Technoeconomics of large-scale clean hydrogen production – A review

Hydrogen is widely used in many industries, yet its role in the clean energy transition goes beyond being an element of these industries. Near-term practical large-scale clean hydrogen production can be made available by involving nuclear, solar, and other renewable energy sources in the process of hydrogen production, and coupling their energy systems to sustainable carbon-free hydrogen technologies. This requires further investigation and assessment of the different alternatives to achieve clean hydrogen using these pathways. This paper assesses the technoeconomics of promising hydrogen technologies that can be coupled to nuclear and solar energy systems for large-scale hydrogen production. It also provides an overview of the design, status and advances of these technologies.     

Conceptual design of a Ca–Cu chemical looping process for hydrogen production in integrated steelworks

A novel configuration of the Ca–Cu looping process is proposed for the production of a H₂-enriched fuel gas by means of the sorption enhanced water gas shift (SEWGS) of blast furnace gas (BFG) in steel mills. CO₂ is simultaneously removed from the gas using a CaO-based sorbent. A Cu/CuO chemical loop supplies the energy required for the regeneration of the sorbent via the exothermic reduction of CuO with coke oven gas (GOG). The process is carried out in an arrangement of interconnected fluidized-bed reactors operating at atmospheric pressure, which allows for a solids' segregation step to be introduced that will reduce significantly the solid circulation between reactors A reference case study is presented, where the SEWGS is operated at 600 °C and the regeneration of the sorbent at 870 °C. About 27% of the BFG can be decarbonized in the SEWGS reactor producing 110 Nm³ of H₂ per tonne of steel. A CO₂ capture ratio of 31% with respect to the total carbon emissions in the steel mill can be achieved. More than 60% of the thermal input can be recovered as high-temperature heat, which could be efficiently recovered for producing electricity.     

Kinetics of mixed copper–iron based oxygen carriers for hydrogen production by chemical looping water splitting

Water splitting for hydrogen production through chemical looping was investigated in a micro fluidized bed reactor. Iron, copper and mixed iron–copper based oxygen carriers were prepared by coprecipitation and incipient wetness impregnation and compared in terms of H₂ production via decomposition of water. The powders were completely reduced in hydrogen (10%), and exposed to steam at temperature ranging from 500 to 800 °C producing about 0.2 mmol of H₂ per gram of metal oxide in the case of a mixed Cu–Fe powder. Powders prepared by coprecipitation showed poor fluidization properties as well as poor reactivity compared to those synthesized through impregnation. Temperature Programmed Reductions (TPR) experiments carried out on a TGA showed that particles have different oxygen carrying capacities, ranging from 16% in the case of a copper oxide prepared by coprecipitation, to around 1% for other particles prepared impregnation. Kinetics were evaluated following gas–solid mechanisms for two mixed Fe–Cu carriers. Oxidation of the mixed Fe–Cu carrier prepared by impregnation is well represented by a shrinking core model (phase-boundary-controlled). The activation energy for oxidation of this carrier was 46 kJ/mol. Oxidation of the mixed Fe–Cu carrier prepared by coprecipitation is well represented by a nuclei growth model (Avrami) with random nucleation and an activation energy of 51 kJ/mol.     

Biodiesel resources and production technologies – A review

The environmental concern and availability of fuels are greatly affecting the trends of fuels for transportation vehicles. Biodiesel is one of the options as alternative transport fuel. This can be produced from straight vegetable oils (SVOs), oils extracted from various plant species and animal fats. Amongst many resources, availability and cost economy are the major factors affecting the large scale production of the biodiesels. The transesterification is one of the production processes for biodiesel, but incomplete esterification of all fatty acids in the starting material, lengthy purification methods such as water washing, relatively long reaction times, contamination and separation difficulties associated with co-production of glycerol and saponification of the starting material under certain reaction conditions are still being major challenges in the biodiesel production. Technological advancement and enhanced production methods are the demand of present time for large scale and sustainable production of biodiesel. In the present paper, comprehensive review on its production process, feed stock and its applications have been made. From many case studies it was concluded that engine performance with B20 biodiesel blends, and mineral diesel were found comparable.     

