A smart algorithm to optimally manage the charging strategy of the Home to Vehicle (H2V) and Vehicle to Home (V2H) technologies in an off-grid home powered by renewable sources

Abstract

The reduction of electrical energy needs in buildings is accompanied by the use of hybrid renewable energy systems (HRES) for the production of energy on-site to be used for appliances and lighting and also for mobility through electric vehicle (EV) charging. With reference to this framework, the paper compared the tradition Home to Vehicle (H2V) technology with the Vehicle to Home (V2H) technology in HRES for residential users. The HRES consists of a photovoltaic (PV) generator, a wind generator, an electrical storage system and a charging station for an EV, in a stand-alone context. V2H technology provides for the use of the EV as an emergency energy source if the generation and storage systems are unable to guarantee the satisfaction of the residential load. Considering an off-grid single-family user located in the Sila National Park (Calabria, Italy), two enhanced EV charging strategies were investigated that both foresee the possibility of EV charging at night and an additional extra charge during the day to reduce the load demand and the produced HRES excess energy, which must be dissipated in an off-grid context. The two charging strategies differ in the choice of whether or not to carry out nocturnal charging depending on the EV state of charge. For this purpose, an algorithm is proposed that can optimally manage both enhanced EV charging strategies for both H2V and V2H technologies. The dynamic simulations of the HRES operation were carried out through TRNSYS, for the dynamic simulation of the PV and wind systems, which is coupled with MATLAB to dynamically simulate the residential battery and the H2V and V2H technologies. Starting from the hourly results obtained, weekly and yearly energy analyses were carried out for two different residential storage system sizes to identify in which conditions V2H and charging strategies provide beneficial effects in terms of energy missing to satisfy the load and overall energy required by the load.