Future energy systems will be determined by the increasing relevance of renewable energy resources due to global warming, energy crisis, and pollution. Hydrogen is considered one of the promising alternative fuels to replace oil, but its storage remains a significant challenge. The main hydrogen storage technologies can be broadly classified as physical, chemical, and hybrid methods. The physical methods rely on compression and liquefaction of hydrogen, and currently, compressed hydrogen storage is the most mature technology that is commercially available. The chemical methods utilize materials to store hydrogen, and hydrogen can be extracted by on-board regenerable or off-board regenerable chemical reactions depending on the type of material. Hybrid methods take advantage of both physical and chemical storage methods. The most prominent hybrid method is the cryo-adsorption hydrogen storage which utilizes physisorption-based porous materials. The chapter describes these technologies and discusses alternative/novel hydrogen storage material technologies.
TopI. Introduction
Due to emerging Economies, global energy demand is increasing continuously. Relic fuels supply nearly 80% of energy demand worldwide; further, if reliance on Relic fuels is continued, the principal source of this energy may have foreseeable Imminent (Economics, 2018). Global Warming, Energy crisis and Pollution are the major problems facing by the current modern society due to the excessive utilization of Fossil Fuels. Finite production of fossil fuels possess Bell-shaped Curve with reference to the theory of Hubbert’s peak (Maggio & Cacciola, 2012; Houghton, 2005; Asif & Muneer 2007; Barbir et al.1990).
After Discovery of Certain reservoir for fossil fuel production it is leading to increase exponentially, then the rate of production decreases reaching peak point of depletion of fossil fuel and reduction in feasibility of extraction (Hubbert, 1956). So, it is understood that oil and other relic fuels, get exhausted in the near future. In the conveyance sector, oil is most important source of energy i.e., used excessively by mankind and according to the current estimates, the fuel that is likely to be depleted before end of twenty-first century is oil (Agrawal et al. 2007; Kerr, 2011).
A huge share in the world trade was contributed by oil economy, and any significant changes in it might take many years before it is completely comprehended; hence, it is domineering to act in present day towards finding cleaner replacements to oil. Even though the exhaustion of oil is vital concern which is required to be addressed at possible earliest, much more insistent issue requiring immediate attention is global warming. Increase in temperature of earth precisely due to anthropogenic emissions of CO2 which is caused by use of excessive fossil fuel is Global warming (Asif & Muneer 2007). Sea level rise and extreme weather are the impacts of global warming which in turn can cause worldwide environmental change and colossal community. Being time-sensitive problem an effective measure for prevention of irreversible changes in atmosphere needs to be designed and executed immediately (Yi,1996). Oil spills and air pollution caused by combustion are also a grave problems requiring attention. Particulates like NOx, COx (where X=1 or 2), SOz (where Z= 2 or 3) and benzene are emitted from mobile platforms are harmful to health. Densely populated areas are responsible for problematic air pollution. On the other hand, Aquatic life and Surrounding communities have long devastating effects due to large scale oil spills. Lastly, excessive utilization of fossil fuels threatens energy security. Oil reserves are usually present in unsteady areas of the world (Mendelssohn et al. 2012). The countries importing oil are facing the problems in meeting oil demands as a consequence of disrupted supply from the time to time. Due to this disruption failure in supply of oil, the countries will have grave economic, political and social impacts. Several countries have their individual natural reserves which are diminutive energy security and another long-term energy security policy to drive away from oil in near future (Asif & Muneer 2007).
From the preceding conversation, it is clearly evident that the alternative fuels are necessary to protect mother earth which also helps in reducing risks related with extreme oil use. Due to owing their unique property of high energy density, fuels derived from oil have extensively been used in transportable applications and becoming a formidable task to replace this oil (Asif & Muneer 2007).
Hydrogen is understood to be among the strongest contenders, that replaces the oil in transportable applications. Though hydrogen might not be an energy source similar to oil, it acts as an energy carrier, connotation hydrogen availability on earth is not direct, which requires its production through other sources. At present, a noteworthy share of hydrogen energy is produced from methane through the process of “steam methane reforming (SMR)”. Amongst other processes for the production of hydrogen is through water electrolysis; as this process uses production of electricity from renewable energy technologies since there is a possibility of hydrogen production from renewable energy sources.
After the production of hydrogen, transportation, distribution to end-user and storage for later use are some important stages that are needed to be addressed. The three stages of production, transportation and storage of hydrogen are called as hydrogen economy.