Improving hydrogen refueling stations to achieve minimum refueling costs for small bus fleets

Fuel cell vehicles using green hydrogen as fuel can contribute to the mitigation of climate change. The increasing utilization of those vehicles creates the need for cost efficient hydrogen refueling stations. This study investigates how to build the most cost efficient refueling stations to fuel small fleet sizes of 2, 4, 8, 16 and 32 fuel cell busses. A detailed physical model of a hydrogen refueling station was built to determine the necessary hydrogen storage size as well as energy demand for compression and precooling of hydrogen. These results are used to determine the refueling costs for different station configurations that vary the number of storage banks, their volume and compressor capacity.It was found that increasing the number of storage banks will decrease the necessary total station storage volume as well as energy demand for compression and precooling. However, the benefit of adding storage banks decreases with each additional bank. Hence the cost for piping and instrumentation to add banks starts to outweigh the benefits when too many banks are used. Investigating the influence of the compressor mass flow found that when fueling fleets of 2 or 4 busses the lowest cost can be reached by using a compressor with the minimal mass flow necessary to refill all storage banks within 24 h. For fleets of 8, 16 and 32 busses, using the compressor with the maximum investigated mass flow of 54 kg/h leads to the lowest costs.     

Characterization of the electrical energy consumption of a building for the dimensioning of a solar‐hydrogen energy system

The photovoltaic (PV) applications where the dimensioning is effected through the daily energy balance criteria obtained by the estimation of the energy consumption depending on the power and time of use of the electrical apparatus are limited to autonomous PV systems with well‐defined end use. Applications where one would like to electrify complex end use, such as office buildings, schools, hospitals, laboratories, residential units, etc., quantifying the daily energy consumption is difficult mainly due to two aspects. First, there will be great number of a variety of electrical appliances and second the proportionate electrical consumption of each one of them is unpredictable. For this reason it is necessary to establish a methodology that permits one to quantify precisely the daily energy consumption pattern to predict the energetic functioning of the PV system whose size may be determined by this procedure. In this work we describe a methodology for the energetic quantification of the installed equipments by using a Power Quality Analyzer to obtain the historical global energy consumption, daily energy consumption (kWh day⁻¹, kVAh day⁻¹) and the energy quality for the dimensioning of the PV system. Copyright © 2009 John Wiley & Sons, Ltd.     

Estimating global production and supply costs for green hydrogen and hydrogen-based green energy commodities

Green energy commodities are expected to be central in decarbonising the global energy system. Such green energy commodities could be hydrogen or other hydrogen-based energy commodities produced from renewable energy sources (RES) such as solar or wind energy. We quantify the production cost and potentials of hydrogen and hydrogen-based energy commodities ammonia, methane, methanol, gasoline, diesel and kerosene in 113 countries. Moreover, we evaluate total supply costs to Germany, considering both pipeline-based and maritime transport. We determine production costs by optimising the investment and operation of commodity production from dedicated RES based on country-level RES potentials and country-specific weighted average costs of capital. Analysing the geographic distribution of production and supply costs, we find that production costs dominate the supply cost composition for liquid or easily liquefiable commodities, while transport costs dominate for gaseous commodities. In the case of Germany, importing green ammonia could be more cost-efficient than domestic production from locally produced or imported hydrogen. Green ammonia could be supplied to Germany from many regions worldwide at below the cost of domestic production, with costs ranging from 624 to 874 $/t NH₃ and Norway being the cheapest supplier. Ammonia production using imported hydrogen from Spain could be cost-effective if a pan-European hydrogen pipeline grid based on repurposed natural gas pipelines exists.     

Techno-economic evaluation of two hydrogen supply options to southern Germany: On-site production and import from Portugal

