Hydrogen energy in changing environmental scenario: Indian context

This paper deals with how the Hydrogen Energy may play a crucial role in taking care of the environmental scenario/climate change. The R&D efforts, at the Hydrogen Energy Center, Banaras Hindu University have been described and discussed to elucidate that hydrogen is the best option for taking care of the environmental/climate changes. All three important ingredients for hydrogen economy, i.e., production, storage and application of hydrogen have been dealt with. As regards hydrogen production, solar routes consisting of photoelectrochemical electrolysis of water have been described and discussed. Nanostructured TiO₂ films used as photoanodes have been synthesized through hydrolysis of Ti[OCH(CH₃)₂]₄. Modular designs of TiO₂ photoelectrode-based PEC cells have been fabricated to get high hydrogen production rate (10.35 lh⁻¹ m⁻²). However, hydrogen storage is a key issue in the success and realization of hydrogen technology and economy. Metal hydrides are the promising candidates due to their safety advantage with high volume efficient storage capacity for on-board applications. As regards storage, we have discussed the storage of hydrogen in intermetallics as well as lightweight complex hydride systems. For intermetallic systems, we have dealt with material tailoring of LaNi₅ through Fe substitution. The La(Ni_l − xFe_x)₅ (x = 0.16) has been found to yield a high storage capacity of 2.40 wt%. We have also discussed how CNT admixing helps to improve the hydrogen desorption rate of NaAlH₄. CNT (8 mol%) admixed NaAlH₄ is found to be optimum for faster desorption (3.3 wt% H₂ within 2 h). From an applications point of view, we have focused on the use of hydrogen (stored in intermetallic La–Ni–Fe system) as fuel for Internal Combustion (IC) engine-based vehicular transport, particularly two and three-wheelers. It is shown that hydrogen used as a fuel is the most effective alternative fuel for circumventing climate change.     

Wind energy development and its environmental impact: A review

Wind energy, commonly recognized to be a clean and environmentally friendly renewable energy resource that can reduce our dependency on fossil fuels, has developed rapidly in recent years. Its mature technology and comparatively low cost make it promising as an important primary energy source in the future. However, there are potential environmental impacts due to the installation and operation of the wind turbines that cannot be ignored. This paper aims to provide an overview of world wind energy scenarios, the current status of wind turbine development, development trends of offshore wind farms, and the environmental and climatic impact of wind farms. The wake effect of wind turbines and modeling studies regarding this effect are also reviewed.     

Hydrogen production by hybrid system and its conversion by fuel cell in Algeria; Djanet

In this work we present a scenario of wind and solar energy production and seasonal energy storage producing Hydrogen in Djanet (East-South of Algeria). In addition we suppose assume the use of a set of fuel cells which are connected to the grid to provide a supply of energy when needed afterwards. The aim of this primary study is giving an alternative solution for the electric production in Djanet, which is mainly based on diesel generator. For that we made an investigation to highlight the potential of renewable energy production in this region. To ascertain feasibility of one hybrid system, we made energetic assessment considering the real climatic conditions of Djanet.     

Hydrogen electrolyser technologies and their modelling for sustainable energy production: A comprehensive review and suggestions

The advancement of hydrogen technology is driven by factors such as climate change, population growth, and the depletion of fossil fuels. Rather than focusing on the controversy surrounding the environmental friendliness of hydrogen production, the primary goal of the hydrogen economy is to introduce hydrogen as an energy carrier alongside electricity. Water electrolysis is currently gaining popularity because of the rising demand for environmentally friendly hydrogen production. Water electrolysis provides a sustainable, eco-friendly, and high-purity technique to produce hydrogen. Hydrogen and oxygen produced by water electrolysis can be used directly for fuel cells and industrial purposes. The review is urgently needed to provide a comprehensive analysis of the current state of water electrolysis technology and its modelling using renewable energy sources. While individual methods have been well documented, there has not been a thorough investigation of these technologies. With the rising demand for environmentally friendly hydrogen production, the review will provide insights into the challenges and issues with electrolysis techniques, capital cost, water consumption, rare material utilization, electrolysis efficiency, environmental impact, and storage and security implications. The objective is to identify current control methods for efficiency improvement that can reduce costs, ensure demand, increase lifetime, and improve performance in a low-carbon energy system that can contribute to the provision of power, heat, industry, transportation, and energy storage. Issues and challenges with electrolysis techniques, capital cost, water consumption, rare material utilization, electrolysis efficiency, environmental impact, and storage and security implications have been discussed and analysed. The primary objective is to explicitly outline the present state of electrolysis technology and to provide a critical analysis of the modelling research that had been published in recent literatures. The outcome that emerges is one of qualified promise: hydrogen is well-established in particular areas, such as forklifts, and broader applications are imminent. This evaluation will bring more research improvements and a road map to aid in the commercialization of the water electrolyser for hydrogen production. All the insights revealed in this study will hopefully result in enhanced efforts in the direction of the development of advanced hydrogen electrolyser technologies towards clean, sustainable, and green energy.     

