Renewable-based Energy Research Articles

Decarbonized green hydrogen production by sorption-enhanced biomass gasification: An integrated techno-economic and environmental evaluation

Deployment of innovative renewable-based energy applications are critical for reducing CO2 emissions and achieving global climate neutrality. This work evaluates the production of decarbonized green H2 based on sorption-enhanced biomass (sawdust) gasification. The calcium-based sorbent was evaluated in a looping cycle configuration as sorption material to enhance both the CO2 capture rate and the energy-efficient hydrogen production. The investigated concept is set to produce 100 MWth high purity hydrogen (>99.95% vol.) with very high decarbonization yield (>98–99%) using woody biomass as a fuel. Conventional biomass (sawdust) gasification systems with and without CO2 capture capability are also assessed for the calculation of energy and economic penalties induced by decarbonization. The results show that the decarbonized green hydrogen manufacture by sorption-enhanced biomass gasification shows attractive performances e.g., high overall energy efficiency (about 50%), reduced energy and economic penalties for almost total decarbonization (down to 8 net efficiency points), low specific carbon emissions at system level (lower than 7 kg/MWh) and negative CO2 emission for whole biomass value chain (about −518.40 kg/MWh). However, significant developments (e.g., improving reactor design and fuel/sorbent conversion yields, reducing sorbent make-up etc.) are still needed to advance this innovative concept from present level to industrial sizes.

Exploring Iron-Containing Electrodes for Use as Negative Electrodes of All-Iron Redox Flow Batteries

The transition towards a renewables-based energy economy is motivated by pressing environmental concerns and economic growth rates. This new energy paradigm necessitates efficient, robust and cost-effective, large-scale energy storage systems. Aqueous, all-iron redox flow batteries (AIRFBs) are a promising contender for large-scale energy storage, motivated by their reliance on environmentally friendly and abundant raw materials, their intrinsic safety, and projected high energy density (ca. 135 Ah L-1) [1]. However, the performance and lifetime of state-of-the-art AIRFBs are greatly limited the poor kinetics and uneven plating taking place in the negative half-cell. Traditionally, the electrochemical stack leverages carbon fiber-based electrodes (e.g. felts), which provide moderate surface area for reaction but suffer from sluggish kinetics and plated layers of poor quality [2].Hereby, we explore the use of iron-based (e.g. pure iron, steel types 302, 316, 420) electrode alternatives to overcome the challenges of prevalent carbon fiber electrodes or pure iron. Steels have been investigated for numerous electrochemical systems, such as (microbial) fuel cells, electrolyzers and various types of batteries, displaying high performance and excellent chemical stability, robust mechanical properties and low production costs [3]. More precisely, in this work we investigate iron-based electrodes as a substitute for conventional carbon felts due to their enhanced kinetic activity in the negative half cell [Fe2+(aq)|Fe(s)]. Firstly, different metal electrodes were tested in flow-by configuration to obtain their polarization performance. Employing a flat electrode of pure alpha-iron as a baseline, we find that it displays balanced behavior between charging and discharging mode, although it exhibits very limited utilization of its projected gravimetric capacity[4]. Following this, we test a set of steel sheets of different nature, that is, ferritic, martensitic and austenitic, which contain various alloying elements (e.g., Cr, Ni, Mn, Mo, etc.) in different ratios, resulting in different electrochemical performance. We find that materials containing low to moderate Ni:Cr ratios result in enhanced iron plating and stripping kinetics, with increases ranging from ~20 to ~60% with respect to the pure alpha-iron electrode. Furthermore, we observe that the crystallographic structure of austenitic materials tend to favor reactions involving iron ions, as opposed to martensitic structures of which feature higher solid-to-gas surface energy, which favor the competing hydrogen evolution reaction [5]. We additionally investigate advanced three-dimensional structures in a symmetric, flow-through configuration, by selecting the best performing steel composition. By screening various fiber arrangements, we aim to elucidate the structural effects on mass transfer and overall cell performance.Overall, we studied the interplay between the composition and architecture of different metal-based electrodes. We hope that these findings will help shed light on their potential to improve the performance of the challenging iron plating-stripping reaction and ultimately introduce them in a full cell system to enable higher capacity and rate performance of the promising all-iron flow battery Acknowledgments IGG gratefully acknowledges financial support by “la Caixa Foundation” (ID 100010434) under the fellowship number LCF/BQ/EU20/11810076. AFC gratefully acknowledges funding by the European Union (ERC, FAIR-RFB, ERC-2021-STG 101042844). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them.

