The energy sector in South Africa is highly driven by coal, making the country one of the highest greenhouse gas (GHG) emitters in the world. As one of the signatories to the UN Framework Convention on Climate Change, the country is determined to reduce its carbon footprint. In this paper, the role of green hydrogen produced from renewable energy sources to the South African energy sector is presented with the objective of increasing the share of renewable energy in the country's energy mix. First, an overview of the South African energy sector is presented with the aim of pointing out the energy inputs and the usage patterns. Thereafter, the potential of renewable energy resources that could support green hydrogen production is highlighted. Some of the key findings show that 67% of total primary energy sources in South Africa is coal. Industrial and residential sectors account for the bulk of energy usage with 53% and 19%, respectively. It is also revealed that industrial and transportation sectors account for 51% and 38%, respectively, of GHG emission with the residential sector contributing only 2%. The renewable energy resources in South Africa are encouraging for green hydrogen production. Solar has an average 2500 h of sunshine per year with daily total solar irradiation between 4 and 6.5 kWh/m² day. The annual average wind speed ranges from 5.6 to 8.7 m/s with power density between 218 and 693 W/m² at 10 m anemometer height in the coastal region of the country. The biomass potential is estimated as 83.91 Teragram per annum with hydropotential of 4.851 GW. This paper is important as it will serve as a firsthand scientific information for optimal development and investment in green hydrogen production in South Africa.

In this study, wind characteristics and wind power potential of Johannesburg are investigated using 5-min average time series wind speed collected between 2005 and 2009 at anemometer height of 10 m. The statistical distribution that best fits the empirical wind speed data at the site of study is first determined based on the coefficient of determination and root mean square error criteria. The statistical parameters and wind power density based on this model are estimated for different months of the year using standard deviation method. Economic analyses of some wind turbines are also carried out. Some of the key results show that the site is only suitable for small wind turbines in a standalone application. A 10 kW wind turbine with cut-in wind speed of 3.5 m/s, rated wind speed of 9 m/s, and cut-out wind speed of 25 m/s seems most appropriate in Johannesburg with the lowest cost that varies from 0.25 to 0.33 $/kWh.

In this paper, the complementary characteristic of battery and flywheel in a PV/battery/flywheel hybrid energy storage system is explored for a solar PV-powered application. The impact of hybridising flywheel storage technologies with battery on the ageing of battery and its economic effectiveness when used with a PV system is presented. The ageing of a lead acid battery is modelled using Schiffer weighted Ah-throughput model while the economic analysis is modelled using total cost of ownership approach. Two scenarios (i.e. PV/Battery and PV/Battery/flywheel) are created to appreciate the complementary characteristics of a hybrid storage system in a PV-powered application. Sensitivity analysis was also carried out to understand the effect of a change in degradation and corrosion limit as well as charging and discharging current on the ageing of a lead acid battery. Some of the key results reveal that a hybrid of Battery/Flywheel presents a lower capital and total cost of ownership compared to battery only when used in a PV powered-combined fishery and poultry farm. The results also show that the life of a lead acid battery can be extended when combined with a flywheel compared to a battery only storage system.