How much energy does a single ChatGPT prompt actually use?
Got curious about this at a hackathon a few weeks ago and went down a rabbit hole.
Turns out a single AI prompt uses somewhere between 0.3 and 3 Wh of energy. Complex reasoning prompts can hit 33 Wh. For context, AI data centers are projected to produce around 80 million tons of CO₂ this year alone.
The other thing we noticed is that most prompts are way longer than they need to be. People write 200 words when 40 would get the same result. That's wasted tokens, wasted compute, wasted energy.
We ended up building a small tool that estimates the environmental cost of a prompt and rewrites it shorter. Mostly just to visualize the problem. It ended up winning Most Innovative at NY Tech Week which was cool but now we're genuinely trying to figure out: does anyone here actually think about this stuff? Or is the per-prompt cost so small that it doesn't matter to you?
Here's the demo if anyone wants to mess with it: https://terrawatch-ai.vercel.app/