Design of a hybrid solar and biomass-based energy system integrated with near-zero energy building: Techno-environment investigation and multicriteria optimization

The current research aims to meet the energy needs of a group of residential buildings in Norway with the least amount of carbon dioxide emission and the greatest amount of renewable energy. The supply side based on the renewable renewable-based energy system is planned and scaled using the real-time data use of domestic hot water (DHW), heating and electricity necessary for the buildings. PVT panels are used in the hybrid solar and biomass-based energy systems to produce both the DHW requirements and the electricity production. The digester is used with the heat pump, which generates heat. A double-effect absorption refrigeration system is also utilized to provide the necessary cooling requirements. On the supply side, the management of the heat streams and the redirection of flows are done using a rule-based regulating system. The whole plant's size is supplied, and the dynamic energy simulation is run. The primary deciding criteria for heating the buildings are the costs of electricity and biomass. The whole system is then optimized depending on operating circumstances, and the outcomes are compared to the design point. PVT may be used to create more than 80 % of the yearly DHW. Furthermore, summertime radiation accounts for 64.8 % of cooling output since it is more intense and may be converted into cooling energy. Digester/CC also contributes 66.55 % of the building's heating, showing that the designers should rely on biomass as wintertime energy costs are higher. The parametric study demonstrates that increasing PVT time and tank capacity has varied effects on efficiency and emissions. Also, On winter days, there was a significant drop in renewable energy generation from summer to autumn, from 82.7 MWh to 28.52 MWh. The optimization results show that at the TOPSIS point, the total cost, efficiency, and emission index are 9.73 $/hr, 36.8 %, and 7.75 kg/MWh, respectively.

Machine learning optimization and 4E analysis of a CCHP system integrated into a greenhouse system for carbon dioxide capturing

The world has seen an increase in the popularity of renewable-based energy systems. However, because of their erratic nature, fossil fuels cannot be entirely phased out. Utilizing carbon dioxide in greenhouses close to power plants and generating extra power electricity from dissipated thermal energy are appealing strategies that cause us to have a cleaner environment and affordable power electricity. To exploit the high enthalpy of expelled gases from a gas turbine, the gas turbine was coupled with an absorption refrigerant cycle and an organic Rankine cycle and analyzed. Additionally, a deep artificial neural network method was used to calculate all functions in a rapid optimization and accurate 4E analysis. The carbon dioxide emissions subsided from 0.9183 to 0.41 kg CO2/s, and the optimization time improved 257 times after using the trained machine learning model. An adsorption technique for CO2 separation is used for the proposed system because of its lower energy consumption. The maximum exergy and energy efficiencies were attained at 36.71 % and 49.2 %, respectively, and parametric studies are being assessed. Due to increases in harvests and efficiencies, the net annual interest has increased by 21.8 %, up to 22.5 million dollars.

Demonstrating clean energy transition scenarios in sector-coupled and renewable-based energy communities.

Energy communities facilitate several advantages, including energy autonomy, reduced greenhouse gas emissions, poverty mitigation, and regional economic development. They also empower citizens with decision-making and co-ownership prospects in community renewable projects. Integrating renewable energy sources and sector coupling is a crucial strategy for flexible energy systems. However, demonstrating clean energy transition scenarios in these communities presents challenges, including technology integration, flexibility activation, load reduction, grid resilience, and business case development. Based on the system of systems approach, this paper introduces a 4-step funnel approach and a 4-step reverse funnel approach to systematically specify and detail demonstration scenarios for energy community projects. The funnel approach involves four steps. First, it selects demonstration scenarios promoting energy-efficient state-of-the-art renewable technologies and storage systems, flexibility through demand side management techniques, reduced grid dependence, and economic viability. Second, it lists all existing and planned project technologies, analysing energy flows. Third, it plans actions at different levels to implement the demonstration scenarios. Fourth, it validates the strategies using key performance indicators (KPI) to quantify the effectiveness of the planned measures. Furthermore, the reverse funnel approach delves deeper into the demonstration scenarios. The four steps involve identifying stakeholder perspectives, describing scenario scopes, listing conditions for realisation, and outlining business models, including value chains and economic assumptions. This approach provides a detailed analysis of the demonstration scenarios, considering actors, objectives, boundary conditions, and business assumptions. The methodologies are exemplified in three diverse European energy communities extending across residential, commercial, tertiary, and industrial establishments, allowing power-to-x and sector coupling opportunities. The paper also suggested thirteen KPIs for validating renewable-focused energy community projects. Finally, the paper recommends increased collaboration between energy communities, knowledge sharing, stakeholder engagement, transparent data collection and analysis, continuous feedback, and method improvement to mitigate policy, technology, business, and market uncertainties.

