Neighborhood storage systems are energy storage systems that decouple electricity consumption from electricity generation. Such storage batteries or battery storage systems are used as local grid storage systems for grid relief and for supplying quarters and entire districts. Neighborhood storage systems store surplus energy and feed the stored energy into the low- voltage grid.
Typical areas of application are therefore the storage of solar power from photovoltaic systems, power from wind energy or from combined heat and power plants. Due to the nature of energy generation and use, battery storage systems are used as home storage for day-night buffering and store the excess energy of the PV system for a few hours or a few days. Storage batteries used in residential areas have correspondingly higher nominal capacities and can store excess energy for days or weeks and release it as needed.
Quarter storage batteries are mostly lithium-ion batteries or lithium-polymer batteries, but lead-acid batteries are also used, which are connected to the photovoltaic system via AC or DC coupling. Furthermore, sodium-sulfur batteries and redox-flow batteries will also be used in the future. Energy Conservation and Distribution Systems( ECDS) with Battery Management Systems( BMS) ensure the correct power distribution between charging and consumption current. With time-of-day electricity pricing, storage battery charging could also come from the low-voltage grid. Since neighborhood storage systems use the public power grid for charging and discharging, grid fees, EEG surcharges and electricity tax are incurred.
Depending on the concept - whether for domestic use or for housing estates - district storage units are more or less voluminous and can be the size of a refrigerator or anISO container. Their battery capacities can be less than 10 kWh and include sizes into the higher MWh range. With the introduction of mobile charging stations for electric vehicles, the powerbanks used for them also lend themselves to energy buffering of excess electricity produced.