https://futurism.com/the-byte/power-generate-single-ai-image
https://www.theregister.com/2023/12/04/ai_news_in_brief/
https://arxiv.org/pdf/2311.16863.pdf
Looks like the claim traces back to a paper which to be fair hasn't been peer reviewed as of Dec 2023. There's definitely a boatload of electricity in training but 3 minutes of searching didn't show anything conclusive about what's used in production.