Application of green energy for EV battery charging station

The Well-to-Wheel (WtW) CO2 emission of the electric vehicle (EV) strictly depends on amount of a carbon dioxide (including transmission and conversion losses) required to produce an electric energy used to charge EV batteries. Value of the WtW emission may be lowered by increasing a share of low-pollutant power plants i.e. using renewable energy or nuclear power, however it needs a large financial investments and it is very long process, taking over a dozen years. Even in the case of countries having a large share of low-emission power plants (Germany), a smart grids must be applied in order to optimize a value of WtW CO2 emission. Usually batteries are charged during night, where energy demands are relatively low and at the same time wind turbines supplies majority of electric energy to the grid. Presented idea of the battery charging station described in this article has a local character. It uses photovoltaic panels as a source of "green" electric energy. As a consequence the value of WtW emission for an EV batteries charged in this station equals to 0 g/km. The charging station uses EV battery swap thus the time of staying in the station is shorter in comparison with normal or even fast charging. The battery swapping technology uses replacing of the discharged units mounted in EV by fully charged ones. The batteries are placed in special try, which enables a quick mechanical and electrical connecting and disconnecting. Moreover, batteries stored in the station may be used as an energy storage devices and makes charging process optimization easier; moreover, they can be used as an element of a smart grid system. The article describes model of charging station using both photovoltaic and quick EV battery swap.