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Microbial fuel cell is a promising technology to harvest energy from wastewater, and effective anode catalysts are essential for its applications. In this study, zero-dimension nitrogen-doped carbon dots, as biocompatible efficient modifiers, were synthesized and decorated onto the carbon paper surface to prepare microbial fuel cell anode. The as-fabricated nitrogen-doped carbon dots decorated carbon paper anode was able to enhance electricity generation and efficient wastewater treatment. It was found that the as-fabricated electrode had a high hydrophilicity, which was favorable for the microbial immobilization. Compared with the carbon paper anode, the biofilm on the as-prepared anode was almost twice of thickness. After introducing nitrogen-doped carbon dots, the extracellular electron transfer process from the microorganisms to the anode was enhanced. The microbial fuel cell with the as-developed anode generated a remarkable power output of 0.32 mW, 1.1 times higher than that of the raw carbon paper anode with same measurement area. Moreover, 16 sRNA pyrosequencing analysis shows that the quantity of Pseudomonas on the electrode increased by ∼40%, which also promoted the electron transfer rate by excreting mediators like phenazines or phenazine derivatives. This work developed a new approach to design microbial fuel cell anode material and fabricate a high-efficiency and environmentally friendly anode for electricity generation from wastewater. Image 100697 • Notable power output was obtained from MFC with N-doped CDs@carbon paper electrode. • The carbon paper electrode was highly hydrophilic by decorating with N-doped CDs. • The EET efficiency was enhanced by modifying the electrode with N-doped CDs. • The relative abundance of Pseudomonas was enhanced with N-doped CDs' decoration. [ABSTRACT FROM AUTHOR]

The subsector of pulp and paper presented in 2013 an electric power consumption of 9.3% of electricity consumption in the industrial sector in Brazil. It experienced a significant growth of production in the last 20 years, exceeding 160%, and their consumption of electricity increased by 130%, reaching the level of 19,594GWh. Due to its characteristics, with a known structure and production processes, and its importance in the country's industrial sector, this subsector was selected for study in this paper, to evaluate the behavior of its long-term annual electricity demand, at the horizon of 20 years ahead, in energy efficiency scenarios through bottom-up approach. This approach is data intensive and requires data with good quality; it consists of a hierarchical structure that enables to check how specific actions can affect the results at each level and its effect on higher levels. [ABSTRACT FROM AUTHOR]

Abstract: Alarmingly low pulp prices in early 2009 left pulp and paper mills across North America desperate for any way to improve thin profit margins. One solution that continues to gain popularity among the industry is improved energy management systems for cogeneration systems, which use steam for two purposes – to provide heat for the pulping process and to generate electricity for sale to regional providers. This paper presents an energy optimization algorithm for use in a pulp and paper mill cogeneration system. The algorithm is applicable to a number of popular mill configurations, power sale contracts, and fuel purchasing scenarios. The method is also extended to address weather-dependent cooling limitations encountered by a mill cogeneration facility, in which case an iterative solution is proposed in order to maintain convexity of the optimization problem. Results are presented in the form of three case studies. [ABSTRACT FROM AUTHOR]

Abstract: The possibility of co-processing paper sludge with coal in power plants for power production and useful products was investigated as an alternative to the disposal option. The thermal behaviour of the fuels and their blend during pyrolysis and combustion processes was studied, kinetic models were developed and the compatibility of each component in the blend was evaluated. The experiments were conducted in a thermogravimetric analysis system, at non-isothermal heating conditions, over the temperature range 25–850°C. The effect of the inorganic constituents of the fuels and their mixture on thermal conversion characteristics, reactivity, slagging and fouling propensities and environmental pollution was examined. The thermochemical reactivity of the two fuels was different in both nitrogen and air. Devolatilization of paper sludge occurred earlier and with a higher rate, while its combustion was hindered by the high content of ash. When the two fuels were mixed their pyrolysis or combustion reactivities did not substantially change. A first-order parallel reactions model for pyrolysis and a power low model for combustion fitted the experimental results accurately. The kinetic parameters of the blend could be predicted from the data of the individual components. Co-firing paper sludge with subbituminous coal might somehow improve the slagging/fouling potential of the coal. However, if the mineral matter of paper sludge is partly removed before use, then the combustion behaviour of the mixture could resemble that of coal alone and the overall efficiency of the process would increase. [Copyright &y& Elsevier]

