Impact of extensive residential solar water heating on power system losses

South Africa is in the grips of an electricity crisis. Currently, the bulk of power is produced at coal fired power stations which are located far from the large load centres. Solar energy is widely available in South Africa, and could be used to complement this coal based generation, and supply energy at the point of use. This paper aims to investigate the impact of residential solar water heating on power system transmission losses. Initially simulations were carried out in order to determine the impact of solar water heating on a household's electricity demand. These were done for households located in Cape Town, Johannesburg and Durban. A number of solar water heating installations in Cape Town were also monitored, in order to validate the simulation results. Lastly, a power system model was developed in order to investigate the possible impact of large-scale implementation of solar water heating, at varied penetration levels, on a transmission system. Using the model and the results obtained from the simulations, a utility impact analysis was carried out in order to determine the effect on transmission losses. It was concluded that large-scale implementation of solar water heating can be used as a means to alleviate loading and losses on power systems' transmission lines particularly during peak demand.