Hydrogen station location optimization based on multiple data sources

A hydrogen station is one that fills or stores the hydrogen, which is critical to the commercial development of hydrogen energy and fuel cell vehicle industry. Therefore, its location planning becomes an important issue. Similar to the electric vehicle (EV) charging station's planning, several factors are considered including the location, the demand of the fuel, the driving distance, etc. In this paper, multiple data sources are applied to the site selection model, including the existing petrol-refueling station network data, geographic information system (GIS) data, population data and regional economic data. Based on the operation of the genetic algorithm, combined with the idea of the greedy algorithm and the annealing algorithm, we propose a multi-algorithm hybrid solution, which not only can avoid local optimal, but also can converge quickly. On the basis of the site selection scheme of the hydrogen station in California, we have optimized the location scheme in Beijing. Finally, we present the feasibility proposals for hydrogen station location in Beijing, including the appropriate number of hydrogen stations in different regions, the reasonable coverage distance of hydrogen stations, etc. Due to the huge development prospects for hydrogen energy and the urgent need to reduce the construction cost of hydrogen stations in China, this research can quickly optimize the location of the hydrogen station and further explore potential mathematical relationships, which has certain social significance and economic benefits.     

Towards The Hydrogen Economy: Estimation of green hydrogen production potential and the impact of its uses in Ecuador as a case study

The estimation of the green hydrogen (H₂) production potential represents the initial stage on the road to integrating the Hydrogen Economy into the energy systems of a country or region. This article has two purposes; the first focuses on identifying and analyzing studies on the amount of green H₂ obtainable in countries and regions across the globe. In total, 64 studies in 29 countries are reported, of which the geographical distribution of the estimates of green H₂ potential is obtained. Additionally, the most widely used renewable energy sources and the conversion technologies favored for their production were identified. The Americas and Argentina were the continents and the country, respectively, with the largest number of studies. At the same time, solar photovoltaic (PV) and electrolysis are the most studied production methods. The second purpose is to quantify the total potential of green H₂ in the Republic of Ecuador and explore its uses as an energy vector and chemical input in niches of opportunity detected from the analysis of its energy balance. In this regard, the total potential of green H₂ in Ecuador of 4.38 × 10⁸ tons/year is obtained, being the production of electrolytic H₂ with PV electricity the one with the highest contribution. The amount of H₂ available satisfies, in excess, the demand for the proposed uses: as fuel and chemical input. These results contribute to the knowledge of the object of study by making visible the interest of the countries in having such estimates and identifying the most attractive production route in the first place, and secondly, providing essential elements for the development of more detailed research and energy planning on the gradual incorporation of the Hydrogen Economy in Ecuador.     

Thermophilic fermentative hydrogen production from various carbon sources by anaerobic mixed cultures

