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2009
Conference Paper
Titel
Electric mobility and photovoltaics - the low voltage grid on the way to energy autonomy?
Abstract
Today's discussion about electric mobility contains a vision of dual use of battery storages in electric vehicles or in plug-in hybrid vehicles. On the one hand renewable energies provide a possibility for zero emission transportation; on the other hand the storages give the possibility to store fluctuating energy from the renewable power sources. Within this paper decentralized PV systems feeding into the low voltage grid and pure electric vehicles are considered. The approach contains two steps. First a system model of a low voltage grid with a huge fraction of electric vehicles and a 200 kWp PV generator is set up. With this system model a simulation study is carried out considering four different operating control scenarios. Whereas the first three scenarios are based on moderate assumptions, the fourth scenario describes an extreme case targeting a maximum degree of energy autonomy in the low voltage grid. The second step contains the ""Solar Mobility"" concept developed at INES, which seeks a synergy between electric vehicles, electricity grid, and PV generators. First demonstration of this concept with two electric cars and a solar car park is presented. In order to maximize the solar share of the vehicle charging needs for further developments are identified. The results of the simulation study and the results of the demonstration site show a need for optimized energy management systems, which determine the state of charge of the vehicles. Furthermore, vehicle chargers are needed which are able to cope with the fluctuations of the PV generation and which are able to adapt the charging power to the available PV power. Besides these topics one of the key questions today is the ageing of battery storages in the described scenarios. Therefore stress factors for the batteries have to be considered.