Earlier this week Scientific American reported that AES Corp. has been awarded a contract to supply the world’s largest storage battery to Southern California Edison.  The battery, which will use lithium-ion chemistry, will be capable of holding and delivering over 100 megawatts of power an hour for four hours.  The battery will replace a traditional gas “peaker” plant, helping Southern California Edison accommodate peak loads in the West Los Angeles area.  The plant will come on line in 2021.

There are two parts of this story that are remarkable.  The first is that Southern California Edison’s purchase of battery energy storage to do large scale power shifting indicates that the economics and the technology of battery energy storage have arrived at a place that was nearly unimaginable only a few years ago.  Using batteries to provide fast response frequency regulation or to manage demand charges in certain discrete markets has been profitable for the past few years.  But the point where it would be more economic to arbitrage electric power, by storing it off peak and discharging it on peak, than to generate it using cheap natural gas, had seemed far off, at least, perhaps, until this week.

The second noteworthy aspect of this story is that AES Corp. is using a lithium-ion battery to do this 100 megawatt, 4 hour power shifting, rather than another type of battery, which might technically be more suited to that application.  Certain types of flow batteries come to mind as potentially more suitable technologies.

Southern California Edison’s decision illustrates a principle that I have written about previously in this column:  in battery technology, experience generally trumps performance.  For whatever the shortcomings of lithium-ion batteries, they are using their market penetration in the consumer and automotive spaces, to build credibility in the stationary energy storage (ESS) market.  According to a report from Navigant Research, lithium-ion accounted for more than half of newly announced ESS capacity and more than 85 percent of deployed ESS power capacity in 2015.

Next Wednesday at the Intersolar/ees North America conference in San Francisco, NAATBatt will produce a workshop focusing on the relative strengths and weaknesses of the different types of battery energy storage available to developers of ESS projects today.  The workshop will be a unique opportunity for developers to compare and contrast those different technologies based on their technical merits.

But the bigger question for non-lithium-ion battery manufacturers is: does it matter?  I suspect that the next few years will provide a chance for other technologies to compete with lithium-ion technology in ESS applications and to try to capture market share, and market momentum, from it.  But the door to that opportunity may be closing rapidly.  I look forward to a spirited discussion about that question at next Wednesday’s workshop.  I hope you can join us.