In homes, water is stored in reservoirs, tanks, or big drums for use during water shortages or droughts. This concept has a similar application in the energy space. The Battery Energy Storage System (BESS) is a storage device that stores electrical energy in rechargeable batteries for distribution at a later time. The BESS is an electrochemical application of energy storage systems. It finds application in standalone system solutions as well as hybrid technologies. It is essential to balance energy delivery, particularly through intermittent renewables like tidal, wind, and solar. BESS is more easily adaptable and is not location-specific compared to other energy storage systems.
A typical BESS consists of the following:
- Battery System: This is the key component of BESS. It consists of battery cells that collect and store electrical energy as chemical energy. In today’s world, most already built systems use lithium-ion batteries. A module is formed when battery cells are connected in series and parallel. Also, a rack is formed when the batteries are stacked. The racks are connected in series or parallel to achieve the desired voltage and current of the BESS.
- Battery management system (BMS): This component is critical in lithium-ion batteries. It serves as the battery system’s brain by ensuring its cells operate within safe limits and parameters. These parameters include state of health, voltage, temperature, current, and state of charge. The BMS uses this information to control and balance the battery’s environment.
- Control components: This is the “central processing unit” of the entire BESS. It manages the energy flow between the battery, the grid, and other power system components. It can integrate third-party BMS or supervisory control and data acquisition systems (SCADA) for energy management and data collection.
- Power conversion equipment: This component converts direct current (DC) in battery systems to alternating current (AC) that most electrical appliances can use. It is also known as a hybrid inverter. It allows the BESS to charge and discharge. By adjusting the depth of discharge and battery state of charge, BESS can also be set up to charge and discharge efficiently.
- Fire suppression: This component gives extra protection to the system. It releases an agent to absorb the heat and cool the system during thermal runaway.
The BESS has different applications, including but not limited to backup power, grid-scale energy storage, microgrids, and electric vehicles.
The benefits of BESS are that:
- It increases fuel efficiency and saves cost by serving as backup power.
- It increases energy efficiency by storing excess energy when energy demand is low for later use.
- It improves the quality of the power supply by assisting in load levelling and grid support.
- It helps balance out fluctuations.
- It allows for the integration of intermittent renewables into the grid.
The BESS also has its shortcomings. The BESS has a higher capital cost than other energy storage systems. There are issues around its performance and lifespan, particularly with lithium-ion. Also, the BESS is less reliable than conventional power generators.