PG&E restarts huge grid battery following Moss Landing fire next door

Yahoo

2 days ago

One of the biggest grid batteries in California has resumed operations following the cataclysmic Moss Landing fire in January.
The San Francisco Bay Area's power grid used to draw on two battery storage plants in the quiet seaside town of Moss Landing. Texas-based power company Vistra built the nation's largest standalone grid battery on the grounds of an old gas power plant there, and utility Pacific Gas and Electric Co. built and owns the Elkhorn project next door.
A roaring fire engulfed Vistra's historic turbine hall in January, wrecking rows of lithium-ion batteries that delivered 300 megawatts of instantaneous grid power. That site is still in shambles. PG&E's battery plant suffered far less disruption: Hot ash blew over the fenceline from Vistra's property, posing an environmental hazard and potentially clogging batteries' thermal management systems. But after several months of remediation, cleaning, and testing, PG&E was able to flip the switch Sunday to reconnect Elkhorn to the grid.
That timing proved fortuitous, as it restored 182.5 megawatts/730 megawatt-hours of storage capacity into the power-hungry Silicon Valley grid corridor right before the region's first major heat wave of the summer.
'The concern was lower in the winter months, with demand lower,' said Dave Gabbard, vice president of power generation at PG&E. 'It will be critical to have assets like Elkhorn available as we get into the peak summer months.'
Indeed, California has been building grid batteries at a record pace, to store the state's nation-leading solar generation and deliver it during crucial hours, like after sunset. The tech is displacing some gas-fired power generation in the state. California's battery fleet passed 15.7 gigawatts installed per a May tally, which Gov. Gavin Newsom's office touted as 'an unprecedented milestone.' The governor, a Democrat, did not specify why the 15.7-GW threshold merits particular attention, but it does mean California has added more than 5 GW since it crossed the 10-GW mark a year prior.
'The pace of construction for large-scale energy storage in California is phenomenal, the kind of accomplishment that was beyond our wildest dreams a few years ago,' said Scott Murtishaw, executive director of the California Energy Storage Alliance.
The state's battery buildout is plowing ahead. But Vistra's fiery failure sparked deep community concerns about battery safety in California and beyond, as Moss Landing residents were forced to evacuate for several days and plumes of smoke loomed over surrounding estuaries and farmlands. In April, Vistra rescinded an application to build a 600-MW battery in Morro Bay, two hours down the coast from Moss Landing, following significant local resistance that intensified after the January fire.
The reset at Elkhorn has rekindled concerns among community leaders who are still grappling with the fallout from the largest-ever battery fire in the U.S., and quite possibly the world. The Monterey County Board of Supervisors had asked to keep both battery plants offline until the Vistra investigation was completed and acted upon.
'Restarting operations before investigations are complete and before stronger emergency protocols are in place is disappointing and deeply troubling,' Monterey County Supervisor Glenn Church posted on Facebook after learning of PG&E's plans in early May.
Crucially, PG&E's battery layout, completed in 2022, mitigates the hazards that took out the neighboring Vistra plant, which was completed two years earlier.
Officials have not yet pinpointed the cause of Vistra's fire, but it became so destructive because it spread through the densely packed rows of batteries in the old turbine hall, igniting more and more fuel as it grew. By contrast, PG&E's Elkhorn plant spans 256 individual Tesla Megapack containers spaced over the property.
'We have a completely different design,' Gabbard said. 'We have compartmentalized our design so that fire propagation won't occur to adjacent units.'
That industry-wide preference for separate, containerized systems doesn't eliminate the chance of battery fires, but it does limit the potential severity. One container might burn, but the fire can't reach all the other batteries. A fire could knock a facility offline temporarily, but it would only eliminate a small percentage of its capacity, Murtishaw said. That stands in contrast to Moss Landing's failure, or the all-or-nothing issues that can occur when a gas-burning turbine malfunctions.
'The technology and standards have changed considerably since the first big batteries,' like Vistra's, Murtishaw said. 'Facilities coming online now are being constructed with newer technologies meeting newer standards. Risk of runaway incidents has decreased dramatically relative to the amount of storage being deployed.'
That compartmentalization strategy worked out when Elkhorn suffered its own battery fire in 2022 — the result of water seeping into a unit through an improperly installed roof, Gabbard said. The single unit burned in a contained fashion and did not spread to any other batteries. PG&E restarted the facility three months later, after implementing recommendations from an independent investigation into the cause.
Since that incident, PG&E installed air quality monitoring onsite, and heat-sensing cameras that can automatically disconnect the site from the broader grid if they detect fire, Gabbard said. It also upgraded the battery enclosures to automatically discharge stored energy if abnormal behavior is detected. PG&E additionally updated its emergency action plan and instituted annual exercises with the North County Fire Protection District.
When Vistra's plant burned up in January, the Elkhorn cameras spotted it and automatically severed the connection to the grid, halting the flow of high-voltage power out of the site. PG&E also made the air quality data available to emergency response teams.
The utility then kept Elkhorn offline for the subsequent months to allow for environmental remediation of the soot to keep it out of local waterways, Gabbard said. Workers also cleaned the Megapacks 'outside and inside,' he noted. The main concern was that the ash could have intruded into the systems that cool batteries during operations. Staff pressure-washed all those components and tested their functionality to get the site ready for operations.
Another 10 gigawatts of storage are already under contract for California's regulated utilities and community choice aggregators over the next four years, Murtishaw said. That would put the state over 25 gigawatts, well on its way to the current goal of 52 gigawatts by 2045, stemming from the state's clean energy law SB 100.
To achieve that goal, the Moss Landing calamity needs to remain an outlier event. There's good reason to believe that will be the case. For one thing, the industry has all but abandoned Vistra's strategy of packing huge amounts of batteries into a single building.
California now has 214 grid-scale batteries, and only about 10 of them reside in a building, Murtishaw noted. Those are subject to inspection by the California Public Utilities Commission under a recently expanded authority, he added; in the meantime, owners have stepped up safety measures in response to the Moss Landing news.
Small-scale batteries in homes and businesses also count for California's top-line storage goal. They depend on the same core battery technologies as the large-scale storage projects, but as mass-produced consumer items, they go through a different gauntlet of tests before they reach customers.
'The home batteries are tested inside and out, up and down — they undergo rigorous safety testing and certification to standards,' said Brad Heavner, executive director of the California Solar and Storage Association, which advocates for rooftop solar and battery installers.
In the state Legislature, Sen. John Laird, a Democrat from the Moss Landing area, introduced a bill in March to systematize coordination between battery owners and local emergency responders, and to fix a timing mismatch so California's fire codes match the latest standards set by the National Fire Protection Association. Murtishaw said the California Energy Storage Alliance supports the measure, which passed out of the Senate last week.