Simulation studies on WTG-FC-battery hybrid energy system

A stand-alone power system is an autonomous system that supplies electricity to the user load without being connected to the electric grid. This kind of decentralized system is frequently located in remote and inaccessible areas. It is essential for about one third of the world population which is living in developed or isolated regions and has no access to an electricity utility grid. The most people live in remote and rural areas, with low population density, lacking even the basic infrastructure. The utility grid extension to these locations is not a cost effective option and sometimes technically not feasible. This paper deals with the modeling and simulation of a stand-alone hybrid power system, referred to as "Wind Turbine Generator (WTG)-Fuel Cell (FC)-Battery hybrid energy system". It couples a Wind turbine generator (WTG), an alkaline water electrolysis, a storage gas tank, a proton exchange membrane fuel cell (PEMFC), battery and power conditioning units (PCU) to give different system topologies. The system is intended to be an environmentally friendly solution since it tries maximizing the use of a renewable energy source. Electricity is produced by a WTG generator to meet the requirements of a user load. Whenever there is enough wind speed, the user load can be powered totally by the WTG electricity. During periods of low wind speed, auxiliary electricity is required An alkaline high pressure water electrolyses is powered by the excess energy from the Wind generator to produce hydrogen and oxygen at a pressure. Gases are stored without compression for short-(hourly or daily) and long-(seasonal) term. A proton exchange membrane (PEM) fuel cell and battery used to keep the system's reliability at the same level as for the conventional system while decreasing the environmental impact of the whole system. The PEM fuel cell consumes gases which are produced by an electrolyser to meet the user load demand when the WTG is deficient, so that it works as an auxiliary generator. Power conditioning units are appropriate for the conversion and dispatch the energy between the components of the system. Batteries are used in this system back up purpose.