Application of a multicriteria methodology for evaluation of energy alternatives for hydrogen production for the automotive sector – Case study

This paper presents a case study focusing on fourteen most used energy alternatives in Brazil, possible to feed large scale hydrogen production plants for the automotive sector. The evaluations are made using a Decision Making Support Method, MACBETH - Measuring Attractiveness by a Categorical Based Evaluation Technique, with the computational code M-MACBETH 3.2.0, using criteria that include economic and financial, technological, environmental and social aspects. The selected criteria that were used in the assessment, for each of the energy alternatives are capital to be invested in a plant, leveled cost of electric energy produced, CO₂ emissions, mortality rate due to the technology use and energy efficiency of technology. The main results obtained showed that photovoltaics off grid electric energy is the most attractive alternative, followed by the photovoltaic on grid alternative, for an eventual automotive hydrogen program in Brazil.     

A flexible techno-economic analysis tool for regional hydrogen hubs – A case study for Ireland

The increasing urgency with which climate change must be addressed has led to an unprecedented level of interest in hydrogen as a clean energy carrier. Much of the analysis of hydrogen until this point has focused predominantly on hydrogen production. This paper aims to address this by developing a flexible techno-economic analysis (TEA) tool that can be used to evaluate the potential of future scenarios where hydrogen is produced, stored, and distributed within a region. The tool takes a full year of hourly data for renewables availability and dispatch down (the sum of curtailment and constraint), wholesale electricity market prices, and hydrogen demand, as well as other user-defined inputs, and sizes electrolyser capacity in order to minimise cost. The model is applied to a number of case studies on the island of Ireland, which includes Ireland and Northern Ireland. For the scenarios analysed, the overall LCOH ranges from €2.75–3.95/kgH₂. Higher costs for scenarios without access to geological storage indicate the importance of cost-effective storage to allow flexible hydrogen production to reduce electricity costs whilst consistently meeting a set demand.     

An intelligent oxygen carrier of La2−xSrxNiO4−λ for hydrogen production by chemical looping reforming of ethanol

This work studied an intelligent perovskite of La_2?xSr_xNiO_4?λ as oxygen carrier (OC) to produce hydrogen in chemical looping reforming (CLR) process. It was prepared by co-precipitation method and investigated by XRD, TEM, ICP-OES, H₂-TPR, TGA technologies and fixed-bed experiment. The ‘intelligence’ refers to the self-regeneration ability and structural flexibility of perovskite. The former was verified by the movement that Ni ions repeatedly immerse into and out of perovskite bulk during CLR process. The movement suppressed the growth of Ni particles and maintained its high dispersion. The latter was confirmed by the addition of promoters. The insertion of Sr increased lattice oxygen mobility and greatly strengthened the reversible evolution of metallic Ni, which boosted the carbon-resistance and hold favorable stability of OC. The La_1.4Sr_0.6NiO_4?λ was the optimized composition owing to the superior activity, higher hydrogen selectivity (87%) and admirable stability. Moreover, shortened ‘dead time’ and more ideal self-regeneration property of perovskite were attained due to easier reducibility of Ni ions.     

Transient safety evaluation of the heat pipe microreactor – Potential energy source for hydrogen production

