A team of researchers from the University of South Australia has recently developed a new model that optimises how vehicle-to-home (V2H) systems interact with residential solar + energy storage systems. According to their report, home charging costs can be reduced by up to 16 with the V2H system7%。
The research team devised a unique optimization strategy that combines V2H technology with residential solar + energy storage systems to significantly reduce household energy bills. V2H is an energy transfer mode in which a family can use the battery of their electric vehicle to power the appliances in their home.
"Our study provides a new energy cost optimization strategy for households with electric vehicles, renewable energy generation units, and battery energy storage systems," the researchers said. Taking into account the multi-site charging needs and daily driving patterns of electric vehicles, we have designed a solution that can rationally arrange EV charging and V2H activities. ”
A key component in this model is the home energy management system (HEMS), which determines the input and output of household energy based on the price of electricity. HEMS can draw power from the grid, battery energy storage systems, or electric vehicles and can deliver power to these**. In addition, it can harness electricity from residential solar systems and electric vehicles.
The study assumes that HEMS operates in a time-of-use (TOU) environment, with electricity prices varying based on demand. The researchers compared the time-of-use tariffs of two Australian utilities, AGL and IO Energy. Although IO Energy's peak electricity price is higher than that of AGL, it offers a lower electricity price during off-peak hours.
The researchers explained that when residential solar power generation exceeds household consumption and EV charging needs, the excess electricity will be used to charge the battery energy storage system. Once the battery energy storage system is fully charged, the excess power is fed back to the grid. And when solar power generation is insufficient to meet household consumption and EV charging needs, HEMS will operate in one of three modes, depending on the three phases of time-of-use tariffs.
The team noted that the first mode is suitable for the last hour of off-peak periods, when electricity is imported from the grid. The second mode applies to the rest of the off-peak period, as well as the time when the electricity price is between off-peak and off-peak periods. In this case, the battery energy storage system will supply power to the home before electricity is fed from the grid. The last mode is that in the last hour near the peak electricity price period, the battery energy storage system can be charged with both the power from the solar power facility and the grid. For the rest of the day, the energy storage system will charge from the sun's excess electricity and provide power to the household load.
In addition, unlike battery energy storage systems, the charging and discharging of electric vehicles is limited by a variety of factors, including the user's travel time and parking location. The study also considered two types of electric vehicles, work and leisure. Work electric vehicles are mainly used for commuting to and from work and are parked at the work site during work. Recreational electric vehicles, on the other hand, are used for daily activities outside of work, such as shopping and education, and can be flexibly parked in public parking lots during the day.
The results of the study showed that using V2H technology is more economical than charging at home, reducing costs by 167% of energy costs. When considering outdoor charging options, the use of V2H technology to transfer energy can significantly reduce the electricity bill of household users. This discovery provides new ideas and solutions for home energy management.