Moss Landing battery energy town hall gives locals a chance to ask questions

SALINAS – About 100 attended a Moss Landing Lithium-ion Battery Energy Storage System Facility Town Hall last week where the Vistra and Pacific Gas and Electric/Tesla facilities operating at the Moss Landing power plant were discussed.

Recent events concerning overheated batteries at each facility and the response to those incidents were much talked about.

In addition to those in attendance at the Castroville meeting were about 50 who watched the livestream. Monterey County District 2 Supervisor Glenn Church, State Senator John Laird, Assembly member Dawn Addis, and other officials, as well as representatives from the two power companies were on hand to talk about the facilities, past incidents, how those incidents were handled, and to hear questions from concerned citizens.

“There is no higher priority at Vistra than the safety of the communities we serve, our people, the environment, and our company sites,” said Cynthia Vodopivec, Vistra senior vice president for environmental health and safety. “That commitment to safety will extend through the design, construction, and operation of the Moss Landing battery energy storage system.”

Vodopivec explained that there is inherent but manageable risk in all forms of generation, transport and storing of energy and all energy sources have experienced events. In a lithium-ion battery energy storage system, thermal runaway is a rare internal electro-chemical reaction that releases heat and occurs when the voltage or temperature inside the battery becomes unstable.

“Codes, rigorous standards and operational best practices are leveraged to reduce these risks through prevention, detection and mitigation,” said Vodopivec.

Vistra had incidents that occurred at its battery energy storage system Sept. 4, 2021 and Feb. 13, 2022. Pacific Gas and Electric/Tesla, also known as Elkhorn Battery Energy Storage System, had an incident  Sept. 20, 2022.

Vistra has completed three of four phases of its battery energy storage system and will ultimately provide enough energy to power more than a million homes. The Elkhorn Battery Energy Storage System could also be expanded beyond its current ability to provide enough electricity to nearly 275,000 homes.

Coincidentally, the PG&E/Tesla incident occurred a year prior to last Wednesday’s town hall. That event closed Highway 1 in both directions and prompted a shelter-in-place order for the surrounding area. The move was due to the possibility the smoke from the event could contain toxins from the burning lithium-ion batteries.

The “Elkhorn Battery Energy Storage System event of Sept. 20, 2022, (occurred) when a single battery storage container called a Megapack experienced a thermal event,” said Dave Gabbard, PG&E vice president of power generation. “Today is the one-year anniversary of the event. While a lot of our design components to the site operated as intended, the fire was self contained, didn’t propagate, burned itself out, and was safely managed on premise. There were a number of learning (experiences) that we had through the event.”

Gabbard said a root cause analysis investigation revealed the cause was due to an equipment installation issue that resulted in water ingress which caused the battery cells to overheat. An improperly installed vent shield dislodged an umbrella valve on the top of the Tesla Megapack, causing an unnatural water ingress point due to rainfall.

The investigation identified that 88 megapacks (out of 250) in total experienced water intrusion as a result of the improperly installed vent shield, but only one resulted in a thermal event. All 88 megapacks have been inspected, and any damaged parts have been replaced and tested and re-tested.

“The thermal runaway occurred in a unit located near several other megapacks, but as designed the thermal runaway did not propagate and grow into a larger issue,” said Gabbard. “Different from our Vistra counterparts on site, the fire mitigation strategy for our megapacks is to self burn and self extinguish as opposed to introducing water into our electric infrastructure.”

Both Vistra incidents at its Moss Landing facility in 2021 and 2022 were caused by water leak events from its mitigation system. This led to grounding, arcing and localized smoke.

“The mitigation system is a series of nozzles that have the ability to inject water into the battery modules themselves,” said Brad Masek, Vistra director of renewable operations. “The goal of that is if a battery is in distress and in the thermal runaway early stage or in the incipient stage, we can detect it and shut it down and deploy the water if needed.”

Both the Vistra events were contained to the site and did not impact air, water, soil, or nearby communities, said Masek. Vistra worked closely with the regional water board to develop runoff water containment, sampling, screening, and handling procedures. It was given approval for runoff water discharge through the normal stormwater conveyance system. Corrective actions were implemented to resolve water leaks and enhance the detection and mitigation systems.

