BESS can be connected to the power grid in basically two ways. They can in fact store electricity only from the renewable energy plant to which they are connected or from both the plant and the power grid. In the second case, battery systems also perform a function as regulators of the power grid. BESS always include inverters, which transform the direct current produced by the renewable plants into alternating current used for transport along the grid. A typical Fengau's BESS also includes a temperature management system for the site where the batteries are stored, management systems that continuously monitor voltage, temperature, any alarms, and state of charge, and even software tools, such as EMS (Energy Management Systems) that control battery charging and discharging.