[Display omitted] • Various carbon nanotube-based devices are developed for solar energy utilization. • The water evaporation system can generate freshwater (1.28 kg m−2h−1). • The solar-thermoelectric system can output a voltage and charge a cellphone. • The supercapacitor performs an areal specific capacitance of 19.6 mF cm−2. • The hybrid energy system can produce freshwater, generate and store electric power. Nowadays, multi-functional systems driven by solar energy have been explored to alleviate the crisis of energy and freshwater scarcity. However, it remains a great challenge to integrate multi-functions into one hybrid system with a monolithic material, which can harvest, convert and store solar energy synergistically. Here, we firstly propose a multi-functional carbon nanotube paper, which starts from a material level to solve these problems. The carbon nanotube paper is fabricated by vacuum filtration. It exhibits high efficiency of solar-thermal conversion. Secondly, three types of energy conversion/storage systems (e.g., solar-thermal evaporation system, solar-thermoelectric generation system, and supercapacitor) are constructed based on the carbon nanotube paper, which extend the research to a device level. The solar-thermal evaporation system shows an evaporation rate of 1.28 kg m-2h−1 under simulated sunlight irradiation of 1 kW m−2. The solar-thermoelectric generation system demonstrates a stable electric power generation with an output voltage of 100 mV under light irradiation of 1 kW m−2. The supercapacitors perform the energy storage function with an areal specific capacitance of 19.6 mF cm−2. These devices and systems can be used in freshwater generation (0.84 kg m-2h−1, sunlight irradiation of 1 kW m−2), water purification/desalination (inorganic ions rejection larger than 99.9%) and portable solar charging system (maximum output voltage of 5 V). Finally, a hybrid energy system is innovatively proposed from the system level to simultaneously produce freshwater, generate and store electric power. Through the synergetic coupling of solar conversion and storage technologies, the hybrid energy system can supply sustainable freshwater and electricity for remote areas in daily life, highlighting the superiority of multi-energy (thermal energy, electrical energy, and electrochemical energy) complementary. [ABSTRACT FROM AUTHOR]

Highlights • We develop a novel portable and disposable paper-based biobattery. • Our biobattery is on-demand electricity generation activated by a drop of tap water. • A low-cost, simple-structure battery case is created by single layer of paper filter. • We proposed integrated air-cathode paper-based proton exchange membrane. • Proposed battery can be used for paper-based diagnostic devices. Abstract A novel, portable, and disposable paper-based microbial fuel cells (MFC) generating electricity from harmless strain of Escherichia coli (E. coli) has been developed. This MFC is on-demand electricity generation activated by a drop of tap water in a dry anode containing the biofilm of E. coli. A low-cost, simple-structure MFC case was created by a single layer of paper filter with high order of folding, which could support interchangeable dry bacteria-loaded anodes. The paper filter was innovatively engineered to make an integrated air-cathode proton exchange membrane (ACPEM) by coating carbon nanotube mixed with potassium ferricyanide on one surface and spraying hydrophobic solution on the other surface, respectively. The E. coli biofilm pre-inoculated in the anodes made of activated carbon sheet was simply dried in the air for the sake of long-term storage and usage. The dry anodes can be simply set in the MFC case with the readily prepared ACPEM, which can be used for on-demand power generation within seconds after adding water with maximum power density of 8.8μW/cm2. [ABSTRACT FROM AUTHOR]

Abstract: Gold is among the highly conductive and stable materials, which are ideal anodes for microbial fuel cells (MFCs). However, previous studies have shown that bare gold surface is recalcitrant for the colonization of some exoelectrogens, e.g., Shewanella putrefacians. In this work, the problem regarding the poor bio-compatibility of gold as an anode material was sorted out through coupling it with carbon paper. A new composite anode material was fabricated through sputtering gold layer homogeneously on carbon paper matrix. Results of cyclic voltammetry and electrochemical impedance spectroscopy in Fe(CN)6 3−/4− solution demonstrated better electrochemical performance of the carbon paper–gold (C–Au) composite than either carbon paper or bare gold, when they were used in MFCs. With Shewanella oneidensis MR-1 as the inoculum, the C–Au anode-based MFC produced total electric charges higher than the carbon-paper-anode-based MFC by 47%. The cyclic voltammetry analysis and the scanning electron microscopy observation showed that the MR-1 biofilm growth was accelerated when the carbon paper surface was sputtered with gold. Utilization of such a carbon paper–gold composite significantly enhanced the MFC performance. [ABSTRACT FROM AUTHOR]

Abstract: Integration of biomass gasification with a pulp and paper mill is a possible route to create more value-added products. This route facilitates, for example, more advanced electricity generation and production of biomass based transportation fuels or chemical feedstock. Each unit operation in such a process affects overall efficiency as well as possibilities for process integration. In this paper, the impact of different dryer types in a biomass gasification combined cycle (BIGCC) has been evaluated in terms of efficiency and economic performance. The BIGCC was sized so that the excess heat would replace the current steam production from bark and oil. The results show that the dryer type can have a significant impact on economic performance and efficiencies. A BIGCC with an integrated belt dryer, utilizing excess heat to heat the drying air from the mill, can result in electrical efficiencies of up to around 40%, while e.g. a steam dryer can reach 36–37%. Choice of oxidant, air or oxygen, in the gasifier affects both capital and operational cost. Air was proven to be the most cost efficient solution for the cases evaluated in this study. The investment of around 100 to 140 million Euros for a BIGCC facility is profitable for most evaluated cases for an annuity factor of 0.1, while the net annual profit is negative for most cases when the annuity factor was increased to 0.2, even when including financial support for renewable electricity. [Copyright &y& Elsevier]