In the present work, various carbon sources, xylose, glucose, galactose, sucrose, cellobiose, and starch were tested for thermophilic (60 °C) fermentative hydrogen production (FHP) by using the anaerobic mixed culture. An inoculum was obtained from a continuously-stirred tank reactor (CSTR) operated at pH 5.5 and HRT 12 h, and fed with tofu processing waste. The dominant species in the CSTR were found to be Thermoanaerobacterium thermosaccharolyticum and Clostridium thermosaccharolyticum, which are well known thermophilic H₂-producers in anaerobic-state, and have the ability to utilize a wide range of carbohydrates. When initial pH was adjusted to 6.8 ± 0.1 but not controlled during fermentation, vigorous pH drop began within 5 h, and finally reached 4.0–4.5 in all carbon sources. Although over 90% of substrate removal was achieved for all carbon sources except cellobiose (71.7%), the fermentation performances were profoundly different with each other. Glucose, galactose, and sucrose exhibited relatively higher H₂ yields whereas lower H₂ yields were observed for xylose, cellobiose, and starch. On the other hand, when pH was controlled (pH ≥ 5.5), the fermentation performance was enhanced in all carbon sources but to a different extent. A substantial increase in H₂ production was observed for cellobiose, a 1.9-fold increase of H₂ yield along with a substrate removal increase to 93.8%, but a negligible increase for xylose. H₂ production capabilities of all carbon sources tested were as follows: sucrose > galactose > glucose > cellobiose > starch > xylose. The maximum H₂ yield of 3.17 mol H₂/mol hexose_added achieved from sucrose is equivalent to a 26.5% conversion of energy content in sucrose to H₂. Acetic and butyric acids were the main liquid-state metabolites of all carbon sources while lactic acid was detected only in cellobiose, starch and xylose exhibiting relatively lower H₂ yields.     

Hydrogen production by methane decomposition: A review

Methane decomposition can be utilized to produce CO_X-free hydrogen for PEM fuel cells, oil refineries, ammonia and methanol production. Recent research has focused on enhancing the production of hydrogen by the direct thermocatalytic decomposition of methane to form elemental carbon and hydrogen as an attractive alternative to the conventional steam-reforming process. In this context, we review a comprehensive body of work focused on the development of metal or carbonaceous catalysts for enhanced methane conversion and on the improvement of long-term catalyst stability. This review also evaluates the roles played by various parameters, such as temperature and flow rate, on the rate of hydrogen production and the characteristics of the carbon produced. The heating source, type of reactor, operating conditions, catalyst type and its preparation, deactivation and regeneration and the formation and utilization of the carbon by-product are discussed and classified in this paper. While other hydrogen production methods, economic aspects and thermal methane decomposition methods using alternative heating sources such as solar and plasma are briefly presented in this work where relevant, the review focuses mainly on the thermocatalytic decomposition of methane using metal and carbonaceous catalysts.     

The production of hydrogen fuel from renewable sources and its role in grid operations

Understanding the scale and nature of hydrogen's potential role in the development of low carbon energy systems requires an examination of the operation of the whole energy system, including heat, power, industrial and transport sectors, on an hour-by-hour basis. The Future Energy Scenario Assessment (FESA) software model used for this study is unique in providing a holistic, high resolution, functional analysis, which incorporates variations in supply resulting from weather-dependent renewable energy generators. The outputs of this model, arising from any given user-definable scenario, are year round supply and demand profiles that can be used to assess the market size and operational regime of energy technologies. FESA was used in this case to assess what - if anything - might be the role for hydrogen in a low carbon economy future for the UK.In this study, three UK energy supply pathways were considered, all of which reduce greenhouse gas emissions by 80% by 2050, and substantially reduce reliance on oil and gas while maintaining a stable electricity grid and meeting the energy needs of a modern economy. All use more nuclear power and renewable energy of all kinds than today's system. The first of these scenarios relies on substantial amounts of ‘clean coal’ in combination with intermittent renewable energy sources by year the 2050. The second uses twice as much intermittent renewable energy as the first and virtually no coal. The third uses 2.5 times as much nuclear power as the first and virtually no coal.All scenarios clearly indicate that the use of hydrogen in the transport sector is important in reducing distributed carbon emissions that cannot easily be mitigated by Carbon Capture and Storage (CCS). In the first scenario, this hydrogen derives mainly from steam reformation of fossil fuels (principally coal), whereas in the second and third scenarios, hydrogen is made mainly by electrolysis using variable surpluses of low-carbon electricity. Hydrogen thereby fulfils a double facetted role of Demand Side Management (DSM) for the electricity grid and the provision of a ‘clean’ fuel, predominantly for the transport sector. When each of the scenarios was examined without the use of hydrogen as a transport fuel, substantially larger amounts of primary energy were required in the form of imported coal.The FESA model also indicates that the challenge of grid balancing is not a valid reason for limiting the amount of intermittent renewable energy generated. Engineering limitations, economic viability, local environmental considerations and conflicting uses of land and sea may limit the amount of renewable energy available, but there is no practical limit to the conversion of this energy into whatever is required, be it electricity, heat, motive power or chemical feedstocks.     

