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• Promising chlorine- and sulfur-based thermochemical water-splitting cycles are investigated. • Challenges related to safe and efficient thermochemical cycles are discussed in detail. • Key factors for thermodynamic, economic, and environmental evaluation are classified. • Future prospects of research and engineering activities in this field are discussed. • Different strategies to reduce energy and economic/environmental parameters are recommended. Thermochemical water-splitting (TWS) processes are regarded as one of the most environmentally friendly strategies, capable of harnessing high-temperature waste heat from industries, renewable energy, and nuclear power sources to produce clean hydrogen (H 2) on a large scale. This review investigates and discusses the thermodynamic, economic, and environmental aspects of promising TWS cycles based on chlorine and sulfur. The TWS cycles discussed in this study include copper-chlorine (Cu-Cl), magnesium-chlorine (Mg-Cl), iron-chlorine (Fe-Cl), vanadium-chlorine (V-Cl), cobalt-chlorine (Co-Cl), cerium-chlorine (Ce-Cl), hybrid sulfur (HyS), sulfur-iodide (S-I), and zinc-sulfur-iodine (Zn-S-I) cycles. Challenges associated with the safe and efficient production of H 2 using the TWS cycles, operating conditions, and potential applications are recognized and discussed in detail. The economic, safety, and environmental aspects of the TWS cycles based on different energy sources (e.g., renewable and nuclear) are thoroughly examined. Enhancing the capacity of thermochemical cycles, employing pinch analysis, and utilizing cutting-edge optimization strategies based on state-of-the-art machine learning techniques and feasible optimization frameworks to reduce energy consumption can effectively reduce the TWS-based H 2 production costs. In a short-term strategy, the primary sources of energy supply for thermochemical cycles can be provided from current nuclear power plants, waste energy from various chemical industries, and renewable energy sources. Advanced reactors and artificial geothermal energy sources can be considered to power thermochemical cycles in a long-term strategy. The outcomes of the current work demonstrate that four-stage Cu-Cl units and four-stage Mg-Cl with dry hydrochloric acid absorption cycles in chlorine-based TWS systems, and S-I and HyS cycles in sulfur-based TWS systems are promising in terms of technical viability, efficiency, economic feasibility, and environmental compatibility. The energy efficiency of the Cu-Cl, Mg-Cl, S-I, and HyS cycles are reported as 32–58.60, 30–63.63, 15.30–60, and 35–48.80%, respectively. The economically optimal cycles for H 2 production include Cu-Cl (1.28–15.56), S-I (2.25–11.65), and HyS (2.97–9.98 $/kg). The global warming potential and acidification potential for the nuclear-based Cu-Cl thermochemical cycles are categorized as 0.50–1.35 kgCO 2 eq/kgH 2 and 1.75–9.60 kgSO 2 eq/kgH 2 , respectively; they are suitable candidates for H 2 production from the environmental perspectives. [ABSTRACT FROM AUTHOR]

Brown algae adsorb a considerable amount of CO 2 and store carbon in their biomass more than many other algae species. Nowadays, depletion of fossil fuel resources, greenhouse gas emissions, climate change, and the future of human food security have encouraged scientists and policymakers to develop safer and more sustainable alternatives of energy sources. Brown algae have attracted most of this attention in North American countries to generate a wide range of products and biomass for biorefinery. In this review paper, various aspects of brown algae cultivation and its biorefinery process are discussed. Main drivers of the sectors, opportunities, challenges, and future prospects of brown algae-based biofuels in North America have been taken into account; the most appropriate processes and pathways are compared to maximize the outputs and environmental benefits, and minimize costs and drawbacks of the industry. Analysis and predictions of renewable energy future in North American countries revealed that biomass-derived fuels, including brown algae biofuels, will play an important role especially in the transportation sector. These biofuels, including bioethanol and biodiesel are accompanied by various co-products and by-products in an optimized biorefinery system to convert every available component of brown algae. However, cultivation of brown algae to produce biomass at a commercial scale with minimum costs and market demands are the main challenges of algal biofuels. Finally, expanding the value chain of the brown algae biorefinery by producing more advanced biofuels such as aviation fuels and value-added co- and by-products would significantly impact North American countries' gross domestic product. • Many studies related to biofuel production from brown algae are reviewed comprehensively. • Brown algae have attracted significant attention in North America. • Costs and markets demands are two main challenges