2030 presents an opportunity to drastically improve localisation benefits for the country. / GR2019

MESMEG / Department of Mining and Environmental Geology / Solar energy development is experiencing significant growth due to national interest in increasing energy efficiency, reducing dependence on fossil fuels, increasing domestic energy production, and curbing greenhouse gas emissions. Northern Cape is generally known to be one of the preferred areas for the generation of solar energy in South Africa, and even in the world, due to its abundant solar radiation. Although this area has abundant potential for solar power generation, not all the areas are suitable for construction of solar plant facilities especially those that are prone to sand storm and dust accumulation. Consequently, site evaluation is very crucial for planning, design and construction of the solar facility. The main objective of this study was to determine the suitability of a proposed site at Kakamas in the Northern Cape for construction of a photovoltaic solar facility. The specific objectives of this research were to assess and establish all the geotechnical aspects that may have an impact on the development of the site, to explore the surface conditions at the proposed site and to establish the soil properties and comment on the use of the on-site soils in the construction of the solar facility. Other specific objectives included to determine the variability of ground conditions and effects of such variability on the proposed development and to provide foundation recommendations for the design and construction of the solar facility. In order to obtain this information, methods such as desktop studies, geological survey, soil survey, magnetic survey and soil profiling were employed to obtain information about the geotechnical aspects of the study area and properties of the on-site soil. Field tests such as cone penetration and resistivity survey and laboratory tests such as foundation indicator test, California Bearing Ratio, pH and permeability test were also performed in order to determine the engineering, behavioral and hydraulic properties of the soil. The results of the geologic and magnetic survey indicated that the study area is underlain by mainly igneous and metamorphic rocks such as gneiss, quartzite, pegmatite, gneiss and calcrete. The results of the soil profiling and the resistivity survey showed that the study area is comprised of sandy soil with either two or three horizons while the cone penetration results revealed high variable soil consistency and stiffness which ranged from very loose to very stiff soils. The particle size distribution, atterberg limits and grading modulus indicated that the study area is characterized mainly by dry, cohesionless and non-plastic to slightly plastic coarse-grained sandy soil with sand content ranging from 71- 96%. From the CBR results, it was found that the soils in the study area generally classifies as G6 material and can be used as base, sub base and backfilling material in accordance with the TRH 14 specifications. The permeability test results indicated moderately permeable sandy silt soils with coefficient of permeability ranging between 1x10-3 to 8x10-3 cm/sec and ground water was encountered at 1.3 m depth. The material excavatability indicated variable material on site ranging from soft calcretes with soft excavation to highly competent material such as quartz and dorbank which require hard excavation while the side wall stability of trial pits indicated stable pit walls during the investigation giving an indication of stability of long pit excavations. The foundation analysis showed that driven piles and earth screws are the ideal foundation types for this site and that the site is generally suitable for construction of the solar facility provided all the recommendations are implemented. / NRF