A well to pump life cycle environmental impact assessment of some hydrogen production routes

In the present study, a comparative well to pump life cycle assessment is conducted on the hydrogen production routes of water electrolysis, biomass gasification, coal gasification, steam methane reforming, hydrogen production from ethanol and methanol. The CML 2001 impact assessment methodology is employed for assessment and comparison. Comparatively higher life cycle Carbon dioxide and Sulphur oxide emissions of 27.3 kg/kg H₂ and 50.0 g/kg H₂ respectively are determined for the water electrolysis hydrogen production route via U.S. electricity mix. In addition, the life cycle global warming potential of this route (28.6 kg CO_2eq/kg H₂) is found to be comparatively higher than other routes followed by coal gasification (23.7 kg CO_2eq/kg H₂)_. However, the ethanol based hydrogen production route is estimated to have comparatively higher life cycle emissions of nitrogen dioxide (19.6 g/kg H₂) and volatile organic compounds (10.3 g/kg H₂). Moreover, this route is determined to have a comparatively higher photochemical ozone creation potential of 0.0045 kg-ethene_eq/kg H₂ as well as eutrophication potential of 0.0043 kg PO_4eq/kg H_2. The results of this study are comparatively discussed to signify the importance of life cycle assessment in comparing the environmental sustainability of hydrogen production routes.     

Hydrogen production in Mexico: State of the art,future perspectives,challenges, and opportunities

The use of hydrogen is increasing in many countries due to potential decarbonization and sustainable energy transition projects. Hydrogen is shown to be a versatile transition alternative in different applications, with an increasing trend towards clean alternatives with better performance improving the existing processes. This paper reviews (i) the international panorama of hydrogen production, (ii) the main alternatives for hydrogen production in Mexico, and (iii) the applications of hydrogen in various areas. The challenges and opportunities for the coming years to include and introduce the use of hydrogen in new and existing processes in Mexico are also analyzed. A great variety of alternatives to procedure hydrogen both in Mexico and on the international scenes are analyzed, contemplating different production mechanisms. Many of them are found to require further studies to make them profitable for industrial applications. Some challenges and opportunities are also analyzed, showing the importance of synchronizing the public-private partnership agenda on hydrogen production, and to provide the most favorable conditions for investment attraction and development. This review shows that Mexico has the opportunity to make a decisive incursion into hydrogen production.     

Hydrogen production by methane decarbonization: Carbonaceous catalysts

Decarbonization of natural gas by thermo-catalytic decomposition, TCD, to produce hydrogen and carbon is a very attractive alternative to steam methane reforming (SMR) for small-to-medium size facilities because by TCD, the carbon contained in natural gas is collected as a solid, marketable product. In this paper, the use of different carbon blacks with a high external surface area, easily accessible to methane molecules has been explored as an alternative to activated carbons.     

Hydrogen production using sono-biohydrogenator

Hydrogen production in a novel sonicated biological hydrogen reactor (SBHR) was investigated and compared with a continuous stirred tank reactor (CSTR). The two systems were operated at a hydraulic retention time (HRT) of 12 h and two organic loading rates (OLRs) of 21.4 and 32.1 g COD/L.d. The average hydrogen production rates per unit reactor volume for the conventional CSTR were 2.6 and 2.8 L/L.d, as compared with 4.8 and 5.6 L/L.d for SBHR, at the two OLRs, respectively. Hydrogen yields of 1.2 and 1.0 mol H₂/mol glucose were observed for the CSTR, respectively, while for the SBHR, the hydrogen yields were 2.1 and 1.9 mol H₂/mol glucose at the two OLRs, respectively. The hydrogen content in the SBHR’s headspace was higher than that in CSTR by 10% and 31% at OLRs of 21.4 and 32.1 g COD/L.d, respectively. Both glucose conversion efficiency and HAc/HBu ratio in the SBHR were higher than in the conventional CSTR at both OLRs. The biomass yield of about 0.32 g VSS/g COD observed in the CSTR and 0.23 g VSS/g COD in the SBHR substantiate the higher H₂ yield in the SBHR. DGGE analysis confirmed the specificity of the microbial hydrogen-producing culture in the SBHR, with two different hydrogen producers (Clostridium sp. and Citrobacter freundii) detected in the SBHR and not detected in the CSTR.     

