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Spatial Succession for Degradation of Solid Multicomponent Food Waste and Purification of Toxic Leachate with the Obtaining of Biohydrogen and Biomethane
Jan 2022
Publication
A huge amount of organic waste is generated annually around the globe. The main sources of solid and liquid organic waste are municipalities and canning and food industries. Most of it is disposed of in an environmentally unfriendly way since none of the modern recycling technologies can cope with such immense volumes of waste. Microbiological and biotechnological approaches are extremely promising for solving this environmental problem. Moreover organic waste can serve as the substrate to obtain alternative energy such as biohydrogen (H2 ) and biomethane (CH4 ). This work aimed to design and test new technology for the degradation of food waste coupled with biohydrogen and biomethane production as well as liquid organic leachate purification. The effective treatment of waste was achieved due to the application of the specific granular microbial preparation. Microbiological and physicochemical methods were used to measure the fermentation parameters. As a result a four-module direct flow installation efficiently couples spatial succession of anaerobic and aerobic bacteria with other micro- and macroorganisms to simultaneously recycle organic waste remediate the resulting leachate and generate biogas.
Two-Layer Optimization Planning Model for Integrated Energy Systems in Hydrogen Refueling Original Station
May 2023
Publication
With the aggravation of global environmental pollution problems and the need for energy restructuring hydrogen energy as a highly clean resource has gradually become a hot spot for research in countries around the world. Facing the requirement of distributed hydrogen in refueling the original station for hydrogen transportation and other usage this paper proposes a comprehensive energy system planning model for hydrogen refueling stations to obtain the necessary devices construction the devices’ capacity decisions and the optimal operation behaviors of each device. Comparing to traditional single hydrogen producing technics in the traditional planning model the proposed model in this paper integrates both water-electrolysis-based and methanol-based manufacturing technics. A two-level optimization model is designed for this comprehensive system. The result of the numerical study shows that the proposed model can achieve a better optimal solution for distributed hydrogen production. Also it considers the single producing situation when price of one primary resource is sufficient higher than the other.
Hydrogen Carriers: Scientific Limits and Challenges for the Supply Chain, and Key Factors for Techno-Economic Analysis
Aug 2023
Publication
Hydrogen carriers are one of the keys to the success of using hydrogen as an energy vector. Indeed sustainable hydrogen production exploits the excess of renewable energy sources after which temporary storage is required. The conventional approaches to hydrogen storage and transport are compressed hydrogen (CH2 ) and liquefied hydrogen (LH2 ) which require severe operating conditions related to pressure (300–700 bar) and temperature (T < −252 ◦C) respectively. To overcome these issues which have hindered market penetration several alternatives have been proposed in the last few decades. In this review the most promising hydrogen carriers (ammonia methanol liquid organic hydrogen carriers and metal hydrides) have been considered and the main stages of their supply chain (production storage transportation H2 release and their recyclability) have been described and critically analyzed focusing on the latest results available in the literature the highlighting of which is our current concern. The last section reviews recent techno-economic analyses to drive the selection of hydrogen carrier systems and the main constraints that must be considered. The analyzed results show how the selection of H2 carriers is a multiparametric function and it depends on technological factors as well as international policies and regulations.
Green Hydrogen Production and Liquefaction Using Offshore Wind Power, Liquid Air, and LNG Cold Energy
Sep 2023
Publication
Coastal regions have abundant off-shore wind energy resources and surrounding areas have large-scale liquefied natural gas (LNG) receiving stations. From the engineering perspectives there are limitations in unstable off-shore wind energy and fluctuating LNG loads. This article offers a new energy scheme to combine these 2 energy units which uses surplus wind energy to produce hydrogen and use LNG cold energy to liquefy and store hydrogen. In addition in order to improve the efficiency of utilizing LNG cold energy and reduce electricity consumption for liquid hydrogen (LH2) production at coastal regions this article introduces the liquid air energy storage (LAES) technology as the intermediate stage which can stably store the cold energy from LNG gasification. A new scheme for LNG-LAES-LH2 hybrid LH2 production is built. The case study is based on a real LNG receiving station at Hainan province China and this article presents the design of hydrogen production/liquefaction process and carries out the optimizations at key nodes and proves the feasibility using specific energy consumption and exergy analysis. In a 100 MW system the liquid air storage round-trip efficiency is 71.0% and the specific energy consumption is 0.189 kWh/kg and the liquid hydrogen specific energy consumption is 7.87 kWh/kg and the exergy efficiency is 46.44%. Meanwhile the corresponding techno-economic model is built and for a LNGLAES-LH2 system with LH2 daily production 140.4 tons the shortest dynamic payback period is 9.56 years. Overall this novel hybrid energy scheme can produce green hydrogen using a more efficient and economical method and also can make full use of surplus off-shore wind energy and coastal LNG cold energy.
