In May 2026, the United States experienced a historic shift in its electricity generation mix as solar power surpassed coal for the first time on record.According to analysis from the global energy think tank Ember, solar energy accounted for 12.8% of total U.S.electricity generation during the month, while coal contributed 12.2%.This marks a significant milestone in the ongoing transition toward cleaner energy sources in the country.The report highlights how quickly the energy landscape has changed.Just five years earlier, in May 2021, coal represented nearly 19.7% of U.S.electricity generation, while solar accounted for only 5.4%.In May 2026, solar generation reached a record 45.5 terawatt-hours, representing a 17% increase compared to May 2025 and surpassing previous production highs set the prior summer.

Analysts note that solar output typically peaks during early summer months due to stronger sunlight, although its share of the energy mix is often highest in spring when demand conditions are more favorable.The data also shows that coal generation continues its long-term decline, reaching an all-time monthly low of 39.3 TWh in April 2026 and only slightly rebounding to 43.4 TWh in May.Even with that modest increase, coal remained well below previous levels and was overtaken by rapidly expanding solar capacity.The report also notes that solar has now become the third-largest individual electricity source in the U.S., behind natural gas and nuclear power.

When combined with wind and other renewables, clean energy sources collectively represent an even larger share of the grid, underscoring a broader structural shift in the U.S.energy system toward lower-carbon electricity production.