BESS: Power Reserve for Energy Security in the Renewable Energy Era
13 August 2025
Over the years, the technology for electricity generation from renewable energy, which is considered clean energy, has grown rapidly across the world; combined with the pressure from environmental problems, renewable energy has become a key player in the global energy transition. However, renewable energy is not reliable and each passing day increases its impact on the security and stability of the power system. This is one of the challenges that every country must face amid the energy transition by finding ways to deal with the limitations. “What technology will help increase power system security as quickly as possible?”
Unpacking BESS
While aiming for clean energy transition, Battery Energy Storage System, or BESS, has become an important device for energy integration. It increases the stability of renewable energy which is often fluctuating and not consistent. Therefore, BESS is one of the technologies the Electricity Generating Authority of Thailand (EGAT) uses to help enhance power system security. BESS utilizes lithium-ion battery which has several notable features, such as rapid electricity supply within milliseconds (ms), lightweight, long lifespan of over 10 years. It is installed in a container with air-conditioning, making it similar to an energy box. It also takes up little space and can be used for various objectives, including supporting renewable energy. BESS helps store surplus energy to be used when there is no sunlight or wind, enabling maximum use of renewable energy and increasing the stability of the power system. This is immensely beneficial for maintaining the overall security of the grid (Grid Scale). Inside BESS are battery cells, power converter, power control and management system, and various security systems to provide the most stable energy reserve.
BESS Supplies Fast, Powerful Energy to Strengthen the Grid
BESS is comparable to the grid’s enormous power bank that can respond to fast-changing electricity demand and immediately supply electricity when there is an increase in demand. The principle behind BESS is that it stores energy during a certain period of time to be used at another time when there is demand. The battery is charged during low demand and then discharged to the system during high demand (Energy Shifting). It supplies electricity when renewable energy is fluctuating, controls the voltage (RE Firming), and compensates for the imbalance between capacity and demand in order to control and maintain the standard electrical frequency (Frequency Regulation), as well as help with Transmission Congestion Management by preventing the system from exceeding its capacity limits. Applying BESS to the power system enables maximum efficiency of renewable energy usage and enhances grid capability to securely support the increasing renewable energy (Grid Modernization).
EGAT Installs BESS to Supply Electricity to the Grid
Presently, EGAT has installed BESS at various locations:
1. Bamnet Narong Substation in Chaiyaphum Province with the capacity of 16 MW (battery capacity of 16 MWh)
2. Chai Badan Substation in Lop Buri Province with the capacity of 21 MW (battery capacity of 21 MWh)
At both substations, BESS is connected to the grid in areas with a large amount of electricity generation from renewable energy to support the fluctuating renewable energy in the area
3. Smart Grid Project in Mae Hong Son Province which has installed a battery with the capacity of 5 MW (battery capacity of 6 MWh) operating in conjunction with solar cells and the Smart Grid system to supply electricity to Mae Hong Son District for increased stability.
In the future, when the proportion of renewable energy in Thailand’s power system increases, BESS will become even more important for controlling the quality of electricity in real time as well as enhancing grid flexibility. However, installing BESS still involves high cost; therefore, BESS must be installed at suitable locations coupled with the development of other Energy Storage Systems (ESS), such as pumped-storage hydropower plant and hydrogen energy storage, which will help increase the stability of electricity generation from renewable energy, enhance Thailand’s power system security, and support the pursuit of Carbon Neutrality and Net Zero Emissions.