On May 15, a fire broke out at Otay Mesa Gateway Energy Storage Station (lithium battery) in San Diego, California, USA. So far, the fire has reignited twice and has been burning for six full days, and there is no indication that the fire is about to be fully controlled.
On the afternoon of May 15, that is, last Wednesday, the 250 MW energy storage facility was found to be in fire for the first time. Since the fire, the fire brigade has been injecting water into the building's fire extinguishing system to suppress the flame and cool the hot batteries. It took the staff about 24 hours to control the fire and lift the evacuation order.
The initial fire was almost completely extinguished on the afternoon of May 16. However, the first rekindling occurred on the night of extinction. On May 17, the staff had ventilated the fire center area, and a fire officer said the situation was "relatively controllable".
On the evening of May 17, the second rekindling occurred, and more than 30 firefighters returned to work and tried to extinguish the fire. However, it didn't help. On Saturday night, the fire suddenly broke out, spread to building parts, and burned part of the roof of the storage facility.
At present, fire officials are still unable to accurately estimate how long the fire will continue. In an interview with local media, fire officials said it might take weeks to put out the fire.
"After talking with experts, they have encountered several similar incidents in the past, each lasting from seven days to several weeks, and we are not sure. We are preparing for the worst situation, and plan to stay here for a long time, two to four weeks, and then reassess." Brent Pascua, the leader of the San Diego Branch of the California Fire Department, said.
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It was the world's largest battery storage power station
This serious fire occurred in Building 3 of Gateway Energy Storage Power Station operated by Rev Renewables, a subsidiary of LS Power, a grid infrastructure developer in San Diego.
LS Power is a development, investment and operation company focusing on the power and energy infrastructure in North America. Since its inception in 1990, LS Power has developed, constructed, managed or acquired more than 42000 megawatts of power generation projects, including utility scale solar, wind, hydropower, natural gas power generation and battery storage projects, as well as more than 680 miles of transmission lines. LS Power has raised more than $45 billion in debt and equity financing to support infrastructure construction in North America.
On August 19, 2020, Gateway energy storage power station with an installed capacity of 250MW was officially connected to the grid.
"By charging during off peak solar power generation and delivering energy to the grid during peak power demand, our battery storage project has improved power reliability, reduced costs, and helped our state achieve its climate goals." John King, director of LS Power renewable energy, said at the press conference.
Gateway Energy Storage Station was the largest battery energy storage project in the world at that time. It used LG Chem lithium-ion batteries, covering 80000 square feet. This project broke the record of Australia's 150MW project supplied by Tesla before, although it has been surpassed by other facilities since then.
At that time, California was building a wave of large-scale battery projects, many of which aimed to replace the retiring natural gas and nuclear power plants by transferring solar power generation to a few hours after sunset. The Gateway is the first in the series to go online. It itself generates more power than any other battery connected to the grid managed by CAISO.
In recent years, with more renewable energy entering the California power system, energy storage projects have attracted more and more attention. (See details:)
In terms of operation, John King said that LS Power supports Gateway's business plan by selling energy products to power retailers and non-profit community energy providers. One of the products involves customers providing the remaining electricity at noon. Gateway promises to store and return this electricity at night, so that customers will be protected from the impact of soaring prices.
Gateway also won resource adequacy contracts (similar to capacity markets) with Pacific Gas Power and Southern California Edison.
In addition, Gateway also participates in all markets of CAISO.
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Worries about thermal runaway of lithium battery
The California Fire Department said the cause of the fire was still under investigation.
However, firefighters say these unpredictable fires are the result of a chain reaction of "heat runaway".
According to a report released on Saturday morning, the lithium-ion batteries in the warehouse "continue to experience thermal runaway", that is, the batteries enter an uncontrollable self heating state. When the rate of heat generation of lithium ion battery exceeds its heat dissipation rate, this reaction will occur, resulting in rapid temperature rise and fire.
As for why the fire broke out repeatedly, the fire department explained that it was difficult to put out such fires because lithium ion battery fires would produce oxygen. Therefore, although water-based fire extinguishers help cool burning batteries, they rarely completely extinguish fires.
"You must use water to extinguish the fire, but the water will damage the batteries and cause them to cause another fire. Historically, we usually see that this kind of chain damage will last for a longer time, almost like the domino effect." said Robert Reisende, battalion director of the San Diego Fire Rescue Bureau and emergency response coordinator for alternative energy.
In addition to the explosion, the possible toxic gas generated by the fire has also raised concerns.
The California Fire Department said that the hazardous materials team has arrived at the site to ensure that the air quality and water flow are not polluted.
"We are beginning to monitor the air again to make sure everyone can stay here safely. We have indeed issued an evacuation warning for the area. We will continue to monitor the air around this building," said Mike Conett, the head of the California Fire Department.
"These chemicals are really toxic, and you certainly don't want to have residents nearby. We are talking about one of the largest battery facilities in the world. We are talking about 216 40 foot long containers, each with lithium ion batteries," he added.
The official also explained that the staff wore "full equipment" and were equipped with full respirators to protect their lungs, skin and eyes.