Recently, microreactor designs have been receiving significant attention in the nuclear industry due to their potential advantages in certain applications. These nuclear reactor designs have been considered to provide reliable and sustainable power for on-site installation and operation. Microreactors may be utilized to provide heat and power to hydrogen production, remote communities, and industrial facilities such as military installations, disaster relief zones, and are being considered for underwater and deep space operation as well. However, these designs and concepts remain largely untested and unproven in the commercial industry. Further research and development are still required to prove microreactor designs are safe and reliable for commercial use. Different cooling technologies have been taken into consideration for microreactor concepts since the 1960s, mainly for federal space reactor projects such as LEGOLRCS, HOMER, and KRUSTY. This work provides thermal hydraulics and analysis for the Idaho National Laboratory's MAGNET (Micro-reactor Agile Non-nuclear Experimental Testbed) facility. The MAGNET facility is currently being developed to duplicate a microreactor design using heat pipe cooling technology. Our main goal is to examine the response of the test facility under steady-state and transient operation conditions. We constructed our own estimated model of the MAGNET geometry using a software coupling method made up of MOOSE/SAM software systems. The steady state results of this work have been published in a former article. The new results mainly focus on the transient states. By communicating with the Idaho National Laboratories, we upgraded the geometry of MAGNET heat pipes. This not only verifies the design of the facility under such conditions but also benchmarks the modeling capability of the MOOSE/SAM code system that can be potentially used to model other microreactor concepts in the future.     

Continuous hydrogen production via the steam–iron reaction by chemical looping in a circulating fluidized-bed reactor

The steam–iron reaction was examined in a two-compartment fluidized-bed reactor at 800–900 °C and atmospheric pressure. In the fuel reactor compartment, freeze-granulated oxygen carrier particles consisting of Fe₃O₄ supported on inert MgAl₂O₄ were reduced to FeO with carbon monoxide or synthesis gas. The reduced particles were transferred to a steam reactor compartment, where they were oxidized back to Fe₃O₄ by steam, while at the same time producing H₂. The process was operated continuously and the particles were transferred between the reactor compartments in a cyclic manner. In total, 12 h of experiments were conducted of which 9 h involved H₂ generation. The reactivity of the oxygen carrier particles with carbon monoxide and synthesis gas was high, providing gas concentrations reasonably close to thermodynamic equilibrium, especially at lower fuel flows. The amount of H₂ produced in the steam reactor was found to correspond well with the amount of fuel oxidized in the fuel reactor, which suggests that all FeO that was formed were also re-oxidized. Despite reduction of the oxygen carrier to FeO, defluidization or stops in the solid circulation were not experienced. Used oxygen carrier particles exhibited decreased BET specific surface area, increased bulk density and decreased particle size compared to fresh. This indicates that the particles were subject to densification during operation, likely due to thermal sintering. However, stable operation, low attrition and absence of defluidization were still achieved, which suggest that the overall behaviour of the oxygen carrier particles were satisfactory.     

Environmental impact categories of hydrogen and ammonia driven transoceanic maritime vehicles: A comparative evaluation

In this study, carbon-free fuels -ammonia and hydrogen-are proposed to replace heavy fuel oils in the engines of maritime transportation vehicles. Also, it is proposed to use hydrogen and ammonia as dual fuels to quantify the reduction potential of greenhouse gas emissions. An environmental impact assessment of transoceanic tanker and transoceanic freight ship is implemented to explore the impacts of fuel substituting on the environment. In the life cycle analyses, the complete transport life cycle is taken into account from manufacture of transoceanic freight ship and tanker to production, transportation and utilization of hydrogen and ammonia in the maritime vehicles. Several hydrogen and ammonia production routes ranging from municipal waste to geothermal options are considered to comparatively evaluate environmentally benign methods. Besides global warming potential, environmental impact categories of marine sediment ecotoxicity and marine aquatic ecotoxicity are also selected in order to examine the diverse effects on marine environment. Being carbon-neutral fuels, ammonia and hydrogen, yield significantly minor global warming impacts during operation. The ecotoxicity impacts on maritime environment vary based on the production route of hydrogen and ammonia. The results imply that even hydrogen and ammonia are utilized as dual fuels in the engines, the global warming potential is quite lower in comparison with heavy fuel oil driven transoceanic tankers. Geothermal energy sourced hydrogen and ammonia fuelled transoceanic tankers release about 0.98 g and 1.65 g CO₂ eq. per tonne-kilometer, respectively whereas current conventional heavy fuel oil tanker releases about 5.33 g/tonne-kilometer CO₂ eq. greenhouse gas emissions.     