Transition to a 100 % renewable power supply in galapagos islands: Long-term and short-term analysis for optimal operation and sizing of grid upgrades

Owing to their remarkable biodiversity and endemic ecosystems, the Galapagos Islands are one of the most important World Heritage sites. However, due to their isolation and remote geographical location, around 83.6 % of the energy supply in Galapagos relies on the use of fossil fuels, which are polluting the air, the land and the sea, therefore requiring an adequate energy planning for the efficient transition towards a more sustainable and environmentally friendly energy sources. Although there were several previous studies of the decarbonization of Galapagos’ energy supply, there is a need for a more comprehensive approach that will combine planning (long-term) and operational (short-term) analysis to evaluate both, the future investment plans and performance of evolving energy supply system, as well as to provide an in-depth evaluation of required system upgrades in terms of locally available renewable energy resources. In order to fill this gap, this paper presents results of two different studies for the optimal decarbonization and transition to a 100 % renewable energy supply of the Galapagos Islands, giving details on the development of modelling tools required for the analysis of different scenarios and various techno-economic constraints. The first study is used for a long-term for analysing and strategic planning of the energy matrix until 2050, starting from existing power plants and following projections for the deployment of new renewable-based energy generation and dedicated energy storage sources to determine the optimal sizing and timing of required grid upgrades. The second study is a short-term annual performance analysis, which considers days of minimum, average and maximum available renewable energy resources to optimize system operation with existing and additional renewable energy generation and storage sources that will minimize, or keep at a certain target level, contributions from diesel generation. The two presented studies complement each other, allowing to evaluate transition to a 100 % renewable energy supply in Galapagos from both the investment/planning perspective and from the operational point of view. The results of two studies are very close in terms of the sizes of required new PV generation and associated energy storage in Baltra-Santa Cruz islands by 2050 (around 50 MW of PV and 145 MW of storage), with the short-term study allowing to identify curtailed PV generation (on average around 140 MWh per day) as an opportunity to connect new controllable loads, and with the long-term study allowing to evaluate interim targets for decarbonization pathways to Net Zero by 2050 through the related techno-economic optimization.

100% renewable heat supply in Berlin by 2050 – A model-based approach

The energy crisis posed major challenges, especially for the heating sector. The European gas price increased from 16€/MWh in March 2021 to 227€/MWh in March 2022, which led to a debate in Germany around reshaping the heat supply to decrease energy import dependence. However, many actors on the heating market are reluctant to make the necessary investments to reduce dependence on natural gas. Although, independence of fossil energy imports by 2050 would be possible with a switch to a 100% renewable heat supply for Berlin.Based on the linear open-source energy system model GENeSYS-MOD, a 100% renewable-based energy system is modeled. GENeSYS-MOD is extended to model district heating, which is crucial for Berlin's heat supply. Furthermore, the modeling of heat pumps and a data set for Berlin is revised.The modeling considers the tightened climate protection targets, which means a 95% CO2 reduction by 2045 compared to 1990. By 2050, 100% of the transport, industry, electricity, and building sectors` emissions are mitigated.The results suggest the immediate exploitation of the existing renewable energy potential and seasonal heat storages, as well as a necessity for a major increase in renovation rates. The upcoming coal phase-out in Berlin in 2030 should be met by a mix of heat pumps and biomass. If heat pump resources are exhausted, direct electric heating is deployed as last resort option.

