Effect on energy supply contribution by incorporating rooftop photovoltaic systems within the City of Johannesburg

The City of Johannesburg (COJ), an economic hub of South Africa with a 17% national growth domestic product (GDP) and contributing 47% of Gauteng provincial economy, has been greatly impacted by the energy sustainability challenges that beset South Africa especially since the 2008 energy crisis. In Queensland, Australia, rooftop solar photovoltaic (PV) has demonstrated to be an impeccable renewable (RE) source that has been utilised at a large scale to ease energy sustainability problems. The availability of over 2200kWh/m² of annual average solar irradiance, vast amounts of unused rooftop spaces and land scarcity within COJ makes rooftop photovoltaic (PV) deployment a viable solution to ease the city's energy concerns. The research thus analyses the impact of implementing rooftop PV systems within COJ from an energy security improvement, greenhouse gas (GHG) emission reduction and employment creation viewpoints using a case study of Langlaagte, Roodepoort and Sandton testing stations. Results indicated that 2.28GWh/year could be generated at 15.4% PV panel efficiency and 79% performance ratio contributing approximately 12.14% of the three sites' energy requirements, with a potential to produce 84.76GWh over a 25-year PV module lifespan. The results highlighted annual carbon emission reductions of 2349.43 tonnes, contributing over 12% of the annual emission reductions for the three sites, lessening emissions by 58735.75 tonnes over a 25-year lifespan. The generated energy capacity resulted in the creation of 68 temporary and permanent jobs in the city. Large scale deployment of rooftop PV systems can greatly reduce COJ's current 28.2% unemployment rate. The research results can assist COJ to evaluate the sustainability implications of a full-scale deployment of PV systems on the city's suitable rooftops. The research equips the city with informative data that can aid in strategy and policy formulation as the city endeavours to achieve its short and long term sustainability objectives.