Hydrogen production through electrolysis using renewable electricity is considered a major pathway and component for a sustainable energy system of the future. For this production pathway, a high renewable energy potential, especially in solar energy, is crucial. Countries like Germany with a high energy demand and low solar potential strongly depend on hydrogen import. In the present work, a case study with two alternative hydrogen supply options is conducted to evaluate the economic viability of solar hydrogen delivered to a hydrogen pipeline in Stuttgart, Germany. For both options, hydrogen is generated through an 8 MW alkaline electrolyser, solar powered and supported by grid-based electricity to meet the required load. The first option is based on a hydrogen production system that is positioned in Sines, Portugal, an area with high global radiation and proximity to a deep sea port. The hydrogen is processed by liquefaction and transported to Stuttgart by tanker ship via Hamburg and by truck. The second supply option uses an on-site hydrogen production system in Stuttgart.The work shows that the production costs in Sines with 2.09 €/kgH₂ (prices in €₂₀₂₁) are, as expected, significantly lower than in Stuttgart with 3.24 €/kgH₂. However, this price difference of 1.15 €/kgH₂ for hydrogen production drops to a marginal difference of 0.13 €/kgH₂ when considering the whole value chain to the delivery point in Stuttgart. If the waste heat from electrolysis is used in a district heating system in Stuttgart, the price difference is down to 0.03 €/kgH₂. The first supply option is dominated by costs for processing, especially liquefaction. These costs would need to be reduced to fully exploit the cost advantage of solar hydrogen production in Portugal. Also, a fundamental switch to pipeline transport of gaseous hydrogen should be considered. Both investigated hydrogen supply options show the potential to provide the pipeline in Stuttgart with hydrogen at lower costs than by using the alternative technology of steam reforming of natural gas.     

Techno-economic analysis of hydropower based green ammonia plant for urea production in Nepal

This study presents a detailed design, economic, sensitivity and uncertainty analysis for establishing a hydropower based green ammonia plant for use in urea manufacturing in the context of Nepal. The electrolyzer plant for producing hydrogen was simulated with the help of DWSIM while the air separation and ammonia synthesis units were simulated with the help of Aspen Plus for producing 1245 ton/day of ammonia to meet the annual urea demand of Nepal. The capitalized cost of the electrolyzer, air separation and the ammonia synthesis unit of this size were calculated to be 26 million, 7 million and 9 million USD/year respectively. The levelized cost of hydrogen (H₂) and ammonia (NH₃) were found to be 3602 and 826 USD/ton respectively. Economic profitability analysis showed profitability of the plant with ROI and IRR of 38% and 26% respectively with a payback period of three years after operation. The sensitivity analysis showed strong sensitivity on the utility (electricity) cost for both the electrolyzer and ammonia synthesis unit which presents a strong opportunity for Nepal. The levelized cost for H₂ and NH₃ varied between 2845 USD/ton and 4361 USD/ton and 634 USD/ton and 1018 USD/ton respectively for ±30% variation in the utility (electricity) cost. Uncertainty analysis using Monte Carlo method showed the possible minimum levelized cost of H₂ and NH₃ to be 2340 USD/ton and 418 USD/ton respectively. This study illustrates the potential of hydropower based ammonia synthesis for urea manufacturing and provides an important baseline value for policymakers to make investment decisions and to formulate policies for this pathway of production.     

Techno-economic calculations of small-scale hydrogen supply systems for zero emission transport in Norway

In Norway, where nearly 100% of the power is hydroelectric, it is natural to consider water electrolysis as the main production method of hydrogen for zero-emission transport. In a startup market with low demand for hydrogen, one may find that small-scale WE-based hydrogen production is more cost-efficient than large-scale production because of the potential to reach a high number of operating hours at rated capacity and high overall system utilization rate. Two case studies addressing the levelized costs of hydrogen in local supply systems have been evaluated in the present work: (1) Hydrogen production at a small-scale hydroelectric power plant (with and without on-site refueling) and (2) Small hydrogen refueling station for trucks (with and without on-site hydrogen production). The techno-economic calculations of the two case studies show that the levelized hydrogen refueling cost at the small-scale hydroelectric power plant (with a local station) will be 141 NOK/kg, while a fleet of 5 fuel cell trucks will be able to refuel hydrogen at a cost of 58 NOK/kg at a station with on-site production or 71 NOK/kg at a station based on delivered hydrogen. The study shows that there is a relatively good business case for local water electrolysis and supply of hydrogen to captive fleets of trucks in Norway, particularly if the size of the fleet is sufficiently large to justify the installation of a relatively large water electrolyzer system (economies of scale). The ideal concept would be a large fleet of heavy-duty vehicles (with a high total hydrogen demand) and a refueling station with nearly 100% utilization of the installed hydrogen production capacity.     