Toward Sustainability: An Overview of the Use of Green Hydrogen in the Agriculture and Livestock Sector
Aug 2023
Publication
The agro-livestock sector produces about one third of global greenhouse gas (GHG) emissions. Since more energy is needed to meet the growing demand for food and the industrial revolution in agriculture renewable energy sources could improve access to energy resources and energy security reduce dependence on fossil fuels and reduce GHG emissions. Hydrogen production is a promising energy technology but its deployment in the global energy system is lagging. Here we analyzed the theoretical and practical application of green hydrogen generated by electrolysis of water powered by renewable energy sources in the agro-livestock sector. Green hydrogen is at an early stage of development in most applications and barriers to its large-scale deployment remain. Appropriate policies and financial incentives could make it a profitable technology for the future.
Green with Envy? Hydrogen Production in a Carbon-constrained World
Jan 2024
Publication
Hydrogen is widely recognized as a key component of a decarbonized global energy system serving as both a fuel source and an energy storage medium. While current hydrogen production relies almost entirely on emissionsintensive processes two low-emissions production pathways – natural-gas-derived production combined with carbon capture and storage and electrolysis using carbon-free electricity – are poised to change the global supply mix. Our study assesses the financial conditions under which natural-gas-based hydrogen production combined with carbon capture and storage would be available at a cost lower than hydrogen produced through electrolysis and the degree to which these conditions are likely to arise in a transition to a net-zero world. We also assess the degree to which emissions reduction policies namely carbon pricing and carbon capture and storage tax credits affect the relative costs of hydrogen production derived from different pathways. We show that while carbon pricing can improve the relative cost of both green and blue hydrogen production compared with unabated grey hydrogen targeted tax credits favouring either blue or green hydrogen explicitly may increase emissions and/or increase the costs of the energy transition.
Electrochemical Devices to Power a Sustainable Energy Transition—An Overview of Green Hydrogen Contribution
Mar 2024
Publication
This work discusses the current scenario and future growth of electrochemical energy devices such as water electrolyzers and fuel cells. It is based on the pivotal role that hydrogen can play as an energy carrier to replace fossil fuels. Moreover it is envisaged that the scaled-up and broader deployment of the technologies can hold the potential to address the challenges associated with intermittent renewable energy generation. From a sustainability perspective this synergy between hydrogen and electricity from renewable sources is particularly attractive: electrolyzers convert the excess energy from renewables into green hydrogen and fuel cells use this hydrogen to convert it back into electricity when it is needed. Although this transition endorses the ambitious goal to supply greener energy for all it also entails increased demand for the materials that are essential for developing such cleaner energy technologies. Herein several economic and environmental issues are highlighted besides a critical overview regarding each technology. The aim is to raise awareness and provide the reader (a non-specialist in the field) with useful resources regarding the challenges that need to be overcome so that a green hydrogen energy transition and a better life can be fully achieved.
Look-ahead Scheduling of Energy-Water Nexus Integrated with Power2X Conversion Technologies under Multiple Uncertainties
Aug 2023
Publication
Co-optimizing energy and water resources in a microgrid can increase efficiency and improve economic performance. Energy-water storage (EWS) devices are crucial components of a high-efficient energy-water microgrid (EWMG). The state of charge (SoC) at the end of the first day of operation is one of the most significant variables in EWS devices since it is used as a parameter to indicate the starting SoC for the second day which influences the operating cost for the second day. Hence this paper examines the benefits and applicability of a lookahead optimization strategy for an EWMG integrated with multi-type energy conversion technologies and multienergy demand response to supply various energy-water demands related to electric/hydrogen vehicles and commercial/residential buildings with the lowest cost for two consecutive days. In addition a hybrid info-gap/robust optimization technique is applied to cover uncertainties in photovoltaic power and electricity prices as a tri-level optimization framework without generating scenarios and using the probability distribution functions. Duality theory is also used to convert the problem into a single-level MILP so that it can be solved by CPLEX. According to the findings the implemented energy-water storage systems and look-ahead strategy accounted for respectively 4.03% and 0.43% reduction in the total cost.
