Hydrogen as a Clean and Sustainable Energy Vector for Global Transition from Fossil-Based to Zero-Carbon

Abstract

Hydrogen is recognized as a promising and attractive energy carrier to decarbonize the sectors responsible for global warming, such as electricity production, industry, and transportation. However, although hydrogen releases only water as a result of its reaction with oxygen through a fuel cell, the hydrogen production pathway is currently a challenging issue since hydrogen is produced mainly from thermochemical processes (natural gas reforming, coal gasification). On the other hand, hydrogen production through water electrolysis has attracted a lot of attention as a means to reduce greenhouse gas emissions by using low-carbon sources such as renewable energy (solar, wind, hydro) and nuclear energy. In this context, by providing an environmentally-friendly fuel instead of the currently-used fuels (unleaded petrol, gasoline, kerosene), hydrogen can be used in various applications such as transportation (aircraft, boat, vehicle, and train), energy storage, industry, medicine, and power-to-gas. This article aims to provide an overview of the main hydrogen applications (including present and future) while examining funding and barriers to building a prosperous future for the nation by addressing all the critical challenges met in all energy sectors.

A Comprehensive Survey of Alkaline Electrolyzer Modeling: Electrical Domain and Specific Electrolyte Conductivity

“…Energies 2022, 15, 3452 To highlight the strengths, weaknesses, opportunities, and threats of alkaline technology, a SWOT analysis has been carried out and reported in Table 1. Despite that alkaline technology features several advantages, it presents several weaknesses such as limited current density, frequent maintenance (liquid electrolyte), and limited production capacity dynamic range [6]. However, some opportunities might enhance the performance and hydrogen production of the technology by using new materials and designing stacks differently [23,24].…”

“…This makes hydrogen one of the cleanest fuels in the world and essential for achieving a pollution-free by 2050 according to the European Union's (EU) commitment. Unfortunately, its production is still largely dominated by fossil fuels (specifically natural gas) [4][5][6][7]. Only a small amount is produced through the water electrolysis process, which uses electricity to split water into hydrogen and oxygen.…”

“…To contribute to climate neutrality, hydrogen production must require electricity coming from RES or nuclear [8]. As hydrogen is applied in various energy-intensive sectors such as transport, industry, electricity, and buildings, it offers enormous solutions in the reduction of greenhouse gas emissions [6,9]. For clean and efficient power generation, fuel cells can be employed supplied by hydrogen and oxygen for which the reaction releases only heat and water.…”

Zirconia Toughened Alumina-Based Separator Membrane for Advanced Alkaline Water Electrolyzer

“…AWEs are in commercial use for quite a long time and are considered a mature technology [ 26 ]. However, they exhibit low operating pressure and limited partial load range, slow response time toward dynamic operations, and most importantly, low current densities (below 800 mA/cm 2 at 1.8 V), owing to the higher values of ionic resistance of the separator membrane and the lower kinetics caused by the utilization of non-noble type catalysts [ 27 , 28 , 29 ]. These lower densities increased the number of stacks required to obtain enough hydrogen [ 30 , 31 , 32 ].…”

Stability Tests on Anion Exchange Membrane Water Electrolyzer under On-Off Cycling with Continuous Solution Feeding

“…Several technologies are available for water electrolysis, including alkaline water electrolysis (AWE), proton exchange membrane water electrolysis (PEMWE), and anion exchange membrane water electrolysis (AEMWE). The first two are well commercialized, whereas the others are at the research level [11][12][13]. However, there is growing research interest in AEMWE owing to its potential to compete with PEMWE.…”