Energy Economy of Households With Photovoltaic System and Battery Storage Under Time of Use Tariff With Demand Charge

Abstract

Power utilities are introducing cost-reflective tariffs, such as a time of use tariff to incentivise electricity use during off-peak periods, some of which include a demand charge during peak periods. The uptake of such tariffs depends on their economic benefits compared to other tariffs. The impact of such emerging tariffs on the household energy economy has not been widely investigated in the South Australian context. This research analyses the energy cost of grid-connected homes with photovoltaic (PV) systems under a time of use tariff with demand charge, recently introduced in South Australia. First, an optimization problem is formulated to minimize the annual household energy cost under a time of use tariff with demand charge, which is also applicable to other tariffs. Then, four types of South Australian PV-installed households are analysed with various battery energy management strategies and tariffs. The results show that a time of use tariff with demand charge can deliver savings in household annual energy cost, which can be further increased using the most appropriate energy management strategy for each tariff. Another key finding is that with battery storage, the time of use tariff with demand charge can reduce the peak load on the distribution feeder by 35% compared to the ordinary time of use tariffs.

Keywords

• Battery energy management strategies
• battery energy storage
• energy cost
• optimization
• renewable energy sources
• solar photovoltaic system