A Novel Layout for Combined Heat and Power Production for a Hospital Based on a Solid Oxide Fuel Cell
Feb 2024
Publication
This paper addresses the problem of the reduction in the huge energy demand of hospitals and health care facilities. The sharp increase in the natural gas price due to the Ukrainian–Russian war has significantly reduced economic savings achieved by combined heat and power (CHP) units especially for hospitals. In this framework this research proposes a novel system based on the integration of a reversible CHP solid oxide fuel cell (SOFC) and a photovoltaic field (PV). The PV power is mainly used for balancing the hospital load. The excess power production is exploited to produce renewable hydrogen. The SOFC operates in electrical tracking mode. The cogenerative heat produced by the SOFC is exploited to partially meet the thermal load of the hospital. The SOFC is driven by the renewable hydrogen produced by the plant. When this hydrogen is not available the SOFC is driven by natural gas. In fact the SOFC is coupled with an external reformer. The simulation model of the whole plant including the reversible SOFC PV and hospital is developed in the TRNSYS18 environment and MATLAB. The model of the hospital is calibrated by means of measured data. The proposed system achieves very interesting results with a primary energy-saving index of 33% and a payback period of 6.7 years. Therefore this energy measure results in a promising solution for reducing the environmental impact of hospital and health care facilities.
Mid-century Net-zero Emissions Pathways for Japan: Potential Roles of Global Mitigation Scenarios in Informing National Decarbonisation Strategies
Jan 2024
Publication
Japan has formulated a net-zero emissions target by 2050. Existing scenarios consistent with this target generally depend on carbon dioxide removal (CDR). In addition to domestic mitigation actions the import of low-carbon energy carriers such as hydrogen and synfuels and negative emissions credits are alternative options for achieving net-zero emissions in Japan. Although the potential and costs of these actions depend on global energy system transition characteristics which can potentially be informed by the global integrated assessment models they are not considered in current national scenario assessments. This study explores diverse options for achieving Japan's net-zero emissions target by 2050 using a national energy system model informed by international energy trade and emission credits costs estimated with a global energy system model. We found that demand-side electrification and approximately 100 Mt-CO2 per year of CDR implementation equivalent to approximately 10% of the current national CO2 emissions are essential across all net-zero emissions scenarios. Upscaling of domestically generated hydrogen-based alternative fuels and energy demand reduction can avoid further reliance on CDR. While imports of hydrogen-based energy carriers and emission credits are effective options annual import costs exceed the current cost of fossil fuel imports. In addition import dependency reaches approximately 50% in the scenario relying on hydrogen imports. This study highlights the importance of considering global trade when developing national net-zero emissions scenarios and describes potential new roles for global models.
Climate Change Mitigation Potentials of on Grid-connected Power-to-X Fuels and Advanced Biofuels for the European Maritime Transport
Jul 2023
Publication
This study proposes a country-based life-cycle assessment (LCA) of several conversion pathways related 10 to both on grid-connected Power-to-X (PtX) fuels and advanced biofuel production for maritime transport 11 in Europe. We estimate the biomass resource availability (both agricultural and forest residues and 12 second-generation energy crops from abandoned cropland) electricity mix and a future-oriented 13 prospective LCA to assess how future climate change mitigation policies influence the results. Our results 14 indicate that the potential of PtX fuels to achieve well-to-wake greenhouse gas intensities lower than 15 those of fossil fuels is limited to countries with a carbon intensity of the electricity mix below 100 gCO2eq kWh-1 16 . The more ambitious FuelEU Maritime goal could be achieved with PtX only if connected to electricity sources below ca. 17 gCO2eq kWh-1 17 which can become possible for most of the national 18 electricity mix in Europe by 2050 if renewable energy sources will become deployed at large scales. For 19 drop-in and hydrogen-based biofuels biomass residues have a higher potential to reduce emissions than 20 dedicated energy crops. In Europe the potentials of energy supply from all renewable and low-carbon 21 fuels (RLFs) range from 32-149% of the current annual fuel consumption in European maritime transport. 22 The full deployment of RLFs with carbon capture and storage technologies could mitigate up to 184% of 23 the current well-to-wake shipping emissions in Europe. Overall our study highlights how the strategic use 24 of both hydrogen-based biofuels and PtX fuels can contribute to the climate mitigation targetsfor present 25 and future scenarios of European maritime transport.
Roles of Bioenergy and Green Hydrogen in Large Scale Energy Storage for Carbon Neutrality
Aug 2023
Publication
A new technical route to incorporate excess electricity (via green hydrogen generation by electrolysis) into a biorefinery to produce modern bioenergy (advanced biofuels) is proposed as a promising alternative. This new route involves storing hydrogen for mobile and stationary applications and can be a three-bird-one-stone solution for the storage of excess electrical energy storage of green hydrogen and high-value utilization of biomass.
