Off-grid systems and energy storage systems

While mentions of large tied-grid energy storage technologies will be made, this chapter focuses on off-grid storage systems in the perspective of rural and island electrification, which means in the context of providing energy services in remote areas. The electrical load of power systems varies significantly with both location and time.

If nonelectrical energy storage systems—such as water tank for a pumping system or flywheels or hydrogen storage in specific locations and contexts—are sometimes a relevant solution, electrochemical storage technologies are the most common for off-grid installations [35 ].

Electrochemical energy storage is indeed the most common storage option in off-grid projects, although a few hybrid storage systems have emerged during the past few years. Key parameters used to compare the types of batteries on the market are described below ( [2, 25, 26 ]):

1. Introduction: the challenges of energy storage Energy storage is one of the most promising options in the management of future power grids, as it can support the discharge periods for stand-alone applications such as solar photovoltaics (PV) and wind turbines.

Energy storage systems allow energy consumption to be separated in time from the production of energy, whether it be electrical or thermal energy. The storing of electricity typically occurs in chemical (e.g., lead acid batteries or lithium-ion batteries, to name just two of the best known) or mechanical means (e.g., pumped hydro storage).

For minigrids and off-grid systems, energy storage technologies become a must when the renewable penetration is high, especially with no backup diesel engine. On the other hand, RE sources injecting energy into the grid when the demand is low constrains operators to store, export, or lose the produced energy.