A review on wind energy and wind–hydrogen production in Turkey: A case study of hydrogen production via electrolysis system supplied by wind energy conversion system in Central Anatolian Turkey

Studies about investigation of hydrogen production from wind energy and hydrogen production costs for a specific region were reviewed in this study and it was shown that these studies were rare in the world, especially in Turkey. Therefore, the costs of hydrogen, hydrogen production quantities using a wind energy conversion system were considered as a case study for 5 different locations of Nigde, Kirsehir, Develi, Sinop and Pinarbasi located in the Central Anatolia in Turkey. Annual wind energy productions and costs for different wind energy conversion systems were calculated for 50 m, 80 m and 100 m hub heights. According to wind energy costs calculations, the amounts and costs of hydrogen production were computed. Furthermore, three different scenarios were taken into account to produce much hydrogen. The results showed that the hydrogen production using a wind energy conversion system with 1300 kW rated power had a range from 1665.24 kgH₂/year in Nigde at 50 m hub height to 6288.59 kgH₂/year in Pinarbasi at 100 m hub height. Consequently, Pinarbasi and Sinop have remarkable wind potential and potential of hydrogen production using a wind–electrolyzer energy system.     

The value chain of green hydrogen for fuel cell buses – A case study for the Rhine-Main area in Germany

As an immanent necessity to reduce global greenhouse gas emissions, the energy transition poses a major challenge for the next 30 years, as it includes a cross-sectoral increase of fluctuating renewable energy production, grid extension to meet regional electricity supply and demand as well as an increase of energy storage capacity. Within the power-to-gas concept, hydrogen is considered as one of the most promising solutions.The paper presents a scenario-based bottom-up approach to analyse the hydrogen supply chain to substitute diesel with fuel cell buses in the Rhine-Main area in central Germany for the year 2025. The analysis is based on field data derived from the 6 MW power-to-gas plant “Energiepark Mainz” and the bus demonstration project “H₂-Bus Rhein-Main”. The system is modelled to run simulations on varying demand scenarios. The outcome is minimised hydrogen production costs derived from the optimal scheduling of a power-to-gas plant in terms of the demand. The assessment includes the energy procurement for hydrogen production, different hydrogen delivery options and spatial analysis of potential power-to-gas locations.     

Effects of economies of scale and experience on the costs of energy-efficient technologies – case study of electric motors in Germany

Increasing energy efficiency is discussed as an effective way to protect the climate, even though this is frequently associated with additional (investment) costs when compared to standard technologies. However, the investment costs of emerging energy-efficient technologies can be reduced by economies of scale and experience curve effects. This also brings about higher market penetration by lowering market barriers. Experience curves have already been analyzed in detail for renewable energy technologies, but are not as well documented for energy-efficient technologies despite their significance for energy and climate policy decisions. This work provides empirical evidence for effects of economies of scale and experience on the costs of energy-efficient electric motors. We apply a new methodology to the estimation of learning effects that is particularly promising for energy-efficient technologies where the very low data availability did not allow calculations of learning rates so far. Energy-efficient electric motors are a highly relevant energy technology that is responsible for about 55% of German electricity consumption. The analysis consists of three main steps. First, the calculation of composite price indices based on gross value added statistics for Germany which show the changes in cost components of electric motors over the period 1995 to 2006; second, an estimation of the corresponding learning rate which is, in a third step, compared with learning rates observed for other energy-efficient technologies in a literature review. Due to restrictions of data availability, it was not possible to calculate a learning rate for the differential costs of energy-efficient motors compared to standard motors. Still, we estimated a learning rate of 9% for “Eff2” motors in a period when they penetrated the market and replaced the less efficient “Eff3” motors. Furthermore, we showed the contribution of different effects to these cost reductions, like a reduction of material use per motor produced by 15% and an improvement of labor productivity of 43%.     