for this algal energy. • Effective strategies for optimal production of biofuel from brown algae are provided. • Current challenges and future prospects for biofuel from brown algae are discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel system for production and storage of H 2 with net-zero carbon emissions is developed. • High-temperature fuel cells and biogas upgrading unit are efficiently integrated. • Waste heat of the fuel cells is recovered in the Cu-Cl unit for hydrogen production. • Integrated process can generate 108 kmol/h liquid hydrogen and 18.88 MW power. • A hybrid method of the GA and artificial intelligence tools is applied for optimization. Global energy consumption has been exponentially increasing, leading to the depletion of conventional energy sources and a considerable increase in greenhouse gas emissions. The exploitation of sustainable energy sources and the development of innovative methods for mitigation of CO 2 emissions is necessary. Hydrogen (H 2) as a versatile and green fuel can be produced and stored in liquid form using sustainable energy sources through innovative methods. In this paper, a novel optimal hybrid structure is proposed for hydrogen production and storage with net-zero CO 2 emissions. A high-temperature fuel cell is utilized to reduce CO 2 emissions and supply the heat and power needed to produce and liquefy hydrogen. The hybrid configuration employs an electro-thermochemical unit for hydrogen production, molten carbonate fuel cells, a hydrogen liquefaction process, and a biogas upgrading by water scrubbing. A robust combination of meta-heuristic algorithms and artificial intelligence is developed to optimize the investment return period and energy/exergy efficiencies. The fuzzy Bellman-Zadeh, LINMAP, and TOPSIS techniques are also used to make decisions in multi-objective optimization. This innovative configuration generates 108 kmol/h liquid hydrogen, 18.88 MW power, 54 kmol/h oxygen, and 3258 kmol/h hot water. Pinch, sensitivity, exergy, and economic assessments are implemented to evaluate the performance of the hybrid structure. The thermal and exergy efficiencies of the proposed configuration are obtained to be 78.21 % and 64.83 %, respectively. The greatest portions of destructed exergy are resulted from the fuel cells-gas turbine hybrid system (63.63 %), electro-thermochemical unit (25.96 %), and biogas upgrading technology (6.23 %). The returns period on investment, the prime price of electricity, and the net benefit are computed as 4.854 years, 0.0420 US$/kWh, and 15.73 million US$/years, respectively, based on the energy potentials of Newfoundland and Labrador, Canada. [ABSTRACT FROM AUTHOR]

[Display omitted] • The current status and future prospects of hydrogen production and utilization are discussed. • Challenges and government regulations for hydrogen production in North America are addressed. • High energy consumption and CO 2 emissions are the main challenges for conventional H 2 production. • Hydrogen storage materials are still lacking in both volumetric and gravimetric density. • Biohydrogen production needs further research and development before commercialization. Hydrogen is one of the most efficient and attractive energy carriers that can fulfill current and future energy requirements and address the drawbacks of conventional energy resources. Hydrogen as a fuel is nonmetallic, carbon-free, non-toxic, and has higher specific energy than gasoline (on a mass basis). Hydrogen production, storage, safety, and utilization are the four main aspects that should be considered in hydrogen energy-based systems. This review extensively analyzes the literature on fundamental, technological, and environmental aspects of various hydrogen applications and production techniques as well as theoretical and practical challenges. The global demand for hydrogen is mainly for its utilization in oil refineries (33%), chemical production (40%), metallurgical industries (3%), and the rest is in applications such as fuel, glass manufacturing, welding processes, and food industries. Natural gas, crude oil, coal, and electrolysis processes are the main feedstock sources for hydrogen production, with shares of 49, 29, 18, and 4%, respectively. Currently, hydrocarbon and alcohol reforming, gasification (coal and fossil fuels), and fossil fuel partial oxidation have the greatest shares of the hydrogen production methods. The main challenges for these methods are the high total energy consumption and carbon emissions to the environment. Water electrolysis technologies are still under development and can be combined with renewable energy resources, such as solar, geothermal, wind, and tidal to achieve eco-friendly technologies. Biohydrogen production through biological approaches such as direct and indirect biophotolysis, and photo and dark fermentation processes can be sustainable and promising technologies for bioenergy production worldwide. This review investigates the various thermochemical cycles for hydrogen