Here is a site which posts discharge data from the Tesla BigF'nBattery. There are often 30MW peaks. But never any real amount of area under the graph.
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NemWeb
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So I am still surprised to see only 8MW reported in a real emergency drop out of 560MW. And the other thing to remember is the scale of what we are trying to replace. Even if the BFB could maintain 30 MW for 4 hours and make it's rating, which it has yet to do for more than a few minutes, this is still only 5% of a small coal plant that we are trying to replace and only for 4 hours. We would need 120 BFBs just to make up for the output of that 1 plant for 1 day.