Green hydrogen produced via renewable-powered water electrolysis is widely regarded as environmentally sustainable, yet existing life cycle assessments often differ in their treatment of upstream supply chain processes. This study evaluates four major electrolysis technologies-alkaline, proton exchange membrane, solid oxide electrolysis cell, and anion exchange membrane -using a harmonized cradle-to-gate framework that systematically incorporates all relevant upstream emission categories. Across all technologies, upstream supply chain emissions (scope 3) contribute 15-49% of total greenhouse gas burdens, underscoring their substantial influence on life cycle outcomes. Environmental performance is shaped by material requirements, operational efficiency, and component manufacturing intensity, with critical raw materials such as platinum, nickel, and high-temperature alloys emerging as major upstream drivers. Under a net-zero mitigation scenario in which conventional grid electricity is replaced with renewable electricity, total life cycle emissions decrease by 79-90% across all electrolysis technologies. Nevertheless, upstream supply chain processes remain significant contributors, indicating that electricity decarbonization alone is insufficient. Material efficiency, low-carbon manufacturing routes, durability improvements, and recycling strategies are essential to meaningfully reduce the carbon footprint of green hydrogen. Emerging technologies such as AEM demonstrate promising environmental potential owing to their balanced material profiles and reduced dependence on supply-constrained critical materials. This study provides a harmonized methodological foundation for evaluating the environmental performance of water electrolysis systems and highlights that achieving truly sustainable green hydrogen requires coordinated advances in supply chain decarbonization, technological efficiency, and renewable electricity integration.

Water scarcity presents a pressing global challenge, profoundly impacting both human societies and environmental ecosystems. Brackish water and seawater desalination serve as a crucial solution to alleviate water stress. While pressure-driven membrane processes - reverse osmosis (RO) and nanofiltration (NF) - dominate the desalination market, electrified desalination processes have experienced substantial development in recent years, attributed to their improved scalability and reduced fouling tendencies compared to the pressure-driven technologies. However, their energy efficiency compared to RO remains a subject of debate, as reflected by the conclusions of numerous recent studies that have performed such comparisons. To settle this debate and provide more direct conclusions regarding the use of electrified technologies for desalination, this study conducts a comprehensive survey of electrified desalination processes reported in the literature over the last decades, focusing on key desalination parameters such as feed salinity, salt removal, water recovery, and water productivity. Based on the literature survey, we identify membrane capacitive deionization (MCDI), electrodialysis (ED), and flow-electrode capacitive deionization (FCDI) as the most promising electrified technologies. Employing mechanistic process modeling, we rigorously compare the energy consumption of electrified technologies with RO. Furthermore, we integrate this modeling with techno-economic analysis to evaluate the economic viability of various desalination technologies. Results demonstrate promising prospects for electrified technologies, demonstrating lower energy consumption and comparable economics of ED and FCDI relative to RO in brackish water desalination. Using our framework, we explore the impacts of material advancements on performance enhancement, emphasizing the importance of reducing manufacturing material costs rather than solely focusing on fabricating high-performance materials. Overall, our study highlights the significance of integrated mechanistic modeling and techno-economic analysis in assessing and guiding the future of electrified desalination technologies. Importantly, these insights extend beyond desalination to the broader water-energy nexus, offering valuable implications for sustainable water resource management.

Industrial CO2 emission is a primary contributor to the global warming and as such an accelerator of the climate crisis. Countries worldwide have adopted the 'Paris Agreement' to restrict the global temperature rise below 2 degrees C, and ideally below 1.5 degrees C compared to the pre-industrial levels. Reactive absorption which utilizes aqueous alkanolamine solvents in an absorption and stripping column tandem is the current de-facto standard for a realistic, industrial-scale, post-combustion carbon capture. The solvent regeneration and high concentration CO2 release in the stripping column represents the bulk of the process's operating cost, due to high energy requirement of the reboiler unit ( 4-10 GJ / ton CO2). This fact alone makes the process prohibitively expensive in both energy and economic terms for many major CO2 emitting entities such as fossil fuel power plants, cement producers, refineries, etc. To address this issue in this work we present a new process topology concept entitled Clustered Carbon Capture. A cluster of major CO2 point sources in a variable radius all with CO2 absorption columns of appropriate scale share a centralized stripper column appropriately sized to regenerate the solvent for all the points in the cluster. As a proof-of-concept this work has 3 sources (300-2,000 MW coal power plants) and a 35 km radius. Utilizing the economies of scale on the most expensive and energy intensive unit our expected results should quantify the amount of cost reduction for the CO2 capture for each individual point of the cluster. Provided that the cost reduction is significant, clustered carbon capture might well represent an indispensable strategy for economic CO2 reduction on a large-scale, utilizing an already proven technology.