Assessing sizing optimality of OFF-GRID AC-linked solar PV-PEM systems for hydrogen production

Herein, a novel methodology to perform optimal sizing of AC-linked solar PV-PEM systems is proposed. The novelty of this work is the proposition of the solar plant to electrolyzer capacity ratio (AC/AC ratio) as optimization variable. The impact of this AC/AC ratio on the Levelized Cost of Hydrogen (LCOH) and the deviation of the solar DC/AC ratio when optimized specifically for hydrogen production are quantified. Case studies covering a Global Horizontal Irradiation (GHI) range of 1400–2600 kWh/m²-year are assessed. The obtained LCOHs range between 5.9 and 11.3 USD/kgH₂ depending on sizing and location. The AC/AC ratio is found to strongly affect cost, production and LCOH optimality while the optimal solar DC/AC ratio varies up to 54% when optimized to minimize the cost of hydrogen instead of the cost of energy only. Larger oversizing is required for low GHI locations; however, H₂ production is more sensitive to sizing ratios for high GHI locations.     

Comparative performance analysis of a grid connected PV system for hydrogen production using PEM water,methanol and hybrid sulfur electrolysis

This paper presents comparative performance analysis of photovoltaic (PV) hydrogen production using water, methanol and hybrid sulfur (SO₂) electrolysis processes. Proton exchange membrane (PEM) electrolysers are powered by grid connected PV system. In this system design, electrical grid is considered as a virtual energy storage system (VESS) where the surplus of PV production can be injected and subsequently taken to support the electrolyser. Methanol (ME) and hybrid sulfur (HSE) electrolysis are compared to the conventional water electrolysis (WE) in term of operating cell voltage. Based on the experimental results reported in the literature, semi-empirical models describing the relationship between the hydrogen production rate and the electrolyser cell power input are proposed. Furthermore, power and hydrogen management strategy (PHMS) is developed. Case study is carried out to show the impact of each type of electrolysis on the system component sizes and evaluate the hydrogen production potentialities. Results show that the use of ME allows to produce 65% more hydrogen than with using WE. Moreover, the amount of hydrogen produced is almost double in the case of HSE. At Algiers city, based on a grid connected PV/Electrolyser system, it is possible to produce about 25 g/m² d and 29 g/m² d of hydrogen, respectively, through ME and HSE compared to 15 g/m² d of hydrogen when using WE.     

Low-emission hydrogen production via the thermo-catalytic decomposition of methane for the decarbonisation of iron ore mines in Western Australia

The Pilbara, located in Western Australia is one of the largest iron ore-mining regions in the world and will need to achieve significant emission reductions in the short term to conserve the limited carbon budget and abide by the Paris Agreement targets. Green hydrogen has been communicated as the desired solution, however, the high production cost limits the deployment of these systems. The thermo-catalytic methane decomposition (TCMD) process is an alternative solution, which could be implemented as a bridge technology to produce low-emission hydrogen at a potentially lower cost. This is especially attractive for iron ore mines due to the utilisation of iron ore as a process catalyst, which reduces the catalyst turnover costs and can increase the grade of spent iron ore catalyst. In this study, a preliminary techno-economic assessment was carried out in comparison with green hydrogen to determine the feasibility of the TCMD process for the decarbonisation of iron ore mine sites in the Pilbara. The results show that the TCMD process had a CO₂ abatement cost between 25 and 40% less than green hydrogen, however, the magnitude of these costs was lowest for mining operations >60 Mt/yr at approximately $150 and $200 USD/t CO₂ respectively. Since green hydrogen is expected to have significant cost reductions in the future, integrating renewables already into the mine could reduce emissions in the short term, which could then be extended for green hydrogen production once it becomes viable. The TCMD process, therefore, only has a narrow window of opportunity, although considering the uncertainty of the process and that green hydrogen is a proven technology with greater emission-reduction potential, green hydrogen may be the most suitable solution despite the model results presented in this work.     

