Nuclear fission and fusion generate more than 20% of global electricity in 2035.

Question

Six frontier AI models put this at 3% by 1 Oct 2036. Full reasoning from every model.

WillHappen.ai · Accepted Answer

3% — the median of 5 frontier models, resolving by 2036-10-01.

Answer

Gemini (Google): 2% — Nuclear share cannot more than double by 2035 because reactor construction lead times far exceed the available nine-year window. Global electricity demand will rise over 25% by 2035, requiring nuclear generation to nearly triple to hit a 20% total share. Conventional reactors take 7-10 years to build, meaning capacity commissioned by 2035 is essentially limited to projects already started. Commercial fusion and small modular reactors lack the deployed manufacturing pipelines needed to deliver hundreds of gigawatts this decade.

Answer

Claude (Anthropic): 2% — Nuclear share would need to more than double in 9 years, far beyond current construction pipelines. Global nuclear share has hovered near 9-10% for over a decade despite many extension and new-build announcements. Reactor construction lead times of 7-10+ years mean the 2035 fleet is already largely determined by projects now underway. Fusion contributes essentially 0% commercially and won't scale to grid relevance by 2035, so only fission counts realistically.

Answer

GPT (OpenAI): 7% — It turns on whether China, India and advanced economies sustain an unprecedented nuclear buildout for a decade. Nuclear supplied about 9% of global electricity in 2024; fusion is very unlikely to make material grid output by 2035. Exceeding 20% needs roughly a tripling of nuclear generation while global electricity demand also grows sharply through 2035. China can add reactors quickly, but OECD projects face financing, permitting and construction delays; a binding global build program would change this.

Answer

DeepSeek (DeepSeek): 5% — Doubling nuclear's share in nine years requires building at a pace no country has sustained since the 1980s. Global nuclear output is ~2,700 TWh; 20% of 2035 electricity (~35,000 TWh) needs ~7,000 TWh, a 2.6x jump in nine years. China adds ~2-3 GW/year and would need ~15-20 GW/year; the US, France, and Japan are extending lifetimes, not doubling capacity. Fusion contributes zero to the grid today and no commercial plant is expected before the 2040s, so it cannot close the gap.

Answer

Qwen (Alibaba): 3% — Doubling nuclear's share in 9 years requires construction rates never achieved outside wartime mobilization. Nuclear grew from ~9% to ~17% peak in the 1990s over 25 years; replicating that pace in half the time while fusion adds nothing commercial is implausible. Even optimistic IEA and IAEA scenarios project 12-15% by 2035; no credible forecast exceeds 16%, and current build pipelines (~60 GW under construction) can't close the… Fusion contributes zero commercial output by 2035—ITER won't reach net electricity, and no private fusion firm has a grid-connected plant planned before the 2030s.

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