Methodologies for the design of positive energy districts: A scoping literature review and a proposal for a new approach (PlanPED)

Cities can substantially contribute to European Green Deal targets by accelerating their transition towards smarter, more efficient, and renewable-based energy models. In that context, European cities need to increase their self-sufficiency and the resilience of their energy system especially through the promotion of district and neighbourhood scale energy projects such as positive energy districts (PEDs). Despite the increasing interest for PEDs experienced in the last years, their deployment is currently hindered by the absence of an energy planning culture and the lack of adequately skilled personnel in cities. Indeed, there is a strong need for practical tools and guidelines that support practitioners in the design and implementation of PEDs. In that context, the present paper introduces PlanPED, a framework for the conception of methodologies for PED planning, design, and implementation, to support municipalities in their energy transition. PlanPED aims at providing a multiple perspective approach based on the most important elements from existing methodologies. In that sense, the paper begins with an overview of the state of the art, leading to the identification of trends, gaps, and good practices of current research. Then, based on this analysis, the novel framework PlanPED is introduced. It consists of three interconnected workflows that, if followed, enable to know which steps and resources need to be put into practice to initiate the transition towards PED, while recognizing the variability of contexts and necessities. By doing so, PlanPED seeks to facilitate the elaboration of tailored and practical roadmaps for the deployment of PEDs in cities.

The Storage Process of Electric Energy Produced from Renewable Sources from Hydrogen to Domestic Hot Water Heating

The expansion of renewable electricity storage technologies, including green hydrogen storage, is spurred by the need to address the high costs associated with hydrogen storage and the imperative to increase storage capacity. The initial section of the paper examines the intricacies of storing electricity generated from renewable sources, particularly during peak periods, through green hydrogen. Two primary challenges arise: firstly, the complexity inherent in the storage technology and its adaptation for electricity reproduction; and secondly, the cost implications throughout the technological chain, resulting in a significant increase in the price of the reproduced energy. Electric energy storage emerges as a pivotal solution to accommodate the growing proportion of renewable energy within contemporary energy systems, which were previously characterized by high stability. During the transition to renewable-based energy systems, optimizing energy storage technology to manage power fluctuations is crucial, considering both initial capital investment and ongoing operational expenses. The economic analysis primarily focuses on scenarios where electricity generated from renewable sources is integrated into existing power grids. The subsequent part of this paper explores the possibility of localizing excess electricity storage within a specific system, illustrated by domestic hot water.

Role of smart charging of electric vehicles and vehicle-to-grid in integrated renewables-based energy systems on country level

The energy transition based on variable renewable energy sources raises concerns on satisfying the electricity demand at all hours of a year, which is amplified by the ongoing energy system electrification. Balancing variable electricity supply and inelastic demand requires additional sources of flexibility in the system: flexible electricity generation, energy storage, grids, flexible demand, and overall sector coupling. Electrification of transport increases the electricity demand; however, it offers the opportunity to use additional low-cost flexibility from electric vehicles batteries. The LUT Energy System Transition Model was modified to model the smart charging and vehicle-to-grid functionality of electric vehicles in integrated energy systems. The results show that, in countries with a large fleet of electric vehicles, smart charging and vehicle-to-grid allow for a substantial reduction of energy storage requirements, reducing the electricity and heat storage capacity by 35% and 25%, respectively and leading to 4% lower system cost. Flexible operation of electrolysers required for e-fuels synthesis have a similar effect and, in combination with smart charging and vehicle-to-grid, can lead to 8% lower system cost. The impact of vehicle-to-grid naturally depends on assigned operational cost; however, it contributes to system cost reduction even at high costs of 50 or 100 €/MWh.

An Improved High Gain Continuous Input Current Quadratic Boost Converter for Next–Generation Sustainable Energy Application

With the rapid transformation from fossil fuel-based energy systems to renewable-based energy systems the application of a high gain boost DC-DC converter is becoming the main attraction due to its wide range of numerous applications. This specific study presents an improved high gain non isolated quadratic boost DC-DC converter (QBC) with voltage gain three times of the quadratic boost converter. The proposed non-isolated category topology is the modified version of the quadratic boost converter where the 2nd inductor of the QBC is replaced by a voltage multiplier cell (VMC) and a switch capacitor network is integrated with the VMC to increase the voltage gain as well as to reduce the switch’s voltage stress. Moreover, the continuous input current and common ground feature of this proposed circuit configuration have shaped its potential application by making it advantageous over other non-isolated based high gain boost converters. To support its feasibility a rated power of 150 W prototype is developed after validating the results by Plecs software. The voltage gain offered by this proposed circuit configuration is justified by experimental results and the software simulation. A comprehensive analysis and components design is also formulated and documented in this study.