Techno-economic optimization of PV system for hydrogen production and electric vehicle charging stations under five different climatic conditions in India

India is one of the most populous countries in the world, and this has implications for its energy consumption. The country's electricity generation and road transport are mostly dominated by fossil fuels. As such, this study assessed the techno-economics and environmental impact of a solar photovoltaic power plant for both electricity and hydrogen production at five different locations in India (i.e., Chennai, Indore, Kolkata, Ludhiana, and Mumbai). The hydrogen load represents a refueling station for 20 hydrogen fuel cell vehicles with a tank capacity of 5 kg for each location. According to the results, the highest hydrogen production occurred at Kolkata with 82,054 kg/year, followed by Chennai with 79,030 kg/year. Ludhiana, Indore, and Mumbai followed with 78,524 kg/year, 76,935 kg/year and 74,510 kg/year, respectively. The levelized cost of energy (LCOE) for all locations ranges between 0.41 and 0.48 $/kWh. Mumbai recorded the least LCOH of 3.00 $/kg. The total electricity that could be generated from all five cities combined was found to be about 25 GWh per annum, which translates to an avoidable emission of 20,744.07 metric tons of CO₂e. Replacing the gasoline that could be used to fuel the vehicles with hydrogen will result in a CO₂ reduction potential of 2452.969 tons per annum in India. The findings indicate that the various optimized configurations at the various locations could be economically viable to be developed.     

Green hydrogen production potential for developing a hydrogen economy in Pakistan

Pakistan's energy crisis can be diminished through the use of Renewable and alternative sources of energy. Hydrogen as an energy vector is likely to replace the fossil fuels in the future owing to the political, financial and environmental factors associated with the latter. In this regard it is imperative that conscious effort is directed towards the production of hydrogen from Renewable resources. Renewable energy resources are abundantly available in Pakistan. The need to produce Hydrogen from Renewable resources in Pakistan (or any developing economy) is investigated because it is possible to store vast amount of intermittent renewable energy for later use. Thus the introduction of Hydrogen in the energy supply chain implies the start of a Pakistan Hydrogen Economy. Many nations have developed the Hydrogen Energy Roadmap, and if Pakistan has to follow suite it is only possible through the employment of Renewable energy resources. This study estimates the potential of different Renewable resources available in Pakistan i.e. Solar, Wind, Geothermal, Biomass and Municipal Solid waste. An estimate is then made for the potential of producing hydrogen from various established technologies from each of these Renewable resources. A number of reviews have been published stating the availability and usage of Renewable energy in Pakistan; however no specific study has been focused on the use of Renewable resources for developing a Hydrogen economy or a power-to-gas system in Pakistan. This study concludes that that Biomass is the most feasible feedstock for developing a Hydrogen supply chain in Pakistan with a potential to generate 6.6 million tons of Hydrogen annually, followed by Solar PV that has a generation potential of 2.8 million tons and then Municipal solid waste with a capacity of 1 million ton per annum.     

Design concepts of hydrogen supply chain to bring consumers offshore green hydrogen

This study presents design concepts for hydrogen supply chains as a way to investigate how to transport green hydrogen from offshore sites to onshore sites where it would be available to consumers. The six concepts suggested are based on compressed hydrogen, a pipeline, liquefied hydrogen, liquid organic hydrogen carriers (LOHC), ammonia, and a subsea cable. Most of the concepts transported the hydrogen from production to consumption sites, but in the case of the subsea cable transferred electricity from the offshore wind farm. All the design concept were created to satisfy the same specific case study. For this case study, the East Sea was selected as the hydrogen production site, Busan port was chosen as the hydrogen consumption site. The six concepts were applied to the suggested case study before being compared from the viewpoint of each system's complexity. The results show that the pipeline- and subsea cable-based hydrogen supply chains are relatively simple relative to the other concepts, the LOHC- and ammonia-based hydrogen supply chains are inherently more complex because they require de-hydrogenation and cracking processes to extract hydrogen from the LOHC and ammonia. On the other hand, ammonia and liquefied hydrogen have advantages in terms of ship transportation because they both provide high volumetric densities. In the case of ammonia, the infrastructure required would be significantly reduced if it could be directly used as a fuel without the cracking and purification processes. This study proposes and compares various hydrogen supply chain concepts with the goal that the results will prove helpful to those attempting to create an offshore hydrogen supply chain by providing fundamental data to decision-makers in the early design stages.     

