Understand how we measure fusion success—and why Q=1 is just the beginning
Part of Build A Star: The Nuclear Fusion Revolution
Educational content slides
Q = Fusion Power Out / Heating Power In
This single number tells you if fusion is working:
Q < 1: Losing energy (not sustainable) Q = 1: Breakeven (historic milestone—first achieved Dec 2022!) Q = 10: ITER's target (proof commercial fusion is possible) Q = 20-30: Commercial power plant target
For comparison:
Test your understanding with this quiz.
If a reactor achieves Q=1 (breakeven), is it ready to power your home?
Complete this exercise and get AI-powered feedback.
It's 2035. You're an energy policy advisor. Fusion has achieved Q=15 consistently and commercial plants are 10 years away.
Think about: Energy mix strategy, risk management, systems thinking, and what unlimited clean energy would enable.
Key insight: Breakthrough technologies create second-order effects—solving one problem (energy) unlocks solutions to many others (water, climate, space).