Comparative study of large-scale hydrogen storage technologies: Is hydrate-based storage at advantage over existing technologies?

Different technologies possibly applicable for large-scale hydrogen storage in urban or industrial-complex areas have been comparatively evaluated, focusing on the facility-construction costs, the utility expense, and the ground area required for the facility for each technology. The specific technologies examined in this study are the storage in the form of compressed or liquefied gas, the storage using a metal hydride, and the storage using a clathrate hydrate. The common requirements for these technologies are the function of loading or unloading hydrogen gas at a rate up to 3000 Nm³/h and also the storage capacity of 6.48 × 10⁶ Nm³ that enables continuous 90-day loading or unloading at the rate of 3000 Nm³/h. The storage using a clathrate hydrate is found to require the minimum ground area and, if the cool energy necessary for hydrate production is available from adjacent LNG facilities, the minimum annual depreciation + utility expense.     

A solution to renewable hydrogen economy for fuel cell buses – A case study for Zhangjiakou in North China

Fuel cell vehicles fueled with renewable hydrogen is recognized as a life-cycle carbon-free option for the transport sector, however, the profitability of the H₂ pathway becomes a key issue for the FCV commercialization. By analyzing the actual data from the Zhangjiakou fuel cell transit bus project, this research reveals it is economically feasible to commercialize FCV in areas with abundant renewable resources. Low electricity for water electrolysis, localization of H₂ supply, and curtailed end price of H₂ refueling effectively reduce the hydrogen production, delivery and refueling cost, and render a chance for the profitability of refueling stations. After the fulfillment of the intense deployment of both vehicles and hydrogen stations for the 2022 Winter Olympics, the H₂ pathway starts to make a profit thereafter. The practices in the Zhangjiakou FCB project offer a solution to the hydrogen economy, which helps to break the chicken-egg dilemma of vehicles and hydrogen infrastructure.     

Pricing and affordability of renewable energy in China – A case study of Shandong Province

The global warming and climate change have put enormous pressure on both governments and industries to re-think their attitudes and behaviours towards sustainability issues. The past decades have witnessed a number of renewable energy developments across the world. Even though these developments are not issue-free, it is generally recognized that the benefits outweigh disadvantages. However, there is an increasing level of concern on the high initial cost associated with the renewable energies, which was claimed as one of critical barriers to the promotion of its further developments. A case study approach is adopted in this study to investigate the pricing and affordability issues associated with the renewable energy in China. The policy framework and related statistics are critically reviewed in order to discuss these issues from different stakeholders’ perspective in Shandong province, China. It is concluded that the affordability remains a critical issue despite numerous efforts have been made by the Chinese Government and Shandong Provincial Government on renewable power pricing. This study offers a useful reference to pricing and affordability of renewable energy.     

A systematic literature review of societal acceptance and stakeholders’ perception of hydrogen technologies

This paper presents the results of a systematic review that analysed the literature on factors influencing societal acceptance and stakeholders’ perceptions of hydrogen related technologies. This study found that the most influencing factors include prior knowledge, perceived cost/risks, environmental knowledge, higher education and income, personal and distributive benefits, infrastructure availability and close proximity to hydrogen facilities. There was low hydrogen awareness in more than 60% of the countries analysed in the reviewed studies. Although stakeholders had diverse perceptions, there was agreement that infrastructure availability, affordability, local community engagement, regional skill capability development, preservation of biodiversity, and safety and distributive benefits to the community were essential for a successful hydrogen industry. Future research could examine consumer acceptance at different geographical scales, analyse pre-and post-hydrogen project implementation, and social impact of hydrogen infrastructure on local communities. We also recommend diversifying hydrogen research projects and investigating the policy and regulatory arrangements for community-owned hydrogen projects.     