Lithium-ion batteries are becoming more ubiquitous, increasing lithium demand. Lithium carbonate, the most common form of industrial lithium, is primarily produced from lithium-rich brines concentrated using solar evaporation ponds. This extraction method is environmentally damaging and slow, taking a year or more to sufficiently concentrate. To meet the increasing demand, new technologies are being developed which can facilitate lithium recovery and shorten production timelines. This work examines two promising separations technologies, ion exchange resins due to their low cost and intercalation electrodes due to their high selectivity, and applies them to two potential alternative lithium sources - seawater reverse osmosis concentrate, and oil and gas produced water - to evaluate their efficacy. We develop process trains for each technology and analyze them using technoeconomic analysis and lifecycle assessment to determine economic and environmental feasibility. Further, technical improvements and process train modifications are examined to determine the impact on lithium carbonate cost. Our results show that currently ion exchange resins are the cheaper technology for recovering lithium, and that oil and gas produced water can produce lithium carbonate for as little as $14.96 kgLi(2)CO(3)(-1) while recovering 34.3 % of lithium in solution, making it economically viable as a recovery option. Given sufficient technical improvements, intercalation electrode production costs for lithium carbonate may also be competitive. The preferred technology for minimizing the environmental impact is dependent on water source, but the ion exchange resin paired with oil and gas produced water has the lowest environmental impact overall, producing only 17.7 kgCO(2)-eq kgLi(2)CO(3)(-1).

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Securing decarbonized economies for energy and commodities will require abundant and widely available green H2. Ubiquitous wastewaters and nontraditional water sources could potentially feed water electrolyzers to produce this green hydrogen without competing with drinking water sources. Herein, we show that the energy and costs of treating nontraditional water sources such as municipal wastewater, industrial and resource extraction wastewater, and seawater are negligible with respect to those for water electrolysis. We also illustrate that the potential hydrogen energy that could be mined from these sources is vast. Based on these findings, we evaluate the implications of small-scale, distributed water electrolysis using disperse nontraditional water sources. Techno-economic analysis and life cycle analysis reveal that the significant contribution of H2 transportation to costs and CO2 emissions results in an optimal levelized cost of hydrogen at small- to moderate-scale water electrolyzer size. The implications of utilizing nontraditional water sources and decentralized or stranded renewable energy for distributed water electrolysis are highlighted for several hydrogen energy storage and chemical feedstock applications. Finally, we discuss challenges and opportunities for mining H2 from nontraditional water sources to achieve resilient and sustainable economies for water and energy.

Modern technology relies on an undisrupted supply of metals, yet many metals have limited geological deposits. Recovering metals from wastewater and brine could augment metal stocks, but there is little guidance on which metals to prioritize for recovery or on the techno-economic viability of extraction processes. Here we critically assess the potential for recovering metals from wastewater and brine. We first look at which metals are critical for recovery on the basis of their supply risks and the impacts of those supply restrictions. We then assess the feasibility of recovering these metals from various water sources by estimating the required operational costs to match market prices. Next we discuss the limitations of established separation technologies that may inhibit the practicality and scalability of metal recovery from water. We conclude by highlighting materials and processes that could serve as more sustainable alternatives to metal recovery with further research and development. Recovering metals from wastewater and brine could augment metal stocks that are fundamental to modern technology. This Perspective assesses the potential of, and provides guidance for, recovering metals from wastewater and brine.

