Know your data sources.

ONS (Operador Nacional do Sistema Elétrico) — Brazil's national electricity grid operator. Public Tempo Real REST/JSON feed, no credentials. Real-time national system load (SIN, ~77 GW), generation mix by source (hydro, thermal, wind, solar, nuclear), marginal operating cost (CMO) by submarket (Southeast/Center-West, South, North, Northeast) in R$/MWh, the energy balance snapshot (generation, load, import/export and interchange by submarket plus international ties with Argentina/Paraguay/Uruguay), and reservoir energy storage (EAR). Joins the power-markets family (ercot/spp/nyiso/caiso/aemo/cammesa/eirgrid).

CAMMESA is Argentina's wholesale electricity market and grid operator (SADI). This connector exposes real-time, public demand and temperature for the 24 provinces and 8 regions plus the system-wide total, refreshed every 5 minutes (today, yesterday, same-day-last-week, and the dispatch forecast), and the live generation mix by fuel (hydro, thermal, nuclear, renewable, imports). No setup needed.