Distribution and transmission coordinated dispatch under joint electricity and carbon day-ahead markets

Worldwide efforts to attain a more renewable-based energy matrix have led to the creation of carbon emission-related markets. Simultaneously, the increasing penetration, mostly of renewable-based sources, in distribution networks may allow distribution system operators (DSOs) to change their traditional participation in wholesale markets as passive buyers. Over the last few years, many authors have investigated and proposed optimization models for the strategic participation of DSOs in electricity markets. Nonetheless, proposals regarding the DSO as a strategic agent in both electricity and carbon-related markets are rare. In this paper, we propose a stochastic bilevel formulation to address this gap. The economic and operational constraints of each stakeholder are considered in the model. Additionally, the problem is written in a convex formulation for which finite convergence to optimality is guaranteed. The formulation was tested for a 14-node transmission system and a 34-node distribution system in which dispatchable and non-dispatchable energy sources, energy storage systems, and demand response units are installed. The results show the DSO’s capacity to place strategic bids in both market environments to maximize its profit, which features intentionally taking financial losses in the carbon allowance market to maximize the overall profit due to the income maximization in the electricity market. Finally, an additional case study with a 123-node distribution system shows the proposed method’s scalability.

DESIGN AND NUMERICAL INVESTIGATIONS OF AN AFTERBURNER SYSTEM USING METHANE-HYDROGEN BLENDS

The gas turbine industry strongly committed to develop gas turbines operating with 100% hydrogen till 2030, such fully supporting the transformation of the European natural gas grid into a renewable-based energy system by overcoming technical challenges and ensuring that this transformation takes place swiftly. By extending the fuel capabilities of gas turbines to hydrogen, their role can become predominant in the energy transition period but also in long-term energy strategies. In combined cycle configuration (CCGT), gas turbines are already the cleanest form of thermal power generation. For the same amount of electricity generated, gas turbines running on natural gas emit 50% less CO2 emissions than coal-fired power plants. Mixing renewable gas (e.g., green hydrogen, biogas) with natural gas enables further reduction in net CO2 emissions. In this paper pure hydrogen and blends of hydrogen methane will be studied as fuel in order to predict the behavior of afterburner system with a new designed geometry.

Developing a new flexibility-oriented model for generation expansion planning studies of renewable-based energy systems

This paper presents a flexibility-oriented generation expansion planning (GEP) model with the goal of increasing renewable energy penetration. The model incorporates GEP and unit commitment while considering improved reserve requirements. Utilizing GEP and unit commitment results in considering short-term operational constraints. Furthermore, given the increase in renewable portfolio standards (RPS) and the need for accurate reserve requirements determination, it is essential to consider improved reserve requirements in the proposed model. Moreover, this model utilizes a metric that measures power system flexibility deficiency and leads to flexible power system expansion by integrating it into the objective function. The flexibility-oriented GEP model is developed using mixed-integer linear programming and applied to a scaled-sized case study representing the national power system of Iran with a twenty-year planning horizon. The results show that neglecting improved reserve requirements leads to plans short on flexibility, and considering these requirements substantially declines the upward flexibility violation costs by 68% under the base scenario and 87% under increasing non-hydro RPS scenario. Furthermore, using the flexibility metric coupled with improved reserve requirements changes the optimal path for power system expansion and reduces the risk of flexibility deficiency. Also, increasing RPS by 35% would strongly depend on developing fast-response dispatchable generation units in the years before renewable energy resources expansion; however it doesn’t impose a significant extra cost of planning and the total cost will increase just by 9.43%.