Recently, considerable attention has been paid to the installation of renewable energy capacity to mitigate global CO2 emissions. H2 produced using water electrolysis and renewable energy is regarded as a clean energy carrier, generating electricity without CO2 emissions, called ‘Green H2’. In this paper, a prognostics and health management model for an alkaline water electrolyzer was proposed to predict the load voltage on the electrolyzer to obtain the state of health information. The prognostics and health management model was developed by training historical operating data via machine learning models, support vector machine and gaussian process regression, showing the root mean square error of 1.28 × 10−3 and 8.03 × 10−6. In addition, a techno-economic analysis was performed for a green H2 production system, composed of 1 MW of photovoltaic plant and 1 MW of alkaline water electrolyzer, to provide economic insights and feasibility of the system. A levelized cost of H2 of $ 6.89 kgH2−1 was calculated and the potential to reach the levelized cost of H2 from steam methane reforming with carbon capture and storage was shown by considering the learning rate of the photovoltaic module and electrolyzer. Finally, the replacement of the alkaline water electrolyzer at around 10 years was preferred to increase the net present value from the green H2 production system when capital expenditure and replacement cost are low enough.

Early-stage evaluation of emerging technologies for water and energy through coupled process modeling and techno-economic analysis is key in assessing potential feasibility, providing the opportunity to target the most impactful technologies.

As the prices of photovoltaics and wind turbines continue to decrease, more renewable electricity-generating capacity is installed globally. While this is considered an integral part of a sustainable energy future by many nations, it also poses a significant strain on current electricity grids due to the inherent output variability of renewable electricity. This work addresses the challenge of renewable electricity surplus (RES) utilization with target-scaling of centralized power-to-gas (PtG) hydrogen production. Using the Republic of Korea as a case study, due to its ambitious plan of 2030 green hydrogen production capacity of 0.97 million tons year-1, we combine predictions of future, season-averaged RES with a detailed conceptual process simulation for green H2 production via polymer electrolyte membrane (PEM) electrolysis combined with a desalination plant in six distinct scale cases (0.5-8.5 GW). It is demonstrated that at scales of 0.5 to 1.75 GW the RES is optimally utilized, and PtG hydrogen can therefore outperform conventional hydrogen production both environmentally (650-2210 Mton CO2 not emitted per year) and economically (16-30% levelized cost reduction). Beyond these scales, the PtG benefits sharply drop, and thus it is answered how much of the planned green hydrogen target can realistically be "green" if produced domestically on an industrial scale.

While electrodialysis (ED) demonstrates lower energy consumption than reverse osmosis (RO) in the desalination of low salinity waters, RO continues to be the predominant technology for brackish water desalination. In this study, we probe this skewed market share and project the potential for future disruption by ED through systematic assessment of the levelized cost of water (LCOW). Using rigorous process- and economic-models, we minimize the LCOW of RO and ED systems, highlighting important tradeoffs between capital and operating expenditure for each technology. With optimized current state-of-the-art systems, we find that ED is more economical than RO for feed salinities ≤ 3 g L-1, albeit to a minor extent. Considering that RO is a highly mature technology, we focus on predicting the future potential of ED by evaluating plausible avenues for capital and operating cost reduction. Specifically, we find that reduction in the price of ion-exchange membranes (i.e., < 60 USD m-2) can ensure competitiveness with RO for feed salinities up to 5 g L-1. For higher feed salinities (≥ 5 g L-1) we reveal that the LCOW of ED may effectively be reduced by decreasing ion-exchange membrane resistance, while preserving high current efficiency. Through extensive assessment of structure-property-performance relationships, we precisely identify target membrane charge densities and diffusion coefficients which optimize the LCOW of ED, thus providing novel guidance for future membrane material development. Overall, we emphasize that with a unified approach - whereby ion-exchange membrane price is reduced and performance is enhanced - ED can become the economically preferable technology compared to RO across the entire brackish water salinity range.

A cobalt phthalocyanine having an electron-poor CoN4 (+δ) in its phthalocyanine moiety was presented as an electrocatalyst for hydrogen peroxide oxidation reaction (HPOR). We suggested that hydrogen peroxide as an electrolysis medium for hydrogen production and therefore as a hydrogen carrier, demonstrating that the electrocatalyst guaranteed high hydrogen production rate by hydrogen peroxide splitting. The electron deficiency of cobalt allows CoN4 to have the highly HPOR-active monovalent oxidation state and facilitates HPOR at small overpotentials range around the onset potential. The strong interaction between the electron-deficient cobalt and oxygen of peroxide adsorbates in Co─OOH- encourages an axially coordinated cobalt oxo complex (O═CoN4 ) to form, the O═CoN4 facilitating the HPOR efficiently at high overpotentials. Low-voltage oxygen evolution reaction guaranteeing low-voltage hydrogen production is successfully demonstrated in the presence of the metal-oxo complex having electron-deficient CoN4 . Hydrogen production by 391 mA cm-2 at 1 V and 870 mA cm-2 at 1.5 V is obtained. Also, the techno-economic benefit of hydrogen peroxide as a hydrogen carrier is evaluated by comparing hydrogen peroxide with other hydrogen carriers such as ammonia and liquid organic hydrogen carriers.