Impacts of nano-metal oxides on hydrogen production in anaerobic digestion of palm oil mill effluent – A novel approach

In the present study, hydrogen production from palm oil mill effluent (POME) was investigated with the incorporation of nanoparticles (NPs) comprising of nickel (NiO) and cobalt oxides (CoO). The NPs of NiO and CoO were prepared using hydrothermal method and were further applied to analyse, their effect on hydrogen production. The results demonstrated that, a maxima volumetric hydrogen production rate of 21 ml H₂/L-POME/h with the hydrogen yield of 0.563 L H₂/g-COD_removed was obtained with 1.5 mg/L concentration of NiO NPs. On the other hand, the addition of CoO NPs produced maximum volumetric hydrogen production rate of 18 ml H₂/L-POME/h with a hydrogen yield of 0.487 L H₂/g-COD_removed with 1.0 mg/L of CoO NPs. Results showed that addition of optimal concentration of NiO and CoO NPs to the POME enhances the hydrogen yield by 1.51 and 1.67 fold respectively. Besides, this addition of NiO and CoO enhanced the COD removal efficiency by 15 and 10% respectively as compared to an un-additive NPs POME. The toxicity of NPs was also tested using bacterial viability test, which revealed that application of 3.0 mg/L of NiO and CoO NPs to modified Luria-Bertani (LB) medium had 63% and 83% reduction in bacterial cell growth. The results concluded that supplementation of NiO and CoO NPs under an optimal range to the wastewater can improve the hydrogen productivity.     

Techno-economical evaluation of a hydrogen refuelling station powered by Wind-PV hybrid power system: A case study for İzmir-Çeşme

Hydrogen fuelling station is an infrastructure for the commercialisation of hydrogen energy utilising fuel cells, particularly, in the automotive sector. Hydrogen fuel produced by renewable sources such as the solar and wind energy can be an alternative fuel to depress the use of fuels based on fossil sources in the transport sector for sustainable clean energy strategy in future. By replacing the primary fuel with hydrogen fuel produced using renewable sources in road transport sector, environmental benefits can be achieved. In the present study, techno-economic analysis of hydrogen refuelling station powered by wind-photovoltaics (PV) hybrid power system to be installed in ?zmir-Çe?me, Turkey is performed. This analysis is carried out to a design of hydrogen refuelling station which is refuelling 25 fuel cell electric vehicles on a daily basis using hybrid optimisation model for electric renewable (HOMER) software. In this study, National Aeronautics and Space Administration (NASA) surface meteorology and solar energy database were used. Therefore, the average wind speed during the year was assessed to be 5.72 m/s and the annual average solar irradiation was used to be 5.08 kW h/m²/day for the considered site. According to optimisation results obtained for the proposed configuration, the levelised cost of hydrogen production was found to be US $7.526–7.866/kg in different system configurations. These results show that hydrogen refuelling station powered by renewable energy is economically appropriate for the considered site. It is expected that this study is the pre-feasibility study and obtained results encougare the hydrogen refuelling station to be established in Turkey by inventors or public institutions.     

A synthetical evaluation of developing low-carbonized coal-fired power technologies in China

This study is attempted to analyze the integrated effects of low-carbonized developments for Chinese coal-fired power industry in two cases by extending a hybrid energy-economic model. The first case is energy efficiency improvement without CCS introduction. The second case is direct carbon removal with CCS technology, while coal controlling policy scenario is set as a baseline for comparison. Here oxy-fuel combustion has been selected as the only carbon capture technology due to its great potential in commercialization. Then the ecological co-benefits, environmental benefits, macroeconomic impacts and water saving effects of CO₂ abatement from Chinese coal-fired power industry are analyzed. Simulation results show that energy saving and coal controlling policy can create huge ecological, environmental and water saving benefits. However, coal controlling policy also will cause great macroeconomic losses. But due to extra energy consumption, the large-scale commercialization of oxy-fuel CCS technology if without CO₂ reuse will cause certain decrease of GDP growth rate and increase water consumption in China. Only when combined with resource usage of the captured CO₂, oxy-fuel CCS introduction in China can have some practical application value.