Demand peaked at 23,333MW, surpassing the previous record of 19,105MW set on March 13, 2014, the state planning ministry (Minplan) said in a release, citing data from wholesale power market regulator Cammesa.
The system had available backup capacity of 2,900MW when the new record was set, Minplan said, or 12.4% of the peak demand total.
Planning minister Julio de Vido last week dismissed concerns raised in the local press over the country's backup capacity margin in the wake of power outages in and around capital Buenos Aires.
The 2015 and 2014 peak demand records were set at 8:50pm and 8:26pm, respectively.
Total energy demand for Monday-Thursday reached 1,908GWh, up from 1,446GWh during the same period a year ago.