Repurposing End-of-Life Coal Mines with Business Models Based on Renewable Energy and Circular Economy Technologies

This paper presents a methodology to select the most exciting business models based on renewable energy and circular economy technologies within end-of-life coal mines to help develop a renewable-based energy sector, promote sustainable local economic growth, and maximise the number of green and quality jobs. To achieve this goal, first, a structural analysis was developed to select the technical variables that better identify this complex system. Second, a morphological analysis allowed the construction of the scenario space. Third, a multicriteria assessment was developed to achieve this goal, based on the previously assessed relevant scenarios, considering the European Green Deal policies, technical variables that characterise end-of-life coal mine environments, technology readiness level, the European taxonomy, synergistic potentials, contributions to the circular economy, and sector coupling. Finally, result indicators were selected to analyse the alternative options derived from the justification approach, considering the targets set by the European Green Deal and related taxonomy and the regional policy indicators for the Just Transition Fund. The results show that eco-industrial parks with virtual power plants represent the most appropriate business model choice, according to the scoring given to the different aspects. They may be complemented by a hydrogen production plant, provided that specific economic subventions are obtained to achieve balanced financial results.

Demonstrating clean energy transition scenarios in sector-coupled and renewable-based energy communities

Background Energy communities facilitate several advantages, including energy autonomy, reduced greenhouse gas emissions, poverty mitigation, and regional economic development. They also empower citizens with decision-making and co-ownership prospects in community renewable projects. Integrating renewable energy sources and sector coupling is a crucial strategy for flexible energy systems. However, demonstrating clean energy transition scenarios in these communities presents challenges, including technology integration, flexibility activation, load reduction, grid resilience, and business case development. Methods Based on the system of systems approach, this paper introduces a 4-step funnel approach and a 4-step reverse funnel approach to systematically specify and detail demonstration scenarios for energy community projects. The funnel approach involves four steps. First, it selects demonstration scenarios promoting energy-efficient state-of-the-art renewable technologies and storage systems, flexibility through demand side management techniques, reduced grid dependence, and economic viability. Second, it lists all existing and planned project technologies, analysing energy flows. Third, it plans actions at different levels to implement the demonstration scenarios. Fourth, it validates the strategies using key performance indicators (KPI) to quantify the effectiveness of the planned measures. Furthermore, the reverse funnel approach delves deeper into the demonstration scenarios. The four steps involve identifying stakeholder perspectives, describing scenario scopes, listing conditions for realisation, and outlining business models, including value chains and economic assumptions. Results This approach provides a detailed analysis of the demonstration scenarios, considering actors, objectives, boundary conditions, and business assumptions. The methodologies are exemplified in three diverse European energy communities extending across residential, commercial, tertiary, and industrial establishments, allowing power-to-x and sector coupling opportunities. The paper also suggested thirteen KPIs for validating renewable-focused energy community projects. Conclusions Finally, the paper recommends increased collaboration between energy communities, knowledge sharing, stakeholder engagement, transparent data collection and analysis, continuous feedback, and method improvement to mitigate policy, technology, business, and market uncertainties.

Future of sustainable renewable-based energy systems in smart city industry: Interruptible load scheduling perspective

As the industrial and household loads continue to grow in smart cities, power supply and usage balance is getting more challenging. The increase in supply-side energy production is one method of alleviating peak demand proposed by a few investigations. As peak loads last for a short time, additional installations might be required. In addition, facilities that store energy can be used to reduce peak demand. As a consequence of the previous investigation, interruptible load regulation was not taken into account in optimizing system performance. The regulation of interruptible loads can greatly reduce system peak loads in smart city and within the concept of microgrids (MGs). The study proposes an interruptible load scheduling (ILS) scheme that considers consumer subsidy rates with the goal of reducing the peak load of the MG and its operating prices. To this end, a digital twin is developed in which the consumer interruption load time and minimal per-day load decrease restrictions have been completely met in the scheme. The ILS model is solved using a combination of the Min-Conflict Algorithm and the Gray Wolf Optimization Algorithm. Furthermore, simulations demonstrate the efficiency of the suggested algorithm and the show the substantial benefits of the scheme in reducing peak loads and operating prices in smart cities.

