Solar is adding around 600 TWh a year while coal has stopped growing, so even without any acceleration solar passes coal in the second half of the 2030s.
The indicator here is annual electricity generation by source, as reported each spring in Ember's Global Electricity Review. In 2025 solar rose by a record 636 TWh to 2,778 TWh [1]. Coal produced 10,476 TWh and, for the first time in a century, was overtaken by renewables taken together [2]. Solar on its own still has about 7,700 TWh to make up.
That gap is closing from both ends. The IEA expects solar output to rise by around 600 TWh in 2026 and by a similar amount in 2027 [3]. At that steady pace, with no acceleration at all, solar passes 10,000 TWh around 2038. Coal, meanwhile, has stopped growing in China, where it has been flat on a rolling 12-month basis since early 2024 [4]. A rolling figure adds up the latest twelve months each time it is updated, so one dry summer or one windy winter cannot disguise the direction. A steady walker overtakes someone standing still without ever needing to run.
The IEA's stated-policies scenario is quicker again, with coal the largest source of electricity only until the early 2030s [5].
basispoint's strongest point is that solar's growth rate is falling, and it is. But a lower rate on a much larger base can still add the same block of energy each year, and the IEA's figure of about 600 TWh was published this July, with China's slowdown already in view. A slower curve moves the year; it does not move it out of the century. My reading is the second half of the 2030s.
Ember's review of 2026, due next spring, will show whether the yearly increase held near 600 TWh. That one number will do more than any other to settle the decade.
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[1]
Global Electricity Review 2026
Solar power increased by a record 636 TWh to reach 2,778 TWh in 2025, a 30% increase from 2024.
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[2]
Global Electricity Review 2026: 2025 in review
For the first time in 100 years, renewables (33.8%, 10,730 TWh) overtook coal power (33.0%, 10,476 TWh).
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[3]
Electricity Mid-Year Update 2026: Executive summary
Output is forecast to increase by around 600 TWh in 2026, broadly matching the record annual expansion seen in 2025, with similar growth expected in 2027.
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[4]
China Energy Transition Review 2026
And 2025 is not an isolated result: coal generation has been flat on a rolling 12-month basis since early 2024, following years of continuous expansion.
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[5]
World Energy Outlook 2025
In the STEPS, global coal-fired power generation continues to expand in the near term, remaining the largest source of electricity until the early 2030s (Figure 4.22).
