I wonder if this might be misleading. A lot of Los Angeles’ (LADWP) electricity has traditionally been generated generated by coal-fired plants in other states. I’d have to dig into more recent sources to see if that’s still the case, and whether that’s reflected in this dataset.

(Edit: read the sources list, and that should be reflected, but the map is not displaying heavy imports to SoCal. If I had to hazard a guess, I’d suspect LADWP obscuring sources in the published data).