Review of Fuel Cell Technologies and Applications for Sustainable Microgrid Systems
Aug 2020
Publication
The shift from centralized to distributed generation and the need to address energy shortage and achieve the sustainability goals are among the important factors that drive increasing interests of governments planners and other relevant stakeholders in microgrid systems. Apart from the distributed renewable energy resources fuel cells (FCs) are a clean pollution-free highly efficient flexible and promising energy resource for microgrid applications that need more attention in research and development terms. Furthermore they can offer continuous operation and do not require recharging. This paper examines the exciting potential of FCs and their utilization in microgrid systems. It presents a comprehensive review of FCs with emphasis on the developmental status of the different technologies comparison of operational characteristics and the prevailing techno-economic barriers to their progress and the future outlook. Furthermore particular attention is paid to the applications of the FC technologies in microgrid systems such as grid-integrated grid-parallel stand-alone backup or emergency power and direct current systems including the FC control mechanisms and hybrid designs and the technical challenges faced when employing FCs in microgrids based on recent developments. Microgrids can help to strengthen the existing power grid and are also suitable for mitigating the problem of energy poverty in remote locations. The paper is expected to provide useful insights into advancing research and developments in clean energy generation through microgrid systems based on FCs.
Caveats of Green Hydrogen for Decarbonisation of Heating in Buildings
Oct 2023
Publication
Hydrogen (H2) has rapidly become a topic of great attention when discussing routes to net-zero carbon emissions. About 14% of CO2 emissions globally are directly associated with domestic heating in buildings. Replacing natural gas (NG) with H2 for heating has been highlighted as a rapid alternative for mitigating these emissions. To realise this not only the production challenges but also potential obstacles in the transmission/distribution and combustion of H2 must be technically identified and discussed. This review in addition to delineating the challenges of H2 in NG grid pipelines and H2 combustion also collates the results of the state-of-the-art technologies in H2-based heating systems. We conclude that the sustainability of water and renewable electricity resources strongly depends on sizing siting service life of electrolysis plants and post-electrolysis water disposal plans. 100% H2 in pipelines requires major infrastructure upgrades including production transmission pressurereduction stations distribution and boiler rooms. H2 leakage instigates more environmental risks than economic ones. With optimised boilers burning H2 could reduce GHG emissions and obtain an appropriate heating efficiency; more data from boiler manufacturers must be provided. Overall green H2 is not the only solution to decarbonise heating in buildings and it should be pursued abreast of other heating technologies.
Techno-economic Analysis of Green-H2@Scale Production
Sep 2023
Publication
The International Energy Agency (IEA) established the "H2 Implementing Agreement (HIA)" to promote H2 transition in various economic sectors. Today less than one percent of the world's H2 production is “Green”. Lack of regulations high production costs and inadequate infrastructure are significant impediments. The U.S. Department of Energy set a "111-target" which translates into $1/kg-H2 in the next decade. Many countries in the Middle East and North Africa (MENA) region have announced ambitious plans to produce green H2. Through techno-economic metrics and the impact of economies of scale this study investigates H2@Scale production. H2 Production Analysis and the System Advisor Model developed by the U.S. Department of Energy were used for analysis. The results demonstrate a significant decrease in the levelized cost of H2 (LCOH) when the production volume is scaled up. It was determined that the key cost drivers are capital cost energy installed balance of the plant and mechanical and electrical subsystems. The studied location is found promising for scaled production and developing its commodity status. The findings could serve as a benchmark for key stakeholders investors policymakers and the developer of relevant strategies in the infrastructure and H2 value chain.
Can an Energy Only Market Enable Resource Adequacy in a Decarbonized Power System? A Co-simulation with Two Agent-based-models
Feb 2024
Publication
Future power systems in which generation will come almost entirely from variable Renewable Energy Sources (vRES) will be characterized by weather-driven supply and flexible demand. In a simulation of the future Dutch power system we analyze whether there are sufficient incentives for market-driven investors to provide a sufficient level of security of supply considering the profit-seeking and myopic behavior of investors. We cosimulate two agent-based models (ABM) one for generation expansion and one for the operational time scale. The results suggest that in a system with a high share of vRES and flexibility prices will be set predominantly by the demand’s willingness to pay particularly by the opportunity cost of flexible hydrogen electrolyzers. The demand for electric heating could double the price of electricity in winter compared to summer and in years with low vRES could cause shortages. Simulations with stochastic weather profiles increase the year-to-year variability of cost recovery by more than threefold and the year-to-year price variability by more than tenfold compared to a scenario with no weather uncertainty. Dispatchable technologies have the most volatile annual returns due to high scarcity rents during years of low vRES production and diminished returns during years with high vRES production. We conclude that in a highly renewable EOM investors would not have sufficient incentives to ensure the reliability of the system. If they invested in such a way to ensure that demand could be met in a year with the lowest vRES yield they would not recover their fixed costs in the majority of years.