Hydrogen production for energy: An overview

Power to hydrogen is a promising solution for storing variable Renewable Energy (RE) to achieve a 100% renewable and sustainable hydrogen economy. The hydrogen-based energy system (energy to hydrogen to energy) comprises four main stages; production, storage, safety and utilisation. The hydrogen-based energy system is presented as four corners (stages) of a square shaped integrated whole to demonstrate the interconnection and interdependency of these main stages. The hydrogen production pathway and specific technology selection are dependent on the type of energy and feedstock available as well as the end-use purity required. Hence, purification technologies are included in the production pathways for system integration, energy storage, utilisation or RE export. Hydrogen production pathways and associated technologies are reviewed in this paper for their interconnection and interdependence on the other corners of the hydrogen square.Despite hydrogen being zero-carbon-emission energy at the end-use point, it depends on the cleanness of the production pathway and the energy used to produce it. Thus, the guarantee of hydrogen origin is essential to consider hydrogen as clean energy. An innovative model is introduced as a hydrogen cleanness index coding for further investigation and development.     

Hydrogen production and End-Uses from combined heat,hydrogen and power system by using local resources

To address the problem of fossil fuel usage at the Missouri University of Science and Technology campus, using of alternative fuels and renewable energy sources can lower energy consumption and hydrogen use. Biogas, produced by anaerobic digestion of wastewater, organic waste, agricultural waste, industrial waste, and animal by-products is a potential source of renewable energy. In this work, we have discussed Hydrogen production and End-Uses from CHHP system for the campus using local resources. Following the resource assessment study, the team selects FuelCell Energy DFC1500™ unit as a molten carbonate fuel cell to study of combined heat, hydrogen and power (CHHP) system based on a molten carbonate fuel cell fed by biogas produced by anaerobic digestion. The CHHP system provides approximately 650 kg/day. The total hydrogen usage 123 kg/day on the university campus including personal transportation applications, backup power applications, portable power applications, and other mobility applications are 56, 16, 29, 17, and 5 respectively. The excess hydrogen could be sold to a gas retailer. In conclusion, the CHHP system will be able to reduce fossil fuel usage, greenhouse gas emissions and hydrogen generated is used to power different applications on the university campus.     

Hydrogen production using methane: Techno-economics of decarbonizing fuels and chemicals

In the near-to-medium future, hydrogen production will continue to rely on reforming of widely available and relatively low-cost fossil resources. A techno-economic framework is described that compares the current best practice steam methane reforming (SMR) with potential pathways for low-CO₂ hydrogen production; (i) Electrolysis coupled to sustainable renewable electricity sources; (ii) Reforming of hydrocarbons coupled with carbon capture and sequestration (CCS) and; (iii) Thermal dissociation of hydrocarbons into hydrogen and carbon (pyrolysis). For methane pyrolysis, a process based on a catalytic molten Ni-Bi alloy is described and used for comparative cost estimates. In the absence of a price on carbon, SMR has the lowest cost of hydrogen production. For low-CO₂ hydrogen production, methane pyrolysis is significantly more economical than electrochemical-based processes using commercial renewable power sources. At a carbon price exceeding $21 t^?1 CO₂ equivalent, pyrolysis may represent the most cost-effective means of producing low-CO₂ hydrogen and competes favorably to SMR with carbon capture and sequestration. The current cost disparity between renewable and fossil-based hydrogen production suggests that if hydrogen is to fulfil an expanding role in a low CO₂ future, then large-scale production of hydrogen from methane pyrolysis is the most cost-effective means during the transition period while infrastructure and end-use applications are deployed.     