An enormous gap exists between Africa's current electrification rate and the 2030 UN goal to ensure universal access to modern energy. A study by Sanoh et al. published in Renewable Energy in 2014 [1] is a rare example of finding a cost minimal solution for the Africa-wide generation and transmission network. Unfortunately, however, the paper exhibits a number of relatively serious flaws that demand attention given the alarming paucity of such research on Africa. Five issues of the study by Sanoh et al. are identified and discussed in this commentary paper. Specifically, the study does not account for capacity factors when deriving required capacity additions, misses transmission losses when sizing generation capacity, models country-level import constraints incorrectly, introduces a supply option redundancy, and reports optimisation results that can be shown to be mathematically sub-optimal. As a result of some of these issues, the Sanoh et al. significantly underreport the required capacity to meet additional African demand in 2025. In addition to discussing these flaws, this paper provides potential approaches to avoid each of the five issues. [ABSTRACT FROM AUTHOR]

We reported a novel, non-optical technique to analyse and quantify the transportation of bacterial cells in paper-based microfluidics. This approach was based on real-time measurement of the microbial electricity production. Our device was designed to have three hydrophilic regions linked by a channel on a paper layer by patterning hydrophobic barriers in the paper. Each region came into contact with an anodic electrode layer which was stacked with a cathodic compartment through a proton exchange membrane. When bacterial cells were transported to each region by capillary force, the bacteria cells were promoted to adhere onto the anode and the cells completed their respiration by transferring the electrons to the anode. A conductive load connected the anode and cathode to complete the external circuit through which the electrons flowed. The protons generated by the anodic reactions passed through the proton exchange membrane and travelled to the cathode, where they combined with electrons in the reduction process. By measuring the current through the load, bacterial cells’ transportation through the channels in paper was quantitatively investigated according to the pore size of the paper. Further understanding was made by analysing electron microscope examination of the hydrophilic regions. This work will determine more efficient cell movement within a paper material by controlling the paper's microfluidic dimensions and pore size. It will also provide a quantitative understanding of the flow of large organisms for use in paper-based diagnostics. [ABSTRACT FROM AUTHOR]

Using a discounted cash flow methodology, we have performed a detailed analysis of the current costs of electricity from two Indian nuclear reactors. We compare these costs to that from a recently constructed coal-based thermal power plant of similar size. Our results show that for realistic values of the discount rate, electricity from coal-based thermal power stations is cheaper than nuclear energy. [Copyright &y& Elsevier]

Abstract: A new tar destruction technology has been developed by integrating in-situ catalytic gasification and a hot-gas cleaning system in the catalytic gasification of paper-reject sludge. Experimental results indicated that the tar yield in syngas decreased significantly from 13.64 to 10.76 g/m3, when increasing the zeolite addition during in-situ catalytic gasification. When the syngas passed through the hot-gas cleaning system, the tar concentration measured from downstream was approximately 0.22 g/m3. The hot-gas cleaning system used in this research seems to have played a significant role in reducing tar concentration of the syngas. The major tar speciation identified after hot-gas cleaning system was 1-ring or 2-ring hydrocarbons, which included benzene, toluene, xylene, styrene and naphthalene. In summary, the energy yield efficiency of syngas will be enhanced due to the tar reduction and transformation. The syngas seems to be appropriate to use as a fuel in gas engines for electricity generation. [Copyright &y& Elsevier]

Abstract: The all-China-made proton exchange membrane fuel cell units were created and one fuel cell stack was assembled, with all domestic material such like Chinese proton exchange membrane, Chinese catalyst, Chinese carbon paper and Chinese graphite plate, on the basis of heat shaping CCM technology and modularized fuel cell stack assembly technology. The fuel cell unit was tested and optimized. The electricity generating test and other related experiments were conducted. It’s showed that the fuel cell unit’s performance was stable and its power density could reach 550 mW/cm2; the fuel cell stack’s operating power had reached 200 mW/cm2 with voltage uniformly distributed. The stack was stable and showed no obvious decrease in performance after 1800 h continuous operation. Discharged water analysis showed the all-China-made fuel cell stack’s materials had good chemical stability. This new type of fuel cell stack is much cheaper in production cost, compared to the same level import fuel cell stack. [Copyright &y& Elsevier]

The collection of sawmill residues is an important logistic activity for the pulp and paper industry, which uses the biomass as a source of energy. We study a vehicle routing problem for a network composed of a single depot and several sawmills. The sawmills serve as potential suppliers of biomass residues to the depot, which in turn processes and distributes the residues to the pulp and paper mills. This problem consists of identifying the best daily routing schedule for a fixed number of trucks. The objective is to maximize the ratio of energy returned on energy invested, while satisfying a minimum daily amount of dried biomass residues. There are several random components in the problem, including the availability and moisture content of the biomass residues. We use a combination of scenario analysis and heuristics to solve this stochastic vehicle routing problem. A performance comparison of the proposed method reveals an estimated daily energy savings of 6 GJ over the benchmark method. [ABSTRACT FROM AUTHOR]

