Hydrogen safety: The road toward green technology

With increasing world energy demands, the search for an environmentally-friendly fuel is a must. Hydrogen is a fuel that is energy-efficient and clean, and considered by many as the perfect fuel. The problem arises when it comes to safety considerations. It does not have a good reputation because of some unfortunate accidents during history. In this work the safety of hydrogen during production, transmission and use is reviewed. Hydrogen safety issues are mainly discussed in relation to its ignition and combustion characteristics namely: wide flammability range detonation level, low ignition energy, relatively high flame velocity, rapid diffusion and buoyancy, in addition to it its characteristics in the liquid phase. Hydrogen is the lightest gas (14 times lighter than air), highly flammable, odorless, and burns with a colorless flame. When used as a fuel, it supplies more energy per unit mass, than the popular fuels used today. In producing hydrogen, there are many processes, each one with its hazards, but these are relatively less weighed against hydrogen having the highest energy-carrying abilities. In storing, transmission and using of hydrogen, the main hazard is in its leaking, causing a fire to start. To detect when a leak happens, reliable and economic sensors should be used. High degree of safety, depending on hydrogen properties, is essential in any relevant design, to accelerate toward hydrogen economy. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.