Hydrogen production by low-temperature plasma decomposition of liquids

The paper shows, that a low-temperature plasma initiated in liquid media in interelectrode discharge gap is able to decompose hydrogen containing organic molecules resulting in obtaining gaseous products with volume part of hydrogen higher than 90% (up to gas chromatography data). Tentative assessments of energy efficiency, calculated with regard for hydrogen and feedstock heating value and energy consumption, have shown efficiency factor of 60–70%, depending on the source mixture composition. Theoretical model calculations of discharge current and voltage have been performed; the values are in good accordance with experimental data.     

Hydrogen production from polystyrene pyrolysis and gasification: Characteristics and kinetics

Polystyrene (PS) pyrolysis and gasification have been examined in a semi-batch reactor at temperatures of 700, 800 and 900 °C. Characteristic differences between pyrolysis and gasification of polystyrene (PS) have been evaluated with specific performance focus on the evolution of syngas flow rate, evolution of hydrogen flow rate, evolution of output power, syngas yield, hydrogen yield, energy yield, apparent thermal efficiency and syngas quality. Behavior of PS under either pyrolysis or gasification processes is compared to that of char based sample, such as paper and cardboard. In contrast to char based materials, PS gasification yielded less syngas, hydrogen and energy than pyrolysis at 700 °C. However, the gasification of PS yielded more syngas, hydrogen and energy than pyrolysis at 900 °C temperature. Gasification of PS is affected by reactor temperature more than PS pyrolysis. Syngas, hydrogen and energy yield increased exponentially with temperature in case of gasification. However, syngas and energy yield increased linearly with temperature having rather a mild slope in the case of pyrolysis. Pyrolysis resulted in higher syngas quality at all temperatures. Kinetics of hydrogen evolution from the PS pyrolysis is introduced. The Coats and Redfern method was used to determine the kinetic parameters, activation energy (E_act), pre-exponential factor (A) and reaction order (n). The model used is the nth order chemical reaction model. Kinetic parameters have been determined for three slow heating rates, namely 8, 10 and 12 °C/min. The average values obtained from the three heating rate experiments were used to compare the model with the experimental data.     

Hydrogen production and storage analysis of a system by using TRNSYS

In this study, hydrogen production and storage were investigated. The Transient System Simulation Program (TRNSYS) and Generic Optimization Program (GenOpt) packages were combined for the design and optimization of a system that produces hydrogen from water and stores the hydrogen it produced in the compressed gas tank. The system design is based on the electricity grid. Electrical energy produced in photovoltaic (PV) panels was used to electrolyze water. The systems for Izmir, Istanbul and Ankara provinces which are in different climate zones of Turkey were optimized and the annual system performances based on the optimum angles were analyzed. For the mentioned provinces, the PV tilt angles which minimize electricity drawn from the grid at the electrolyzer are also investigated. The electrical energy produced in the photovoltaic panels, the hydrogen and oxygen amounts produced, the efficiency of the electrolyzer, the gas and pressure levels in the hydrogen tank were compared. According to the results of the analysis, the annual total power produced in photovoltaic panels is 42803.66 kW in İzmir, 42573.74 kW in Istanbul and 44613.95 kW in Ankara. Hydrogen levels produced in the system are calculated as 10488.39 m³ year⁻¹ in Izmir, 9824.70 m³ year⁻¹ in Istanbul, and 10368.65 m³ year⁻¹ in Ankara.     

Review and comparison of various hydrogen production methods based on costs and life cycle impact assessment indicators

Hydrogen is a clean, renewable secondary energy source. The development of hydrogen energy is a common goal pursued by many countries to combat the current global warming trend. This paper provides an overview of various technologies for hydrogen production from renewable and non-renewable resources, including fossil fuel or biomass-based hydrogen production, microbial hydrogen production, electrolysis and thermolysis of water and thermochemical cycles. The current status of development, recent advances and challenges of different hydrogen production technologies are also reviewed. Finally, we compared different hydrogen production methods in terms of cost and life cycle environmental impact assessment. The current mainstream approach is to obtain hydrogen from natural gas and coal, although their environmental impact is significant. Electrolysis and thermochemical cycle methods coupled with new energy sources show considerable potential for development in terms of economics and environmental friendliness.