production and presents the process flow diagram of each cycle. It discusses the different chemical and physical methods and materials for hydrogen storage. In fact, hydrogen storage materials are still lacking in both volumetric and gravimetric density, and in some cases, they do not have promising storage capacity. The current status of hydrogen production, available resources, various challenges in the field of hydrogen production, storage and transportation, and government regulations in North America are discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Vital parameters affecting control and utilization of co-culture systems are evaluated. • Utilization of microalgal microbial fuel cells in wastewater treatment is reviewed. • Microalgal co-cultivation systems for biomass/biofuel production are analyzed. • Techniques for biomass and lipid content measurement are comprehensively discussed. • Current challenges and future prospects in microalgal co-cultures progress are addressed. The adverse impacts of fossil fuels on the environment, specifically climate change, have intensified the need for finding a sustainable alternative source of energy. Numerous studies have postulated that biotechnology development, focusing on biofuel production processes, could be a suitable solution for sustainable energy production. The utilization of microorganisms, such as microalgae, is one of the basic strategies to produce biodiesel, pharmaceuticals, and nutraceuticals. Co-cultivation has overtaken mono-cultivation to improve the production of microalgae due to its endurance, foreseeability, and stability. However, further development of the co-cultivation process requires elaborate efforts to make it safe, practical, and optimal. Some dominant factors affecting the co-culture system control are the diversity of the cell groups, mass transfer, scale-up, population ratio, and time. In this review article, we will discuss some critical topics related to the co-cultivation process, such as data collection, modelling, cultivation methods, and interaction varieties. An overview of the quantification techniques for biomass concentration and lipid content is also provided. Moreover, the utilization of microalgal co-cultures will be analyzed, depicting the difficulties associated with their efficient control. As knowledge of the reactions and their entailing kinetics is elemental for analyzing the microalgal systems, which are used to synthesize intermediate products and chemicals, some studies focusing on the kinetics of microalgal biomass conversion into biofuels are presented. Since the microbial fuel cells (MFCs), as a new bioelectrochemical process, are utilized in the mixed-culture systems to treat wastewater and produce biofuels and other valuable by-products, a summary of the microalgal MFCs is also provided. Finally, arguments about the challenges and advantages of the co-cultivation systems are presented. [ABSTRACT FROM AUTHOR]

• Homogeneous and heterogeneous catalysts in biodiesel production are reviewed. • Transesterification reactors are used in manufacturing of biodiesel. • The impacts of key parameters on performance of transesterification process are examined. • Advantages and disadvantages of each reactor technology for biodiesel production are outlined. • Sustainability aspects of biodiesel production methods are comprehensively discussed. There is no sustainability to fossil fuels. Consequently, energy from renewable sources should meet present-day and future demand. Fossil fuel consumption has consistently influenced and harmed the environment, prompting the development of renewable and clean fuels such as biodiesel. Biodiesel production primarily involves the transesterification process, which consists of key components, namely, the feedstock, catalyst, reaction, and product separation or purification stages. It is imperative to acknowledge the emergence of innovative technologies with significant potential for biodiesel synthesis to attain a commercially viable and efficient biodiesel production process. Recently, researchers have investigated biodiesel reactors' effectiveness in energy and time efficiency in producing biodiesel. This review comprehensively assess the key technical aspects of each reactor in order to learn more about their mechanisms and pick the best reactor technology for the transesterification procedure. Various transesterification reactors, such as plug-flow, microwave, and simultaneous reaction-separation, are then examined from scientific and practical perspectives. This research aims to elucidate the merits, limitations, advantages, and disadvantages of various reactor technologies employed in biodiesel synthesis. Furthermore, it discusses the benefits, challenges, and future prospects of biodiesel. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: As concerns about rising fossil fuel prices, energy security, and climate change increase, renewable energy can play a key role in producing local, clean, and inexhaustible energy to supply Australia’s growing demand for electricity, heat, and transportation fuel. Renewable energy is an essential part of Australia’s low emissions energy mix and this energy is important to its energy security. Australia has some of the best renewable energy resources in the world. This paper will focus on the impact of these renewable energies in Australia. This study shows that Australia has the potential to secure its long term energy future through focus and encouragement on increasing utilisation of renewable energy. [Copyright &y& Elsevier]