The well-established Haber-Bosch (HB) process (industrial ammonia production) is a significant contributor to the world's carbon emissions as it is a major consumer of natural gas as well as being energy-intensive in general. This work addresses the challenge of decarbonizing the HB process in a novel way as it, for the first time, presents a conceptual process integration with a supercritical CO2 Allam power cycle, therefore transforming gaseous CO2 emissions into a valuable side product in a form of liquid CO2. Detailed process design and flowsheet simulation using Aspen Plus (R) was used as a basis for scale-up and techno-economic assessment of two cases (electrical grid dependent and independent). The results indicated that using this process design NH3 production reaches profitability at scales larger than 2 ton h(-1) to 5.4 ton h(-1) and at current global NH3 prices, the cost of manufacturing decrease, due to scale-up stabilizes at similar to 30 ton h(-1). Finally, this novel process integration achieves a significant reduction in gaseous CO2 emissions (compared to conventional HB process) of 68 % to 96 %, which indicates great potential for economically feasible green NH3.

In this work, techno-economic and environmental assessments were conducted for green diesel production. In particular, two green diesel production pathways through thermochemical and electrochemical processes, which have different syngas production methods, were covered to evaluate the sustainability in terms of economic and environmental perspectives. The process modeling was performed for three cases, classifying cases according to the component composition, and verified by comparing the physical properties of conventional diesel and green diesel produced from syngas. From process modeling results, case 2 has the most relevant properties of conventional diesel showing the potential for alternative diesel fuel. With the process modeling results, cost estimation was carried out to calculate the current unit diesel production costs for three scenarios (according to the renewable energy sources); 0.0507, 0.0647, and 0.0547 $ MJ(-1) via the thermochemical process and 0.0477, 0.0606, and 0.0514 $ MJ(-1) through the electrochemical process for hydropower, solar PV, and onshore wind, respectively, showing the infeasibility due to the lower conventional ones (0.0164-0.0276$ MJ(-1)). To make the green diesel production attractive, uncertainty analysis and projected cost analysis were conducted to obtain the possible cost ranges due to the cost fluctuations of key economic parameters and the estimated unit diesel production cost in 2030, with the projected levelized cost of electricity by 2030 and learning rates by cumulative production of H2 and CO demands. Moreover, environmental assessment should be performed to identify whether the green diesel production is more eco-friendly or not than conventional one, by considering direct emission and indirect one emitted from energy consumption. From environmental assessment results, lower CO2 emissions can be investigated according to the renewable energy sources for green diesel production and the electrochemical green diesel production with onshore wind has the lowest CO2 emission among all scenarios covered in this work.

The economic viability of a methanol production process through carbon dioxide reforming of landfill gas using a newly developed nickel-based catalyst was assessed. The development of the catalyst and techno-economic analysis of the designed process were targeted. The nickel-based catalyst showed a highly active and stable performance even at an extremely high gas hourly space velocity of 1,620,000 mL g- 1h- 1. The high activity of the catalyst was due to the abundant nickel active sites (metallic nickel particles) on its surface. Coke formation was suppressed by the small particle size of nickel and relatively high oxygen storage capacity, resulting in a stable catalytic performance. In the process simulation, the methanol production system based on the nickelbased catalyst (new process) leveraged its smaller reformer size and more efficient heat utilization compared to those of a previously reported system based on a rhodium-based catalyst (base process) because of its higher gas hourly space velocity. The process simulation was conducted based on the gas hourly space velocity of 312,346 mL g- 1h- 1. The unit production costs of methanol were reduced from 184.0 $ ton- 1 in the base process to 117.5 $ ton-1 in the new process. In addition, profitability analysis based on the global market price of methanol demonstrated that the new process exhibited a positive net present value, indicating economic feasibility, whereas the base process was not viable in the worst-case scenario (lowest market price of methanol).

