Blue hydrogen combines fossil fuel-based grey hydrogen production regarding carbon capture & storage technology, capturing 85-95% of CO₂ emissions yet remaining approximately $2-4 per kilogram, approximately 100-200% more expensive than grey hydrogen. The energy penalty regarding carbon capture & storage, approximately 15-30% additional energy requirement, reduces blue hydrogen's overall efficiency substantially. Blue hydrogen represents transitional technology enabling emissions reduction while green hydrogen deployment scales, yet substantial technical, economic, & environmental challenges question whether blue hydrogen represents genuine climate solution or expensive band-aid perpetuating fossil fuel dependence while diverting investment from sustainable alternatives.