Exploring the feasibility of green hydrogen production using excess energy from a country-scale 100% solar-wind renewable energy system

When planning large-scale 100% renewable energy systems (RES) for the year 2050, the system capacity is usually oversized for better supply-demand matching of electrical energy since solar and wind resources are highly intermittent. This causes excessive excess energy that is typically dissipated, curtailed, or sold directly. The public literature shows a lack of studies on the feasibility of using this excess for country-scale co-generation. This study presents the first investigation of utilizing this excess to generate green hydrogen gas. The concept is demonstrated for Jordan using three solar photovoltaic (PV), wind, and hybrid PV-wind RESs, all equipped with Lithium-Ion battery energy storage systems (ESSs), for hydrogen production using a polymer electrolyte membrane (PEM) system. The results show that the PV-based system has the highest demand-supply fraction (>99%). However, the wind-based system is more favorable economically, with installed RES, ESS, and PEM capacities of only 23.88 GW, 2542 GWh, and 20.66 GW. It also shows the highest hydrogen annual production rate (172.1 × 10³ tons) and the lowest hydrogen cost (1.082 USD/kg). The three systems were a better option than selling excess energy directly, where they ensure annual incomes up to 2.68 billion USD while having payback periods of as low as 1.78 years. Furthermore, the hydrogen cost does not exceed 2.03 USD/kg, which is significantly lower than the expected cost of hydrogen (3 USD/kg) produced using energy from fossil fuel-based systems in 2050.     

PV system design for powering an industrial unit for hydrogen production

Needs for hydrogen, as a chemical feedstock, have been growing in the industry, more particularly in the petrochemical industry and in the floating glass technology. Moreover, by its versatility as an energy vector and its renewability, hydrogen has also become an attractive candidate as the vector energy of the future. This has resulted in large surge in demand for hydrogen. However, as hydrogen exists in nature mainly in combination with other elements, the development of its viable and sustainable production technologies has then become necessary.     

Heat management for hydrogen production by high temperature steam electrolysis

Many research and development projects throughout the world are devoted to sustainable hydrogen production processes. Low-temperature electrolysis, when consuming electricity produced without greenhouse gas emissions, is a sustainable process, though having limited efficiency.     

Hydrogen supply chain architecture for bottom-up energy systems models. Part 2: Techno-economic inputs for hydrogen production pathways

This article is the second paper of a serial study on hydrogen energy system modelling. In the first study, we proposed a stylized hydrogen supply chain architecture and its pathways for the representation of hydrogen systems in bottom-up energy system models. In this current paper, we aim to present and assess techno-economic inputs and bandwidths for a hydrogen production module in bottom-up energy system models. After briefly summarizing the current technological status for each production method, we introduce the parameters and associated input data that are required for the representation of hydrogen production technologies in energy system modelling activities. This input data is described both as numeric values and trend line modes that can be employed in large or small energy system models. Hydrogen production technologies should be complemented with hydrogen storage and delivery pathways to fully understand the system integration. In this context, we will propose techno-economic inputs and technological background information for hydrogen delivery pathways in later work, as the final paper of this serial study.     

CuAl layered double hydroxide as a highly efficient electrocatalyst for the electrolysis of water into hydrogen and oxygen fuels

The production of green H₂ through water electrolysis processes has become a prominent technology to deal with energy and environmental crisis worldwide. The total energy consumption of electrolysis processes can be reduced by the development of low-cost electrocatalysts. In this paper, we report first time the synthesis of a highly efficient 2D CuAl LDH electrocatalyst to produce the green H₂. The electrocatalyst was characterized with the help of various analytical instruments such as FT-IR, XRD, BET, TGA, ICP-OES, and XPS. The morphological characterization was done by SEM and TEM. The electrochemical characterization such as CV, LSV, Tafel plot, and EIS was done in acidic, basic, seawater, and alkaline seawater medium. It was found that CuAl LDH electrocatalyst exhibits a good current density of 100 mA/cm² at a potential of 1.178 V in acidic medium and 10 mA/cm² at 1.114V in seawater medium. It was investigated that the CuAl LDH behaves as a bifunctional electrocatalyst and exhibits excellent HER and OER activity in an acidic medium. The effect of temperature on the efficiency of the electrocatalyst under the above electrolyte mediums was also studied. The electrochemical data suggests that the CuAl LDH electrocatalyst can be utilized in an alkaline/PEM electrolyzer to produce the green H₂ at an industrial scale with optimum cost.     

