As Sun Sets, Mexico's Electrical System Faces Renewed Strain

Mexico's National Electrical System (SEN) is operating under intense pressure that does not subside when the sun goes down. On July 20, the National Center for Energy Control (CENACE) recorded a gross demand of up to 48,115 MW shortly before midnight, only 2.5% below the day's peak levels. Normally, electricity demand decreases at night, but the current heatwave compels more homes and businesses to keep their air conditioning running longer.

This sustained high demand strains the system's capacity. In April, then-CENACE director Ricardo Mota Palomino warned that summer peak demand could surpass the previous record of 53,000 MW, potentially reaching around 54,000 MW. Meeting these peaks requires ensuring sufficient generation and reserves to cover unexpected consumption increases or system failures. Combined cycle power plants are vital, contributing 61% of Mexico's electricity, according to the Mexican Institute for Competitiveness (IMCO).

The system's reliance on these plants becomes particularly evident as solar generation declines. While photovoltaic output diminishes to zero after sunset, demand remains high due to cooling equipment. The National Transmission Network Expansion and Modernization Program (PAMRNT) analyzes this challenge, especially for the Northwest and North regions. Scenarios for summer 2024 show solar generation peaking at midday and then disappearing, forcing CENACE to verify sufficient reserves, transmission capacity, and operational flexibility to meet evening demand.

Recent diagnoses from CENACE indicate that some electrical corridors operated near their limits due to various factors. These included generation unavailability caused by natural gas supply issues, technical failures, and delays in transmission projects and new power plants. The system's resilience depends on maintaining a balance between generation sources and transmission infrastructure, especially during periods of high demand and fluctuating renewable energy output.

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We are expecting it to reach around 54,000 megawatts approximately. We have been expecting that number for a year, but distributed generation takes away apparent growth because we do not measure that energy directly.