Hydrogen production, storage, transportation and key challenges with applications: A review

Abstract

The energy demand worldwide has increased significantly with the increase in population. This is because energy is needed in almost every activity. For example, in industry, working, cleaning, transportation and commuting from one place to another. The majority of energy being used is obtained from fossil fuels, which are not renewable resources and require a longer time to recharge or return to its original capacity. Energy from fossil fuels is cheaper but it faces some challenges compared to renewable energy resources. Thus, one of the most potential candidates to fulfill the energy requirements are renewable resources and the most environmentally friendly fuel is hydrogen (H2). Hydrogen exists mostly in plant materials and is not readily available in nature. It is necessary to produce hydrogen from available feedstock (water), which covers 70% of the earth. Moreover, hydrogen under standard pressure and temperature has an important merit; it can be obtained from renewable resources. Although, currently it is produced from fossil fuels. Hydrogen as a fuel is nonmetallic, non-toxic and can generate higher energy than gasoline on a mass basis. However, to employ hydrogen as a fuel, extensive research is essential to investigate and design on-board applications. Also, the cost of producing hydrogen (renewable) is expensive compared to gasoline (fossil). Thus, the production of H2 from renewable resources and from fossil fuels requires tremendous effort. One of these efforts is to generate H2 from biofuels as it is considered a promising technique that can help manage hydrogen from food waste. In addition, hydrogen storage materials are still lacking in both volumetric and gravimetric density. In this review, the key challenges that hydrogen industry are confronting are introduced and highlighted to facilitate the use of hydrogen as an alternative energy. 1. Introduction With increasing global population, industrialization and urbanization, energy demand is rapidly rising [1]. Currently, about 85% of the overall energy consumption worldwide is obtained from non-renewable resources, namely, coal, natural gas and oil; contributes to environmental issues (global warming), economic issues and political crises. These resources are finite and its reserves worldwide are depleting which results in increasing price. The depletion of finite fossil fuels is a critical issue that needs to be overcome for a sustainable energy future. The exploration of new energy system arose during the oil crisis, in 1970, and the carbon dioxide level in the atmosphere increased which currently contributes to climate change. Moreover, development of new energy systems from renewable or sustainable resources is challenging [2]. Therefore