Plant-powered usually means the main active ingredient in a product is plant-based. A common example of this would be using thyme oil as a disinfectant rather than chlorine bleach or other lab-made chemicals. On the other hand, plant-based products are mostly or entirely plant-derived, meaning that both the active AND inactive ingredients are derived directly from plant sources. That said, "plant-based" is not a highly regulated term, meaning that companies can label things as being plant-based even if their formulas aren't zero-chemical.