Portugal expects solar power generation to fall by 45 percent during eclipse

Tuesday 11 August 2026 - 10:31

By: Azzat Manal

Portugal expects solar power generation to fall by 45 percent during eclipse

Portugal’s electricity system is preparing for a significant temporary drop in solar power generation as a solar eclipse is expected to affect the country’s electricity supply on August 12.

The national electricity network operator estimates that solar generation could decline by around 45 percent during the period affected by the eclipse, representing a loss of approximately 450 megawatts of available power.

According to the operator, the reduction could correspond to around 7 percent of national electricity consumption and approximately 45 percent of the solar generation expected under average system conditions at the time of the event.

The anticipated decline is linked to the temporary reduction in sunlight reaching solar panels as the Moon passes between the Earth and the Sun. Because solar generation has become an increasingly important component of electricity systems across Europe, sudden changes in sunlight can require grid operators to adjust other sources of power and maintain system stability.

Portuguese energy authorities are therefore coordinating with electricity transmission network operators in other European countries to prepare for the expected impact. The objective is to ensure that electricity supply remains balanced while solar production falls and subsequently recovers.

The eclipse is expected to occur during the afternoon of August 12 and is considered a particularly notable astronomical event for Portugal. The country has not experienced a total solar eclipse since 1912.

A total solar eclipse occurs when the Moon moves directly between the Earth and the Sun, temporarily blocking the Sun’s visible disk for observers located within the path of totality.

Beyond its astronomical significance, the event also provides an opportunity for energy operators to assess how increasingly solar-dependent electricity systems respond to rapid changes in renewable generation.

Portugal’s preparations highlight the growing need for flexible power systems as renewable energy accounts for a larger share of electricity production. Effective coordination between grid operators and the availability of alternative generation or other balancing resources can help manage short-term fluctuations in solar output.