ADVERTISEMENT RETURN TO ISSUEPREVEnergy FocusNEXTPathways to a Green Ammonia FutureBoreum LeeBoreum LeeDepartment of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520-8286, United StatesMore by Boreum Lee, Lea R. WinterLea R. WinterDepartment of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520-8286, United StatesMore by Lea R. Winterhttps://orcid.org/0000-0002-6409-788X, Hyunjun LeeHyunjun LeeSchool of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of KoreaMore by Hyunjun Lee, Dongjun LimDongjun LimSchool of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of KoreaMore by Dongjun Lim, Hankwon Lim*Hankwon LimSchool of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea*Phone: +82 (52) 217-2935. Email: [email protected]More by Hankwon Limhttps://orcid.org/0000-0002-1074-0251, and Menachem Elimelech*Menachem ElimelechDepartment of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520-8286, United States*Phone: +1 203-432-2789. Email: [email protected]More by Menachem Elimelechhttps://orcid.org/0000-0003-4186-1563Cite this: ACS Energy Lett. 2022, 7, 9, 3032–3038Publication Date (Web):August 19, 2022Publication History Received15 July 2022Accepted5 August 2022Published online19 August 2022Published inissue 9 September 2022https://pubs.acs.org/doi/10.1021/acsenergylett.2c01615https://doi.org/10.1021/acsenergylett.2c01615newsACS PublicationsCopyright © Published 2022 by American Chemical Society. This publication is available under these Terms of Use. Request reuse permissions This publication is free to access through this site. Learn MoreArticle Views18396Altmetric-Citations14LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail PDF (3 MB) Get e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Electrical energy,Electrocatalysts,Electrolysis,Physical and chemical processes,Thin films Get e-Alerts

Industrial-scale upcycling of waste polyethylene terephthalate (PET) plastic into porous carbon globally for CO2 capture was verified as a multifunctional alternative to conventional CO2 absorption and plastic waste management technologies.

An electric vehicle is considered as one of the promising alternative transport due to its eco-friendly zero CO2 emissions. This trend causes a new environmental issue, Li-ion battery waste, and diverse plans for the used battery are suggested for preventing it. A stationary energy system connected to 1 MW photovoltaic was proposed as a repurposing strategy for the used battery. In addition, techno-economic analysis including itemized cost estimation, profitability analysis, and uncertainty analysis, was carried out to provide economic guidelines on what we need for the upcoming used battery era. Further, the optimized purchase cost for the used battery was figured out via a genetic algorithm. A levelized cost of electricity of 0.31 USD kWh-1 was obtained showing the PV cost as the most influential factor. The range of optimized purchase costs was 2,679-70,927, 3,786-100,234, and 5,747-152,162 USD according to 5, 10, and 20 years of the remaining lifetime of the used battery, respectively, and this cost varied depending on the target discounted payback period and subsidy. Finally, the repurposing of the used battery was still infeasible in terms of economic profit since 98.1%, 88.2%, and 75.2% were presented indicating a probability of negative purchase cost for the used battery. Our results show the needs of capital cost expenditure reduction via technological advancement to encourage the repurposing of the used battery.

Hydrogen has been considered as a clean energy carrier by generating electricity via fuel cells without carbon dioxide emissions; however, in the current stage, most hydrogen is produced by a steam methane reforming, emitting carbon dioxide as a by product, together. In this context, a green hydrogen production system, which is consisted of water electrolysis and a renewable energy plant, should be expanded to prepare for the upcoming hydrogen society in the future. A techno-economic analysis is carried out for green hydrogen production based on seasonal solar radiation data in the case of the single and the hybrid system, which is designed as only alkaline water electrolyzer and a combination of alkaline water electrolyzer and energy storage system. In addition, a carbon footprint analysis is performed to quantify the carbon dioxide emissions for the proposed systems. And the optimal scale of alkaline water electrolyzer and energy storage system is figured out via a genetic algorithm considering a carbon tax on emitted carbon dioxide. Based on itemized cost estimation results, 6.55 and 6.88 USD kgH(2)(-1) of unit hydrogen production costs were obtained for the case of a hybrid and a single system, respectively. Further, the results present that the hybrid system is preferred when Li-ion battery costs decrease to under 79.67 USD kWh(-1). In addition, the capital cost is a crucial factor to figure out the optimized alkaline water electrolyzer scale and energy storage system capacity that set the optimized size is important to minimize the unit hydrogen production cost. Finally, the effort to reduce the capital cost to produce the green hydrogen is necessary when increasing trend of carbon dioxide tax is considered.