At the time, both Vistra I and II were shut down while corrective actions were performed prior to restarting the facility including replacing all quick-connect fittings with threaded connections, pressure testing the complete heat suppression system with air and water, changing the system to a dual interlock design, which requires both smoke and activation of battery module sprinkler head to release water to heat suppression system that should eliminate activation of system by smoke that is not associated with battery overheating. Smoke detectors were installed in all air handling units to detect any smoke generated in air handling units or outdoors.

“Those lessons learned and those corrective actions were deployed in conjunction with our local officials,” said Masek. “We spent a lot of time discussing, informing and teaching, all the first responders in ensuring that we had a cohesive response to the events.”

Both the Vistra Moss Landing BESS and the PG&E/Tesla BESS use similar lithium-ion batteries but one chemical difference is the LG-supplied Vistra batteries use lithium-ion, nickel, manganese, and cobalt, while the Tesla-supplied PG&E batteries us a lithium, nickel, and manganese blend.

The hazardous materials within smoke plumes from lithium-ion batteries are two components of concern — carbon monoxide and hydrogen fluoride. According to officials with the county and PG&E, the hazard risk was hydrogen fluoride.

During the PG&E Elkhorn Battery Energy Storage System incident, the shelter-in-place order and Highway 1 closure was a joint decision with first responders and those on site that day. It was done in an abundance of caution and safety and lifted only after air sampling and the risk to the community was assessed.

Breathing hydrogen fluoride can damage lung tissue and cause swelling and fluid accumulation in the lungs (pulmonary edema), according to the Centers for Disease Control and Prevention. Skin contact with hydrogen fluoride may cause severe burns that develop after several hours and form skin ulcers. Hydrogen fluoride gas, even at low levels, can irritate the eyes, nose, and respiratory tract.

Chief Joel Mendoza of the North County Fire Protection District said that both companies have provided training for the local fire department.

“We have had the training and unfortunately we’ve had three incidents … and we’ve learned from each one,” said Mendoza. “We can do much better, and after each one we sat down with each company and have gone over all issues identified during the response and looked at how to improve response and public safety.”

The Moss Landing power plant site has been producing energy by various means since 1950. It has the infrastructure and zoned land that makes it a prime location for battery energy storage systems. The energy storage facilities exist there after going through the public process and were approved by commissions and boards before construction and operation. But it is a new technology that is evolving.

“I introduced SB38 with my one coauthor, Assembly member Adddis, who was supportive, that basically said ‘battery energy storage facilities located in the state of California and subject to specified safety requirements, have to have an emergency response plan, an emergency action plan, that covers the premises of the battery energy storage facility,’ ” said Laird. “Further, I took amendments that said those plans have to be presented to the city and/or county in which that battery energy storage facility is operated or constructed. And it was my goal to have there be a statutory requirement to do safety looking outward that involves the community in the discussion before it is ever an issue.”

SB38 is on Gov. Newsom’s desk awaiting his consideration and signature.

Addis said that along with Sen. Laird, she represents two battery energy storage projects – the existing one at Moss Landing and a potential one in Morro Bay at its power plant.

Addis said she sees where California, the state legislature, the Governor, and the industry is going and that is in a direction of historic investment in climate action, environmentally-safe lithium production, more battery energy storage projects, and other kinds of renewable projects.

“But what that says to me is that we need historic effort in making sure these projects are safe, because our communities have to feel that when they’re bearing the responsibility of climate action, they are also being taken care of,” said Addis.

Other county officials in attendance or gave presentations were Kelsey Scanlon, director of emergency management for Monterey County, Ric Encarnacion, Monterey County director of environmental health, and Chief Jason Smith, Monterey County Sheriff’s Office.

Go to, https://www.facebook.com/MontereyCoInfo/videos/3417272045251476, to view the Moss Landing Lithium-ion Battery Energy Storage System Facility Town Hall.