Comparative Evaluation of Alternative Tariffs on Energy Cost of Households with PV and Battery

An effective way to mitigate global warming is to replace fossil fuels by renewable energy sources such as PV systems. South Australia (SA) has stepped ahead by having one of the highest residential PV penetrations in the world. However, because of the significant difference between the current feed-in-tariff and the retail price of electricity, households are paying a high annual electricity bill. One way to reduce the bill is by installing battery storage. This paper proposes a method to find the optimal battery size for a given PV system to minimize the annual electricity cost of a high energy consumption household of SA. Factors affecting optimal battery size, for example, type of electricity tariffs and energy management strategy are used in formulating the optimization problem. Simulation results show that the time of use tariff is more economical than flat tariff for PV owners under a range of feed-in-tariffs. In addition, it is shown that energy management strategy which uses battery energy during peak period to meet household load demand is less beneficial than basic strategy where discharging time is not restricted.