The graphic illustrates two key points. First, most of the BTM (Behind The Meter) capacity injected into the system during the event was additive to regular daily operations. On July 28, BTM batteries never discharged more than 150 MW to the grid during the evening, far less than the amount recorded during the July 29 test. Second, the output from these disparate BTM batteries was consistent during the event, meaning the system operator could count on it just like any other generation resource.
In other words, BTM battery capacity can cut peak demand, reducing the need to invest in new peaking generation resources.