Healthcare institutions consume large amounts of energy, ranking the second highest energy-intensive buildings in the commercial sector. Within developed countries, the energy consumption of healthcare institutions may account for up to 18% of the overall energy usage in commercial sectors. Within developing countries, such as South Africa, the energy consumption of healthcare institutions is observed to be a close second to the food service sector. Energy consumption of healthcare institutions per bed typically range from 43–92 kWh per day. In this paper, the largest energy consumers in South African healthcare institutions are identified and appropriate energy-efficiency (EE) initiatives are proposed, in terms of performance, operation, equipment and technology efficiency (POET). Two main thermal energy consumers are identified as heating, ventilation and air conditioning (HVAC) and water-heating systems. These systems are critical to patient health and may be classified as non-deferrable loads. Therefore, several initiatives are suggested to improve the energy efficiency and demand-side management capability of these systems. These initiatives are subdivided into different levels: the conceptual level, active level, technical and further improvement level, as defined in the POET framework. At each level, energy-efficiency initiatives are introduced based on potential energy savings and the effort required to achieve these savings. In addition, model predictive control (MPC) approaches are discussed and reviewed as part of the further improvement section. Average possible energy savings ranged from 50%–70% at the conceptual level, while energy savings of 15%–30% may be expected for energy-efficiency initiatives at the active level. EE activities at the technical level and the further improvement level may result in savings of 50%–70% and 5%–10%, respectively.

A model is developed to optimise power sharing between two grid‐connected prosumers that incorporates photovoltaic and wind energy conversion systems operating in a peer‐to‐peer (P2P) energy‐sharing arrangement. The city of Durban, South Africa, where wind and solar resources are abundant, is selected as a case study to analyse power flows between selected prosumers. The model optimally manages power flows among micro renewables‐based energy generators while minimising the total cost of energy purchased from the power utility under a time‐variable pricing structure. To evaluate the economic feasibility of the suggested peer‐to‐peer energy‐sharing arrangement, a lifecycle cost analysis is conducted to determine when the proposed system will break even, in terms of money spent less achievable salvage value, using the suggested prosumers instead of providing power exclusively from the grid to satisfy load demands. The analysis predicts that the breakeven point will occur after 4.3 years at $13,500, with a projected saving at the end of the 20‐year lifecycle of approximately $60,536.82, or 47.42%. Furthermore, the ‘true’ payback period method is used to assess the economic behaviour of the proposed system with P2P energy‐sharing capabilities and indicates that the total investment cost would be recovered in 8.76 years. These results show that the optimally controlled peer‐to‐peer energy‐sharing scheme is economically feasible in the South African context and may be applied in any global location with similar operating conditions.

Stand-alone renewable energy systems implemented in residential areas reduce the magnitude of the crisis by means of lowering the electrical demand and associated costs of generation and distribution. Further steps can be taken to optimize the operation of these systems in order to improve their energy consumption. The development and application of optimization algorithms to existing and/or new setups can potentially improve electrical power consumption for hybrid arrangements while making the best use of renewable energy. This will not only reduce the energy cost to the consumer, but also reduce the greenhouse gasses produced by electricity suppliers. Therefore, this paper focuses on developing a mathematical model to minimize the electrical energy cost of the hybrid solar collector/electric water heating system through optimal switching control of an electric resistive water heater with the aim of increasing the efficiency of the overall energy consumption of the system whilst maintaining thermal comfort level of the user.