The use of fuel cell (FC) is considered one of the methods of producing electricity with relatively high efficiency. So, it has attracted many researchers' attention to develop and improve its performance. The present study deals with the technical-economic optimal design of a hybrid power generation system based on a Proton Exchange Membrane (PEM) FC combined with an Organic Rankine Cycle (ORC). ORC is used to recover the generated heat in PEM FC. The decision variables of this study include FC operating pressure and temperature, current density, FC area, the quantity of FC, and operating parameters of the ORC system, including HRVG PPTD, condenser PPTD, and refrigerant mass fraction in zeotropic mixture. In this study, three zeotropic mixtures, including R11-R245fa, R11-R123, and R123-R245fa, are studied as the working fluid of the ORC system. The objective functions considered to be optimized are the system's exergy efficiency and total cost rate (TCR). Finally, it is observed that the highest exergy efficiency is obtained using the zeotropic mixture R11-R245fa with a value of 54.15%, and the lowest TCR is obtained with the mixture R11-R123 with a value of 0.65 $/s. Zeotropic mixture R11-R123 has the exergoenvironmental index, environmental damage effectiveness index, and exergy stability factor of 0.5506, 1.277, and 0.4750, respectively. • A hybrid electricity generation system including PEM FC and ORC is analyzed. • Exergy Efficiency and economic analysis are considered for system evaluation. • Three novel zeotropic mixtures are examined as the working fluid of the ORC system. • A Parametric Study and optimization are conducted in this research paper. [ABSTRACT FROM AUTHOR]

This paper has sorted out the general logic of the impact of COVID-19 on energy consumption. In the short term, the epidemic has forced governments to adopt different levels of lockdown measures. The total electricity consumption decreased and the share of renewable energy has increased. Based on the International Energy Agency's (IEA) data on electricity production and consumption, this paper analyzes the long-term effects: The COVID-19 pandemic does affect overall electricity demand and market structure in the short term, but in the long term, the impact of the pandemic is detrimental to the proportion of electricity generated from renewable sources. Increased, especially in hard-hit countries. The impact on countries with different levels of development is different, and countries with higher levels of economic development are better able to resist such exogenous shocks. The pandemic is still ongoing, how to steadily promote sustainable development? In this paper we suggest that to cope with climate change, to accomplish energy transformation and upgrading or even sustainable development, we should not only rely on reducing human activities, but give more support to countries with low development levels in realizing sustainable development. [ABSTRACT FROM AUTHOR]

Abstract: This paper provides analysis of the availability of grain straw resources for centralised industrial usages and suitable areas in China at the prefectural level. China has abundant straw resources for both decentralised and centralised usages. Decentralised usages are inefficient and cannot absorb enough straw. However, centralised usages have technological and economic problems, such as product cost and resource supply, and therefore, a system analysis of the economic available resources and suitable areas are needed. Three main grain crops – rice, wheat, and corn – and three typical centralised usages – paper making, direct combustion power generation, and bioethanol – are investigated in this study. An optimal model is established on the basis of straw resource characteristics and techno-economic characteristics of the usages and used to calculate the distribution of suitable prefectures and the largest supply of resources for each usage. The study focuses on prefectures in 13 provinces with relatively abundant grain straw resources. The suitable areas for paper making are in North China, for direct combustion power generation are in North and Northeast China, for bioethanol are in Northeast China. The largest economic available resources for paper making, direct combustion power generation, and bioethanol are 47.5, 221.4, and 164.4 million tons, respectively. The operation cost and the ratio of straw actually collected from production are selected for conducting a sensitivity analysis. The impacts of other factors, including the geographical environment, local product demand, existing industry, change in total straw production, technical progress and straw from other crops, are discussed. [Copyright &y& Elsevier]

To facilitate a successful integration of distributed energy resources into the electricity generation mix, new forms of energy markets must be considered. Concepts such as Peer-to-peer energy trading (P2P), transactive energy (TE) and community/collective self-consumption (CSC) are frequently mentioned as solutions to this challenge. Despite increasing interest from industry, policy, and academia, the field lacks a shared understanding of this class of models. This need is addressed by presenting sets of shared and distinct characteristics which define P2P, TE and CSC. Our analysis is based on a series of expert group interviews with regulators, industry, and academics across 13 countries, and a systematic and targeted literature review of 133 papers. Findings show that P2P/TE/CSC models can be described as sub-markets that operate within or alongside traditional energy markets and enable trading or sharing of energy using an automated approach. They focus on promoting and supporting local energy generation and consumption using price negotiation mechanisms that reflect the aims of the market. The paper also presents sets of characteristics which differentiate P2P, TE, and CSC from one another and sets out guiding definitions to be used as a reference point. The main differences between these models stem from the goal they are trying to achieve and the contexts they are deployed in. Findings from this analysis can support development of a shared understanding of this class of models across multiple disciplinary perspectives and applications. • Decentralised energy trading models lack a unified definition. • Expert interviews and literature review identify defining characteristics. • Decentralised models can operate as sub-markets alongside traditional markets. • Distinctions between models stem from their goal and the contexts they are deployed in. [ABSTRACT FROM AUTHOR]

