Ranked by light delivered per unit of energy. Note these options serve different roles - mains or battery lighting for everyday use versus a human-powered lamp as an emergency fallback - so the comparison shows output, not interchangeability. Class-level theoretical ranges, as everywhere in this catalogue.
Solutions
LED lighting: Low-power artificial lighting; can run on either AC or DC bus.
Gravity-powered lamp: A slowly descending weight drives a small generator through a gear train, powering an LED for roughly 20-30 minutes per lift (a few seconds of lifting effort) a