Energy supply for water electrolysis systems using wind and solar energy to produce hydrogen: a case study of Iran

Due to acute problems caused by fossil fuels that threaten the environment, conducting research on other types of energy carriers that are clean and renewable is of great importance. Since in the past few years hydrogen has been introduced as the future fuel, the aim of this study is to evaluate wind and solar energy potentials in prone areas of Iran by the Weibull distribution function (WDF) and the Angstrom-Prescott (AP) equation for hydrogen production. To this end, the meteorological data of solar radiation and wind speed recorded at 10 m height in the time interval of 3 h in a five-year period have been used. The findings indicate that Manjil and Zahedan with yearly wind and solar energy densities of 6004 (kWh/m²) and 2247 (kWh/m²), respectively, have the greatest amount of energy among the other cities. After examining three different types of commercial wind turbines and photovoltaic (PV) systems, it becomes clear that by utilizing one set of Gamesa G47 turbine, 91 kg/d of hydrogen, which provides energy for 91 car/week, can be produced in Manjil and will save about 1347 L of gasoline in the week. Besides, by installing one thousand sets of X21-345 PV systems in Zahedan, 20 kg/d of hydrogen, enough for 20 cars per week, can be generated and 296 L of gasoline can be saved. Finally, the RETScreen software is used to calculate the annual CO₂ emission reduction after replacing gasoline with the produced hydrogen.     

Techno-economic assessment of green hydrogen and ammonia production from wind and solar energy in Iran

This paper presents a comprehensive technical and economic assessment of potential green hydrogen and ammonia production plants in different locations in Iran with strong wind and solar resources. The study was organized in five steps. First, regarding the wind density and solar PV potential data, three locations in Iran were chosen with the highest wind power, solar radiation, and a combination of both wind/solar energy. All these locations are inland spots, but since the produced ammonia is planned to be exported, it must be transported to the export harbor in the South of Iran. For comparison, a base case was also considered next to the export harbor with normal solar and wind potential, but no distance from the export harbor. In the second step, a similar large-scale hydrogen production facility with proton exchange membrane electrolyzers was modeled for all these locations using the HOMER Pro simulation platform. In the next step, the produced hydrogen and the nitrogen obtained from an air separation unit are supplied to a Haber-Bosch process to synthesize ammonia as a hydrogen carrier. Since water electrolysis requires a considerable amount of water with specific quality and because Iran suffers from water scarcity, this paper, unlike many similar research studies, addresses the challenges associated with the water supply system in the hydrogen production process. In this regard, in the fourth step of this study, it is assumed that seawater from the nearest sea is treated in a desalination plant and sent to the site locations. Finally, since this study intends to evaluate the possibility of green hydrogen export from Iran, a detailed piping model for the transportation of water, hydrogen, and ammonia from/to the production site and the export harbor is created in the last step, which considers the real routs using satellite images, and takes into account all pump/compression stations required to transport these media. This study provides a realistic cost of green hydrogen/ammonia production in Iran, which is ready to be exported, considering all related processes involved in the hydrogen supply chain.     

A robust optimization model for capacity configuration of PV/battery/hydrogen system considering multiple uncertainties

The capacity configuration optimization of photovoltaic (PV) hydrogen system with battery has been widely concerned, but many existing studies only take hydrogen as an energy storage mode of smooth power, rather than dedicated to hydrogen production to meet the needs of chemical plants for hydrogen, and it ignores the impact of the fluctuation of PV output and the uncertainty of hydrogen demand on the system capacity configuration optimization. For overcoming this disadvantage, a PV/battery/hydrogen system is proposed, which is specially used for hydrogen production, and for the sake of system economy, the excess power will be weighed whether to store it in the battery or sell it in the green certificate trading market, and a new trading model is formed. Moreover, a robust optimization model is established to deal with the impact of PV output, green power transaction price and hydrogen demand volatility on system capacity configuration. Finally, the characteristics of the model are tested by a real case of a chemical plant in Jiuquan City, Gansu Province. The results show that the capacity configuration scheme of the proposed model can effectively resist the demand uncertainty of hydrogen, the capacity of the electrolyzer and battery can still meet the needs of the chemical plant, even if the demand of the hydrogen increases by 40%.