Battery storage systems have long been common practice in off-grid photovoltaic installations (otherwise known as stand-alone solutions) in order to ensure that power is continuously supplied without interruption. In contrast, the use of storage systems in grid-connected solar installations, which are the norm for installations on private roofs and commercial businesses, is still a relatively new phenomenon. Electricity storage systems that are available on the market are suitable for use when retrofitting existing photovoltaic installations and can also be factored into the system design when planning new installations. All storage systems save excess energy and put it at the disposal of consumers at a later point in time.
If the operator knows that a storage system is required before construction works begin, the system will normally be integrated into the direct current side of the installation. This reduces investment costs, achieves a higher efficiency, and allows module output and storage capacity to be coordinated with each other in the system design.