The Hydrogen Science Coalition's five guiding principles are: (1) only green hydrogen (made via electrolysis with renewable electricity) counts as near-zero emission; (2) hydrogen should be used only where it's a chemical, not a fuel (ammonia, steel, petrochemicals); (3) electrification must not be delayed by hydrogen hype; (4) blending hydrogen into gas grids is wasteful and yields only 6% emissions reduction vs. better efficiency gains; (5) hydrogen must be produced locally, not transported.