Widespread blackouts in Mexico earlier this week hit 21 states and sent the electric power system into emergency status – but the natural gas market was largely unimpeded.

Power system operator Cenace said the failures on Tuesday (May 7) were caused by soaring demand amid scorching temperatures. Some Cómision Federal de Electricidad (CFE) natural gas combined-cycle plants, including Altamira and Villa de Reyes, went offline because of load shedding as the reserve margin dropped below 3%.

Cenace officials called it an “atypical situation” with power demand hitting close to 50 GW. Operational alerts were also issued on Wednesday and Thursday with additional power outages reported.

Mexico President Andrés Manuel López Obrador said the blackouts happened because “heat...