Less than 5 months apart! The world's largest energy storage power station in the United States is on fire again! The battery equipment manufacturer is LG

　　On the evening of February 13, another accident occurred at the Moss Landing energy storage power station project in California, and about 10 battery racks were melted.

　　This is the second incident at the project in the past five months. On September 4, 2021, the project had a battery overheating accident. Firefighters said the two incidents provided a lesson for all parties to make any necessary adjustments or improvements.

　　SES Power has rich experience in customizing lithium battery systems. We are very concerned about the safety issues in the application of lithium batteries, especially with the acceleration of the global energy conservation and emission reduction process, clean energy (wind power, hydropower, photovoltaic power generation, etc.), the energy storage industry has ushered in explosive growth. This means that there are more and more potential fire hazards. We cannot learn with fresh life. We must effectively formulate and popularize the fire protection standards and knowledge of battery energy storage systems, especially large-scale lithium-ion battery systems.

　　(Aerial view of the energy storage power station, natural gas power plants have been replaced by emission-free lithium battery technology)

　　The owner and operator of the project is Vistra Energy, the battery equipment provider is LG Energy Solution, which just went public, and Fluence is the system integrator and engineering contractor. The project site is located in Moss Landing, Monterey County, California, USA. It was originally a natural gas power plant owned by Vistra Energy and was replaced by an energy storage power plant.

　　The facility's primary purpose is to help California reduce power shortages during nighttime rush hours and replenish electricity during the day from the state's cheap and abundant solar PV generation, which is released when the grid needs it most. The energy storage power station started operation on December 11, 2020. When it was completed, it was the world's largest battery energy storage system (BESS), including 300MW/1200MWh lithium-ion batteries. When the energy storage power station is running at full capacity, it can supply power to 225,000 households for 4 hours.

　　LG New Energy revealed that the factory has installed more than 4,500 battery racks, and it is the latest model TR1300. LG says the TR1300 battery racks are factory pre-assembled before shipping, which reduces construction time and installation costs. Equipped with JH4 high-energy batteries, the TR1300 racks can be installed into the existing turbine halls of the Moss Landing power plant due to their ability to double stack, minimising construction work.

　　(Part of 4,500 battery racks at Moss Landing Energy Storage Station)

　　LG New Energy said the TR1300 has been tested according to UL 9540A thermal runaway fire spread standard, and the rack design meets California Building Code requirements, which are considered safe to operate when the perimeter is threatened by seismic activity.

　　Moss Landing also previously had a huge battery energy storage system called Moss Landing BESS. The energy storage capacity of the project is 182.5MW/730MWh, and the equipment is provided by Tesla.

　　Vistra Energy said in June 2021 that if market and economic conditions permit, the scale and capacity of the Moss Landing energy storage plant may subsequently be expanded to accommodate up to 1,500MW/6,000MWh of energy storage.

　　However, as soon as the words fell, the project encountered an accident.

　　On the evening of September 4, 2021, the first phase of the Moss Landing project caused losses to about 7% of the battery modules and other system equipment in the project due to the activation of the battery's water cooling system. The accident did not cause casualties or affect the surrounding communities.

　　After the accident, Vistra, the operator of the project, together with external experts, conducted a five-month investigation into the accident and formulated a rectification work plan for the project, which is planned to be fully implemented before the project restarts.

　　The findings revealed that at approximately 18:41 on September 4, the VESDA unit detected smoke near containers 64, 57, 47 and 41, causing the release of water in pre-action zone 24 and preventing the passage of the affected container. The current flow of the container (an automated process called E-Stop). Due to an apparent programming error in VESDA, these actions occur when the detected smoke level is below the specified design level, at which point the water is released and the E-Stop is activated.

　　During the first release of water to the cooling system, the temperature of all battery modules was recorded within a set temperature range, well below levels that would indicate thermal runaway. Therefore, the investigation concluded that the battery module was not the source of the smoke.

　　At the time of the accident, a small number of fittings on hoses and pipes that were part of the battery cooling system failed, causing water to spray onto the battery racks. This in turn leads to short circuits and arcs, which can lead to battery damage and more fumes.

　　These additional fumes are detected by other VESDA equipment, causing water to be released into other preaction zones, followed by hose/pipe failure, releasing more water, causing more damage and fumes. Vistra was unaware of any fire in the building and the original fire suppression system inside the building was not activated.

　　Overall, about 7% of the mods were damaged to varying degrees, and other facility systems were also damaged. This damage is caused by water released from the cooling system and the resulting short circuits and arcs. Part of the water is sprayed directly onto the battery rack, and part of the water leaks to the lower battery rack through the upper gap.

　　The preaction headers and pipes on each battery rack are individually pressure tested before they are connected to each other. However, Vistra was unable to confirm whether the contractor pressure-tested the entire cooling system after connecting the racks to the headers. Most of the failures were on the hoses connecting the rack to the header, apparently not pressure tested.

　　Less than 5 months later, the project caught fire again, and Vistra Energy subsequently issued a statement, "Late February 13, the Moss Landing Project Early Detection System was activated, and as we have agreed at all facilities, out of an abundance of caution, we have contacted off-site emergency response and there were no casualties at the scene. An investigation is ongoing to determine why the security systems were activated and we will share more information as we learn more about the situation."

　　From the analysis of Vistra Energy, it can be concluded that the design of the surrounding of the lithium battery has caused the safety hazard of the lithium battery system. SES Power has rich experience in lithium battery packs for energy storage systems. It is recommended that customers use lithium iron phosphate batteries first, such as 12V100Ah, 12V200Ah, 24V100Ah, 48V100Ah and other modular lithium batteries. We will increase the safety of the battery according to the actual situation. Protection is not only about the electronic structure, but also needs to be comprehensively dealt with in terms of mechanical mechanisms, destructive shocks, etc. The more comprehensive the system is considered, the higher the safety of lithium batteries.

　　The ternary lithium battery with high energy-to-volume ratio has more energy than lithium iron phosphate battery, but the safety is superior to lithium iron phosphate, so SES Power recommends using long cycle life and high safety in the energy storage system as much as possible. Lithium iron phosphate battery.