The optimal capacity configuration of combined wind-storage systems (CWSSs) serves as a foundation and premise for building new electricity system. This paper proposes a novel capacity configuration model of CWSS. The model simultaneously considers economy, stability and low carbon by respectively minimizing Levelized cost of electricity (LCOE) and maximizing effective load carrying capacity (ELCC). The multi-objective optimization model is solved by Non-dominated Sorting Genetic Algorithm II (NSGA-II). And Multi-Attributive Border Approximation Area Comparison (MABAC) method is used to score the alternative solutions on the Pareto front and make decisions under different scenarios. The results of the case study show that: (1) The evaluation of the ELCC for CWSS can quantify its ability to replace the installed capacity of thermal power, thus greatly reducing the uncertainty of wind power output. (2) Under low-carbon scenario, economic scenario and standard scenario, the results of optimal capacity configuration for the CWSS show that LCOE and ELCC are negatively correlated. When the weights of ELCC and LCOE are equal, the three goals of economy, low carbon and safety and stability are achieved. (3) The results of a single sensitivity analysis on LCOE show that the sensitivity coefficient of electricity generation is the highest, exerting the greatest impact on the capacity configuration decision of the CWSS. A 20 % increase in power generation can reduce LCOE by 0.1203RMB/kWh. This paper provides energy planning recommendations for decision-makers in CWSSs, contributing to the development of a reliable new electricity system. • A multi-objective optimization of CWSSs considering ELCC and LCOE. • Multi-objective optimization model is established based on NSGA-II and MABAC. • The model of LCOE based on ELCC is proposed. • The model is presented to achieve the optimal capacity configuration of the CWSS. [ABSTRACT FROM AUTHOR]

Load-following capability is one of the distinguishing features between Small Modular Reactors (SMRs) and traditional large-scale reactors in existing nuclear power plants. An SMR needs to possess load-following capability to integrate with non-dispatchable energy resources, e.g., renewable ones, to form an off-grid hybrid energy system. This paper provides a comprehensive review of different aspects of load-following operations of nuclear reactors by systemically examining early studies and some practical operating experience on existing nuclear reactors in various applications. These applications include electricity generation, marine vessel and spacecraft propulsion, and heat generation for industry applications. Considering different advanced reactor design concepts proposed for SMRs, the paper has concentrated on six representative reactor types and highlighted their unique features and feasibilities for load-following operations. Since an SMR can be considered as a combination of the reactor and the balance-of-the-plant, its power output can be regulated at the reactor power output or from the balance-of-the-plant. Different techniques to implement load-following operations have been described regarding different reactor designs and compositions of the balance-of-the-plant. Several special issues deserve special attention when performing load-following operations. These issues are rarely encountered in existing nuclear power plants for base-load operation, for example, imbalance in core power distribution, flow-induced vibration, excessive production, higher risk of fission products leaking, and flow-accelerated corrosion. The paper has provided necessary coverage of these less obvious consequences associated with load-following operations. • The load-following capabilities of an SMR is vital for off-grid power, marine, and space applications. • The choice of coolant and the reactor design can affect load-following characteristics. • Direct load-following techniques are constrained by physical limits of components. • Indirect load-following techniques can soften the stress on the reactor. • The load-following can exert stress on SMR components adversely. [ABSTRACT FROM AUTHOR]

Abstract: To evaluate a suitable electrode material for the efficient green energy generation of a bio-fuel cell, carbonaceous based carbon cloth, carbon paper, and carbon felt electrodes were investigated under different mediators. The larger surface area, low resistance, and open network of interwoven fibers of the carbon felt electrode facilitated higher electron transfer from the microbial organisms to the electrode surface than that of other carbonaceous electrodes. Carbon paper electrode exhibited lower fuel cell performances due to its lower roughness and high tortuous nature. The green power generation experiments were also carried out under different mediators such as 2-hydroxy-l,4-naphthoquinone and thionin. The electrons mitigation and power generation was augmented by 2-hydroxy-l,4-naphthoquinone than thionin due to its high solubility, stability, and minimal adsorption characteristic to the electrodes. By the combined efforts of extended electrons generation and transportation, bio-fuel cell performances were extended and endorsed its doable applications in bio-fuel cells. [Copyright &y& Elsevier]

• Phasing out coal-fired power is inevitable, but a deeply complex process from a social-institutional standpoint. • The nature of the coal-fired power transition is comparable to the automotive industry closures observed in Australia's recent industrial past. • This paper draws on just transitions and the transition management analytical frameworks. • Four key insights offer pointers for policymakers to support the transition away from coal-fired power in Australia and globally. Nearly three-quarters of Australia's electricity generation is coal-dependent with fossil fuel-led electricity contributing to over a third of Australia's CO 2 emissions. Climate change imperatives are calling for permanent shifts to these patterns, leading to early closure announcements of several coal-fired power plants across the country. Although the pace and scale of the energy transition are unprecedented, the closure of large-scale industries is not uncommon. The most recent closure in Australia's industrial past that remains vivid in the nation's collective memory was the end of nearly 70 years of automotive manufacturing. Drawing on expert consultations, and applying just transitions and transition management thinking, this paper identifies four key insights from the auto sector closure experience. These offer compelling pointers to guide socio-economic transformations in frontline regions that are likely to face challenging, often deeply personal, impacts resulting from the closure of coal-fired power stations over the coming decades. [ABSTRACT FROM AUTHOR]

