California just watched its most extreme September heat event in history and survived better than expected – thanks in part to a new system of huge grid-connected batteries.
The severity and duration of this latest climate-induced heat has challenged the state’s power grid like never before, setting records for electricity demand that have pushed supply to its limits. But the system held. The lights stayed on.
Additional testing is forthcoming, for California and other states and nations. But after this cycle, California has a clear lesson for the world: battery storage is a powerful tool for networks facing new stresses from heat, cold, fires, floods, or aging networks. And just as important, batteries are the key to the zero-carbon future we need to avoid even greater stresses down the line.
Californians delivered big time this month when asked to cut consumption at critical times in the crisis. But without the storage capacity of the new battery systems, the reduction in demand might not have been sufficient and many consumers would have faced painful outages.
To be clear, the batteries that saved California this month aren’t like the ones in your phone, tablet, and laptop, or even the biggest batteries in some homes ready to supply power for failures. The batteries that saved California are big – big industrial. Individual units weigh tens of thousands of pounds and entire systems can be larger than a football field.
Many are installed in utility-scale solar fields, while “stand-alone” systems are strategically located throughout the state. They are not small additions to our power grid — they act as large power plants. In fact, some of the largest batteries literally occupy real estate and buildings that once housed fossil fuel generators. And California has more batteries than anywhere else in the world, having grown its fleet more than 10-fold in the past two years alone. Altogether, California’s batteries are now its largest power plant.
For the vast majority of the year, these batteries play a critical role in stabilizing the grid, smoothing power flows, and balancing variable power. They also play an important role in leveling wholesale energy prices by recharging when electricity is cheap – typically during the midday “solar peak” – then offloading the energy to the grid later in the year. day when prices are higher, a practice that keeps the market in check and reduces energy costs for Californians. But at the start of this month, these batteries went from everyday workhorses to crisis saviors.
During a critical peak on the evening of September 5, as the grid rapidly approached capacity, California batteries provided more power – more than 3,360 megawatts – than the Diablo Canyon nuclear plant, the largest generator state power plant, which peaks at 2,250. From 5:45 p.m. to 8:45 p.m. that Monday, when threats of mandatory outages were at their peak, state batteries pumped out 2,000 megawatts or more continuously in the network, i.e. three full hours of energy saving on the network. The batteries provided approximately 4% of supply during peak demand, helping to avoid power outages.
No power grid in history, anywhere in the world, has experienced such a thing. When the state experienced an electricity crisis during an August 2020 heat wave, power outages occurred over several days, leaving many Californians in the dark, without electricity for cooling and d other basic needs. At that time, California’s grid-connected power plant batteries were few and small, and provided an average of only 50 megawatts of electricity for two hours.
What a difference two years have made – an amazing difference that challenges what most energy experts think they know. But the numbers are there. In just two years, California has strategically built a battery bank capable of self-discharge 150 times more energy at the height of the crisis on September 5 than the batteries on August 14, 2020.
And the batteries are just getting started. Every month more and more battery systems are connected to the California grid. Over the next few years, the state battery fleet will more than double. Every new large-scale solar project is now installed with batteries, making all new solar power “dispatchable”, meaning power can be used when it’s needed most and not just when the sun is shining. In fact, much of the energy distributed by the batteries during the critical evening hours of the last California power crisis was solar energy stored earlier in the day.
Due to unprecedented declines over the past decade in the costs of solar panels and lithium batteries, more dispatchable solar storage is now beating new fossil fuel power plants on the cost of electricity.
None of this happened by accident. California began investing in solar energy more than 20 years ago and passed Assembly Bill 2514, the first legislative term for grid energy storage, in 2010. Governor Gavin Newsom also pushed for more clean energy assets on the state grid. These long-term efforts are paying off for California and have shown the world what is possible.
Mike Ferry is director of research at the Center for Energy Research at UC San Diego.
Los Angeles Times