Largest Grid Battery Ever? What’s the Real Story?

Posted on Posted in Master Metered Residential

Southern California Edison has announced, apparently, that they have applied to the DOE, under the smart grid stimulus program, for $25 million to build the largest grid battery ever. I have many questions about this story and I’m hoping we’ll get more clarification in the near future.

We are well aware of the DOE grant program because we are involved in several applications for the VRB-ESS. We’ll provide more information as we have developments we can share.

Here are the issues and questions I have with the story:

  • First, I cannot find a press release from SCE. The story appears to based on an interview with Paul De Martini, Southern California Edison’s vice president of advanced technologies. This makes it a bit difficult to get more detail or clarification. We’ll ask Mr. De Martini for clarification.
  • Next, the story says the grant is for 32 megawatt hours of storage. Since the current A123 grid systems in place are for grid stabilization, with only about 15 minutes of storage, Edison would need to install 128 MW of capacity to get 32 hours of energy. That would make it a huge, unheard of capacity battery, but with very short term storage. So, I’m not sure what the application would be for wind energy. 4:1 capacity to energy storage is normally conceived for frequency regulation, which is the current application for A123. That type of application can be anywhere on the grid – there is no need to place it at a wind farm. We normally think of storage for wind for the purpose of shifting generation from night time production to the day – something you can’t do with 15 min. of storage.
  • If the project is 32 MWHrs of storage, then it isn’t the biggest project by a long shot. The 238 MWHr system by NGK in Japan wins that contest with their 34 MW by 7 hours of storage system. Sure, they can only use half the capacity at a time to avoid overcharging, but the total is still greater than the Edison project – if the story is correct.
  • The ARRA grant is a matching grant, so we assume Edison will need to seek approval from the California Public Utilities Commission for an additional $25 million, or more, for a total cost of $50 million. That’s $1,500 per kilowatt hour! – pretty darn expensive. For comparison, the flow batteries and NGK are between $500 and $700. However, on a capacity basis, at 128 MW, it’s only $390 per kW.
  • If the story meant to state a 32 MW capacity, then the economics make no sense.

I think the actual story is that Edison wants to install a large capacity system for grid stabilization, not an energy storage system to shift wind generation. Does it make sense? A 120 MW VRB-ESS with 6 hours of storage would cost around $300 million – 6X more expensive. However, along with fast response like the A123, you would also have 720 hours of energy storage! Is a 15 minute, fast response battery going to do the job, even if it is cheaper? This will be interesting to get the rest of the story and see how Edison presents the project to the CPUC.

One thought on “Largest Grid Battery Ever? What’s the Real Story?

  1. I have my sources – I just learned, from a knowledgeable source, that the configuration is 8MW for 4 hours. I'm not familiar with this configuration so I remain eager for more details…

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