The challenge of global warming requires deep decarbonization of the electricity system, which can be achieved with a higher share of renewables in the electricity mix. However, the driving mechanism for renewable penetration in electricity production has not been clearly revealed so far. Using the data of the European Union (EU) during 2001–2017, this paper aims to investigate the spatial-temporal heterogeneity and dynamic evolution mechanism of renewable electricity penetration. To this end, from the investment-production-consumption perspective, renewable electricity generation is decomposed into seven factors through temporal and spatial factor decomposition methods. Then, this paper integrates the factor decomposition results into a coupling elasticity analysis to study the dynamic evolution mechanism of renewable penetration in electricity production. The results are as follows. (1) Investment structure contributes the most to increasing renewable electricity generation, while the energy intensity effect and renewable generation-to-capacity ratio effect are the main reasons for the reduction in renewable electricity generation. The effect of technological structure is minor. (2) The economic scale effect and the investment structure effect are dominating factors accounting for the regional difference of renewable power generation between the EU countries and the benchmark region. (3) The progress of renewable electricity penetration accelerates over time for the EU, western EU, and eastern EU. The Western EU has realized remarkable progress in facilitating renewable electricity penetration during 2009–2017. (4) On the whole, the investment effect makes the largest contribution to promoting renewable electricity penetration, while the production effect is the major inhibiting factor, showing that there is considerable potential in renewable generation efficiency improvement in the EU. This paper provides insightful implications for energy policies aimed at the shift towards a low-carbon electricity system in the EU, which also gives a reference for other economies. [ABSTRACT FROM AUTHOR]

Nuclear hydrogen production is experiencing an unprecedented momentum worldwide, in response to the increasing demand for clean large-scale hydrogen production in line with the outcomes of the UN Conference of the Parties (COP26). A seamless integration of several innovative nuclear designs including Small Modular Reactors with steam Rankine cycle and the cogeneration of Hydrogen using thermochemical water-splitting cycles (e.g., the Cu–Cl cycle) is possible for a complete solution of hydrogen, oxygen, and electric power generation. In this paper, a process and flow sheet for large-scale hydrogen production by CuCl electrolysis at 50 tonnes per day is proposed and analyzed. The scaled-up process and flow sheet is based on lab-scale experience with 50 l/h hydrogen generation. Pressurized Cu–Cl electrolysis and basic electrolysis are reported to support the scaling up parameters, assumptions, and considerations. Based on determined sizing parameters and energy analysis, the Cu–Cl cycle consumes substantially less primary energy (thermal) than water electrolysis, which makes it a serious competitor, despite its obvious higher investment cost in the hardware. • Flow sheet for large scale hydrogen production by CuCl electrolysis is analyzed. • Consideration of pressurized Cu–Cl electrolysis is discussed and analyzed. • Cu–Cl cycle consumes substantially less primary energy than water electrolysis. [ABSTRACT FROM AUTHOR]

Steam is an important medium for energy transmission in industrial parks. For providing steam to multiple users, it is key to determine the optimal number of steam levels in the design of steam system. With the increasing number of steam levels, the energy demand and supply can be better matched but the investment of steam pipeline network increases. In this paper, this trade-off is solved by a two-stage method. In the first step, a mixed-integer nonlinear programming (MINLP) model is established to minimize the total cost of the steam system of the industrial park, while a simple pipeline network optimization model is involved. The optimal scheme of steam production including the number of steam levels can be obtained automatically. In the second step, GeoSteiner algorithm is used for solving Rectilinear Steiner Minimum Tree (RSMT) model to further optimize the pipeline network separately. In a case study, the optimal number of steam levels is 3. The total annual cost (TAC) of the optimal steam system is 11.4%, 5.28%, and 1.43% lower than the schemes with the lowest pipeline network cost (1 level of steam), the best matching between heat supply and heat demand (6 levels of steam), and the largest electricity generation capacity (4 levels of steam), respectively. The sensitivity analysis indicates that the overall heat load required by consumers and the distance between the energy station and consumers can make a difference to the optimal number of steam levels. • Steam production and steam supply in industrial park are optimized simultaneously. • Trade-off between electricity generation and pipeline cost is considered. • Effects of the load and distance of consumers and economic parameters are discussed. [ABSTRACT FROM AUTHOR]

The electric power industry is related to the national livelihood, and regional economic development is closely related to the pillar industry. At present, China's economy continues to develop steadily, and the promotion of domestic industrialization has also increased the demand for electricity. In recent years, the state power industry has made great progress, in order to further adapt to the needs of domestic and foreign market competition, the State Grid has also carried out a systematic reform of its own management system. In the reform process, strengthening the construction of performance appraisal system is a very important change. According to statistics, as of June 2020, the number of employees of State Grid has reached more than 900,000. As the most basic business unit of the state grid, the team is the cell of the state grid. It is the basis for the completion of various production management work and plays an important role in the safe production and stable output of electric power enterprises. Based on the relevant indicators of the work of the team, this paper analyzes the performance of the team through the production cost performance model, and provides suggestions for the optimization of the team for power grid enterprises [ABSTRACT FROM AUTHOR]