Mitigating climate change for negative CO2 emission via syngas methanation: Techno-economic and life-cycle assessments of renewable methane production

Recently, electric fuels (E-fuel), which are the chemicals produced from the conversion of renewable-based hydrogen (H2), are actively being developed as a sustainable energy carrier. Renewable methane is particularly a promising alternative to fossil-based natural gas, which can be produced from CO2 or syngas methanation. In this work, techno-economic assessment (TEA) and life-cycle assessment (LCA) for renewable methane production are performed through syngas methanation, where CO2 is collected using direct air capture (DAC) and syngas is produced by solid oxide electrolysis (SOE) with renewable-based electricity. This research considers the different technical, economic, and environmental performances of the systems for renewable methane production. A favorable reduction in a maximum of 23.3% of CH4 production cost is observed by the scale-up effects of SOE system from 1 MW to 10 MW. TEA draws the conclusion that economic infeasibility is proved at the current level, but additional research and improvement of SOE system and a plunge in renewable electricity prices can lead to the economic equivalent of conventional natural gas. Furthermore, given that certain energy resources with low energy intensity (0.0394 kg CO2-eq MJ−1) are integrated with SOE system for methane production, the LCA results that renewable methane production at a large scale has a potential to access negative CO2 emissions and accelerate climate change mitigation. Consequently, it is concluded that syngas methanation with renewable-based energy systems and DAC can make a considerable opportunity for climate change mitigation under the assumption that SOE system and renewable energy are significantly improved.

Do natural resources ensure access to sustainable renewable energy in developing economies? The role of mineral resources in a resources-energy novel setting

Natural resource rents offer both opportunities and challenges. Effectively harnessing these rents while mitigating the associated risks is crucial for promoting sustainable economic development, environmental conservation, and social welfare in these nations. This study highlights the role of natural resource rents, economic activity, and energy efficiency on renewable electricity output in case of BRICS countries from 1988 to 2021. Investigating the nexus between resources' rents on renewable electricity output in BRICS countries is crucial because each of the BRICS countries has unique energy profiles and large natural resource reserves. The significant results of the Westerlund cointegration test provide strong evidence of a long-term association amongst natural resource rents, GDP, energy efficiency, and renewable electricity output in the BRICS countries. This finding highlights the importance of understanding and considering the long-term dynamics and interdependencies among these variables when formulating policies and strategies for sustainable energy development. The estimates of the quantile regression approach suggest that coal rents and mineral rents negatively affect renewable electricity output. On the contrary, energy efficiency, forest rents, oil rents, and GDP positively affect renewable electricity output. The findings underscore the need for tailored policies by addressing each country's key challenges and opportunities. By leveraging natural resource rents, promoting sustainable economic growth, and enhancing energy efficiency, BRICS countries can accelerate their transition to a more sustainable and renewable-based energy system, contributing to global climate change mitigation efforts.

Hydrogen production via renewable-based energy system: Thermoeconomic assessment and Long Short-Term Memory (LSTM) optimization approach

A clean and carbon-free energy market can be more sustainable and safer that can be approaches by investing on hydrogen energy. Further, a renewable energy-driven energy production cycle coupled with an energy storage option is of major significance. In the present article, a hybrid process based on geothermal and solar energies is conceptually designed and simulated. The process is comprised of a solar-organic Rankine cycle (ORC) unit, a geothermal cycle, an electrolysis unit (based on alkaline electrolyzer stack, AES), and a nanomaterial-based unit (i.e., alkaline fuel cell stack, AFC) to store hydrogen. Combining nickel nanoparticles thermally enclosed in multiwalled carbon nanotubes (MWCNTs) with a composite thermoset anion-exchange membrane enables alkaline water splitting. When the grid demands are less than generated electricity rate, additional electricity is fed into an AES to generate hydrogen fuel. Further, when the grid demands are more than generated electricity rate, stored hydrogen and oxygen are fed into an AFC to back convert the chemical energy in the fuel into electrical energy. The thermodynamic and thermo-economic evaluations of the considered hybrid process are comprehensively presented. Furthermore, multi-objective optimization of the introduced process has been developed in accordance with the genetic optimization technique to maximize the rate of electricity and minimize the cost rate. Additionally, the Long Short-Term Memory (LSTM) -based optimization technique is established and discussed. The outcomes indicated that under the LSTM-based genetic optimization technique the output electricity and electricity and hydrogen costs of the considered hybrid process can be improved by 34.55% and reduced by 40.3% and 26.8%, respectively. It was also found that the estimations obtained from the LSTM technique are very reliable, and can be relied on with acceptable accuracy. The estimation based on LSTM has an accuracy level of more than 98.1%.