Solar energy supplied 12.8% of US electricity in May 2026, surpassing coal’s 12.2% share for the first time in a full calendar month, according to analysis by global energy think tank Ember. The milestone marks a historic shift in the nation’s electricity mix, reflecting years of accelerating renewable capacity deployment and declining coal generation.
The May achievement was not an isolated event. Solar also exceeded coal in April 2026, generating 40.91 TWh compared with coal’s 39.78 TWh, making this the second consecutive month solar outpaced the fossil fuel. This sustained lead indicates the transition is deepening rather than fleeting, as solar generation reached 47.15 TWh in May, up 20.7% from May 2025, while coal-fired generation fell 7.5% over the same period.
The shift reflects coal’s long-term decline in the US power sector. Coal’s share of the electricity mix has nearly halved over five years, falling from 19.7% in May 2021 to 12.2% in May 2026, according to Ember. In the same period, solar’s share more than doubled, from 5.4% to 12.8%. Coal generation hit an all-time monthly low of 39.3 TWh in April 2026, underscoring the accelerating transition.
Solar is now the third-largest source of electricity in the United States, behind natural gas and nuclear power. Nicolas Fulghum, Senior Data Analyst at Ember, noted that this transformation reflects broader market dynamics: “US solar power continues to set new records. Overtaking coal for the first month on record shows just how far solar has come, from a niche contributor to the third-largest and fastest-growing source of power in the US electricity system. From Texas to California, markets across the US are betting on solar to meet rising power needs.”
The expansion is grounded in tangible capacity growth. Photovoltaic installations reached 222.69 GW by the end of May 2026, representing an 18.4% increase from 188.03 GW in May 2025. Large-scale photovoltaic plants accounted for 160.60 GW of this total, while small-scale installations (typically residential rooftop solar) contributed 62.09 GW. Generation from large-scale facilities rose 22.6% year-over-year, while small-scale solar generation climbed 15.3%.
This milestone builds on earlier clean energy progress. In March 2026, renewables collectively generated more electricity than natural gas for the first time in US history, according to Ember. That achievement demonstrated the speed at which the electricity mix is transforming, even as coal-fired capacity continues to decline and solar deployment accelerates across regions from the Southwest to Texas to California.
Sources
- Ember — May 2026 solar and coal generation shares, all-time monthly lows for coal, five-year trend analysis, and quote from Nicolas Fulghum on solar’s role in the US electricity system
- Energy & Climate Index — April and May 2026 solar and coal generation data (in TWh), year-over-year comparisons, and photovoltaic capacity figures as of May 2026