• A membrane-less μPFC with dual photoelectrodes and lateral design is developed. • Photoanode is formed by coating CdS/ZnS-TiO 2 on the FTO conductive glass. • Air-breathing photocathode is formed by coating CuO on porous carbon paper. • Both the photoanode and photocathode show the visible-light response. • The developed μPFC exhibits good discharging and long-term performance. Photocatalytic fuel cell (PFC) is a promising wastewater treatment technology, which cannot only purify wastewater but also generate electricity using solar energy. In this study, a membrane-less visible-light responsive micro PFC was developed, where the CdS/ZnS-TiO 2 deposited on a conductive glass as a photoanode and CuO deposited on the porous carbon paper as an air-breathing photocathode were laterally arranged. Such design allows for both the photoanode and photocathode to be irradiated simultaneously from one side and enhances photon and mass transport. It was found that the developed micro PFC with dual photoelectrodes well responded to light illumination and exhibited good long-term performance. Experimental results also showed that upgrading the light intensity and methanol and electrolyte concentrations could improve the discharging performance because of larger amount of generated electron-hole pairs and more hole scavengers resulting from the enhanced transport. Besides, it was also found that although the increase of the liquid flow rate from extremely low rate to a moderate one caused the residence time to be lowered, positive contribution resulting from enhanced mass transport was more significant, leading to the improved performance. However, too high liquid flow rate resulted in critical low residence time, which made the discharging performance worse. The feasibility of the developed micro PFC with dual photoelectrodes toward the applications of using solar energy to remove organic pollutants contained in wastewater and simultaneously generate electricity is demonstrated in this work. [ABSTRACT FROM AUTHOR]

At present, energy represents a key element in the social and economic development of a territory. This is particularly true for fragile territories that are not interconnected, such as small island states. As is true for many of the Small Island Developing States (SIDS) worldwide, the energy situation of the Comoros is substantially based on fossil fuel imports. The socioeconomic development of this archipelago is overwhelmingly dependent on energy security from sustainability, availability and affordability perspectives. As a forward-looking response to energy vulnerability, the deployment of renewables to diversify the generation of electricity appears to be an essential prerequisite for guaranteeing a sustainable future. Nevertheless, despite a high potential for renewable energy, only 3.8% of the electricity supply in the Comoros is provided by hydropower. This paper provides a comprehensive overview of the energy situation throughout the Comoros and focuses on renewable energy opportunities to facilitate the supply of green power. This study ultimately shows that renewable energies are rarely exploited despite the powerful potential of different resources. Finally, this paper attempts to provide recommendations for the Comoros to pursue a more sustainable future. • Analysis of the current energy situation of Comoros. • Defining renewable potential and ongoing actions. • Analysis of the specific barriers and policy to the development of RES in the Comoros. [ABSTRACT FROM AUTHOR]

This paper presents an overview of current electricity generation and consumption patterns in the Arctic. Based on published data and new data collection this paper provides an overview of the installed capacity per energy source. A more detailed view of electricity systems is also presented, showing how different types of resources can be used and combined within Arctic communities. The paper briefly discusses which aspects of transmission systems are of special interest under the harsh climatic conditions of the Arctic. A description is given of the various electricity generation technologies that have been proven to be effective for use in Arctic environment, and those that are currently in use, including diesel, hydropower, photovoltaic, and wind power, in addition to discussion of different back-up options. Furthermore, for a more holistic view concerning such energy systems the socio-economic dimension is addressed with a focus on energy security, through an investigation of energy availability and affordability in the Arctic. The availability of energy in the harsh Arctic environments can be crucial for survival and affordability, and can have a huge impact among low-income communities. • Overview of current electricity generation and consumption patterns in the Arctic. • Potential use of different energy resources in the Arctic. • Arctic Energy security. • Socio-economic dimension of energy systems in the Arctic. [ABSTRACT FROM AUTHOR]

Real-time hybrid simulation (RTHS) divides a structural system into an analytical and experimental substructure. The former is based on a well-established analytical model while the latter consists of a physical model in the laboratory, for which there is not a well-established analytical model. This paper extends real-time hybrid simulation to monopile-type Offshore Wind Turbines (OWTs) to enable the investigation of their behavior considering the response of pile foundations under operational and more severe conditions. The embedded foundation and surrounding soil of the OWT are modeled physically in a soil box in the laboratory while the remaining parts of the system and loading are modeled analytically. The program OpenFAST, developed by the National Renewable Energy Laboratory (NREL), is linked to the RTHS coordinator to determine the hydrodynamic and aerodynamic loads acting on the OWT, along with modeling the dynamics of the electric power generation equipment and associated controller for the OWT. The RTHS framework along with its initial implementation and validation are described in this paper. RTHSs of a 5 MW OWT subjected to operational and more severe conditions are performed to experimentally validate the framework. The framework offers a realistic approach to investigate the behavior of OWT structures supported on monopiles. This approach accounts for the coupled response of the OWT structure with its foundation, while experimentally capturing the nonlinearities of the soil-foundation interaction in real-time. • RTHS is extended to offshore wind turbine monopile structures. • OpenFAST software is modified and integrated into a RTHS framework. • Validated RTHS framework that incorporates the complete system into the simulation. • RTHS enables experimental assessment of offshore wind turbine foundation behavior. • RTHS computational challenges of offshore wind turbine structures are presented. [ABSTRACT FROM AUTHOR]