Abstract: Hydropower is the most advanced and mature renewable energy technology and provides some level of electricity generation in many countries worldwide. As hydropower does not consume or pollute the water it uses to generate power, it leaves this vital resource available for other uses. The objective of this article is to identify and analyse issues that are imperative for hydropower energy development in Australia. This study shows opportunities for further hydroelectricity generation in Australia are offered by refurbishment and efficiency improvements at existing hydroelectricity plants, and continued growth of small-scale hydroelectricity plants connected to the grid. [Copyright &y& Elsevier]

This study aims to provide a framework which enables decision-makers and researchers to identify AI technology patterns in renewable energy systems from a massive data set of textual data. However, the study was challenged by the Scopus database limitation that allows users to retrieve only 2000 documents per query. Therefore, we developed a search engine based on the Scopus Application Programming Interface (API) that enables us to download an unlimited number of documents per query based on our desirable settings. We extracted 5661 renewable energy systems-related publications from Scopus database and leveraged Natural Language Processing (NLP) and unsupervised algorithms to identify the most frequent computational science models and dense meta-topics and investigate their evolution throughout the period 2000-2021. Our findings showed 7 meta-topics based on the class-based Term Frequency-Inverse Document Frequency (c-TD-IDF) score and term score decline graph. Emerging advanced algorithms, such as different deep learning architectures, directly impacted growing meta-topics involving problems with uncertainty and dynamic conditions. [Display omitted] • Developed a search engine to retrieve data from Scopus. • Recognized trend of AI algorithms in renewable energy systems. • Used BERTopic model to investigate main topics and their time evolution. • Identified seven meta-topics covering all dimensions of renewable energy systems. • Direct relation between advanced AI models and meta-topics with uncertain condition. [ABSTRACT FROM AUTHOR]

[Display omitted] • A comprehensive study on renewable energy resources in North America is conducted. • A detailed evaluation of renewable energy potentials is provided. • Important steps for better use of renewable energy resources are summarized. • Emerging technologies for development and management of renewable energy are addressed. • Theoretical and practical challenges in development of renewable energies are highlighted. Energy is an important drive for the economic development and social growth. The energy demand has remarkably escalated due to the technological developments in various governmental, industrial, and municipal activities. The fast growing rate of the energy demand as well as the fuel prices, along with the necessity to control the greenhouse gas emissions are the leading driving forces for effective exploitation of the renewable energy resources. In fact, satisfying the growing global energy demands and mitigating the climate change are of the utmost importance in the modern days. In this review paper, a detailed overview of the development and evolution of the renewable and sustainable energy sources is provided in terms of their types, characteristics, applications, production processes, advantages and disadvantages. Moreover, we discuss the impacts of the renewable energies on health and environment, along with the relevant policies and regulations. Further, the emerging technologies and theoretical and practical challenges in the development of the renewable energies are analyzed. Particularly, this review provides information on renewable and sustainable energies' status and prospects in North America. Central large-scale technology and distributed configurations of the renewable energies might be improved in the North American countries to effectively utilize the renewable energies for producing electricity, biomass-based fuels, and heating in both local/rural and industrial divisions. In addition to employment opportunities stemmed from manufacturing of the renewable energies, its significant impact on the economic development can be enhanced in the US, Canada, and Mexico through development of the renewable energy sources. [ABSTRACT FROM AUTHOR]