CAMMESA administers the Argentinian electricity market, and they have data on demand [1] and grid flows. Compare the graph of flows on the 500 kV lines from 2019-06-16T07:00 local [2] to one hour later at 08:00 local [3]. For reference, see the prior day too, at 2019-06-15T08:00 local [4].
[1] http://portalweb.cammesa.com/Pages/ADemandas.aspx [2] http://www.cammesa.com/uflujpot.nsf/FlujoW?OpenAgent&Flujo%2... [3] http://www.cammesa.com/uflujpot.nsf/FlujoW?OpenAgent&Flujo%2... [4] http://www.cammesa.com/uflujpot.nsf/FlujoW?OpenAgent&Flujo%2...