A Comparative Study on Energy Efficiency of the Maritime Supply Chains for Liquefied Hydrogen, Ammonia, Methanol and Natural Gas
Jun 2023
Publication
To cope with climate change emerging fuels- hydrogen ammonia and methanol- have been proposed as promising energy carriers that will replace part of the liquefied natural gas (LNG) in future maritime scenarios. Energy efficiency is an important indicator for evaluating the system but the maritime supply system for emerging fuels has yet to be revealed. In this study the energy efficiency of the maritime supply chain of hydrogen ammonia methanol and natural gas is investigated considering processes including production storage loading transport and unloading. A sensitivity analysis of parameters such as ambient temperature storage time pipeline length and sailing time is also carried out. The results show that hydrogen (2.366%) has the highest daily boil-off gas (BOG) rate and wastes more energy than LNG (0.413%) with ammonia and methanol both being lower than LNG. The recycling of BOG is of great importance to the hydrogen supply chain. When produced from renewable energy sources methanol (98.02%) is the most energy efficient followed by ammonia with hydrogen being the least (89.10%). This assessment shows from an energy efficiency perspective that ammonia and methanol have the potential to replace LNG as the energy carrier of the future and that hydrogen requires efficient BOG handling systems to increase competitiveness. This study provides some inspirations for the design of global maritime supply systems for emerging fuels.
Routes for Hydrogen Introduction in the Industrial Hard-to-Abate Sectors for Promoting Energy Transition
Aug 2023
Publication
This paper offers a set of comprehensive guidelines aimed at facilitating the widespread adoption of hydrogen in the industrial hard-to-abate sectors. The authors begin by conducting a detailed analysis of these sectors providing an overview of their unique characteristics and challenges. This paper delves into specific elements related to hydrogen technologies shedding light on their potential applications and discussing feasible implementation strategies. By exploring the strengths and limitations of each technology this paper offers valuable insights into its suitability for specific applications. Finally through a specific analysis focused on the steel sector the authors provide in-depth information on the potential benefits and challenges associated with hydrogen adoption in this context. By emphasizing the steel sector as a focal point the authors contribute to a more nuanced understanding of hydrogen’s role in decarbonizing industrial processes and inspire further exploration of its applications in other challenging sectors.
Thermal Sprayed Protective Coatings for Bipolar Plates of Hydrogen Fuel Cells and Water Electrolysis Cells
Mar 2024
Publication
As one core component in hydrogen fuel cells and water electrolysis cells bipolar plates (BPs) perform multiple important functions such as separating the fuel and oxidant flow providing mechanical support conducting electricity and heat connecting the cell units into a stack etc. On the path toward commercialization the manufacturing costs of bipolar plates have to be substantially reduced by adopting low-cost and easy-to-process metallic materials (e.g. stainless steel aluminum or copper). However these materials are susceptible to electrochemical corrosion under harsh operating conditions resulting in long-term performance degradation. By means of advanced thermal spraying technologies protective coatings can be prepared on bipolar plates so as to inhibit oxidation and corrosion. This paper reviews several typical thermal spraying technologies including atmospheric plasma spraying (APS) vacuum plasma spraying (VPS) and high-velocity oxygen fuel (HVOF) spraying for preparing coatings of bipolar plates particularly emphasizing the effect of spraying processes on coating effectiveness. The performance of coatings relies not only on the materials as selected or designed but also on the composition and microstructure practically obtained in the spraying process. The temperature and velocity of in-flight particles have a significant impact on coating quality; therefore precise control over these factors is demanded.
Shorter Message, Stronger Framing Increases Societal Acceptance for Hydrogen
Feb 2024
Publication
With the question of ‘can short messages be effective in increasing public support for a complex new technology (hydrogen)?‘ this study uses a representative national survey in Australia to analyze the differences and variations in subjective support for hydrogen in response to four differently framed short messages. The findings of this study show that short messages can increase social acceptance but the effects depend on how strongly the message is framed in terms of its alignment with either an economic or environmental values framework. Furthermore the effects depend on the social and cultural context of the receiver of the message.
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