This paper explores the integration of microgrids with wind turbines to optimize electricity generation and enhance dispatch to distribution networks. The focus lies on a comprehensive examination of the microgrid configuration linked to a wind turbine, encompassing aspects such as the wind power generation system, variable-speed wind energy determination, fault estimation for stability analysis, and control through fault detection. Microgrid instability during network faults, attributed to limited capacity, is a primary challenge addressed in this study. The use of electronic interface power in islanded mode encounters hurdles due to the insufficient capacity of dispersed generation sources, leading to a slow response to load changes and difficulty in maintaining stability. To address these challenges, a novel microgrid topology and control method are introduced, featuring the integration of a battery to mitigate the slow response of micro-sources to load changes. Additionally, the concept of droop control is elucidated to effectively balance generation and consumption in islanded mode. The proposed approach employs fuzzy logic control systems along with a developed Kalman filter to precisely identify fault areas for stability analysis. Simulation results presented in this paper showcase substantial improvements in fault estimation, stability analysis, and various evaluation criteria. The abstract concludes by highlighting the keywords relevant to the study, emphasizing the significance of microgrids, energy storage systems, power converters, droop control, multiple control, and dynamic stability. In summary, this paper contributes to the discourse on renewable energy systems by presenting a comprehensive investigation into the integration of microgrids with wind turbines, offering valuable insights into improving stability, fault detection, and overall performance. [ABSTRACT FROM AUTHOR]

Meeting energy demands necessitates the initial focus on hydrogen generation, followed by prioritizing hydrogen storage and transportation. Hydrogen generation can be categorized into on-site and off-site methods. Opting for on-site hydrogen generation is preferable when powering fuel cells for electricity generation, as it eliminates the costs associated with storage and transportation. Nevertheless, certain off-site hydrogen production techniques coupled with storage and transportation are more cost-effective than some on-site generation approaches. In this review paper, diverse hydrogen production methods (both on-site and off-site) are explored, involving a range of chemical compounds such as composite materials, various photosynthetic bacteria, different electrolysis approaches for water, aluminum-assisted hydrolysis, and steam reforming of methane and methanol. The paper offers a thorough examination of the hydrogen generation method within its peer group, leading to conclusions that are drawn from their potential exergo-economic implications. Furthermore, the viability of different methods for generating hydrogen, particularly in the context of fuel cell applications, is indicated. [Display omitted] [ABSTRACT FROM AUTHOR]

The paper introduces a robust methodology for evaluating complex electricity system efficiency, making several contributions. It systematically decomposes the electric power system into various processes, including power generation, transmission, distribution, and power consumption, with parallel sub-processes for production and domestic power consumption. Employing data envelopment analysis (DEA), the paper develops a network directional slacks-based (DSB) model to evaluate the whole system and the internal processes. The model is theoretically proven to be feasible, providing efficiency scores and identifying inefficiencies in the system and its processes. A noteworthy addition is the introduction of the DSB green Luenberger productivity index and its decomposition, offering an analysis of productivity changes in electricity systems. Empirical analysis covering 30 Chinese provinces from 2013 to 2019 uncovers the performance variations among provinces and processes, pointing out inefficiencies and changes in technology and efficiency over time. The empirical findings aim to support efforts in enhancing the overall efficiency of China's interprovincial power system. • We decompose the complex electric power system into four processes with dependence. • We build a network directional slacks-based (DSB) model for the complex power system. • We give a DSB green Luenberger productivity index (DPI) for our network model. • The efficiency score and DPI of the system are decomposed into those of processes. • We apply the model and indexes to electric power systems in Chinese provinces. [ABSTRACT FROM AUTHOR]

• An improved model DWTimesNet based on dilated convolution and WN is proposed. • RF was used to reduce the effect of missing data on the proposed model. • To eliminate the effect of some variables, MIC is used for feature selection. • The PBT algorithm is used to efficiently parameterize the proposed model. • Two cases with different data quality are used to verify the proposed model. The share of wind power in global electricity generation is increasing year by year, and the prediction of wind power is a practical and necessary scientific research. In this paper, the TimesNet model is used for multistep prediction of wind power. It is observed that the prediction error of the TimesNet model could be improved by replacing the original convolutional structure with the dilated convolution and weight normalization (WN). And in addition, the population-based training (PBT) algorithm is introduced to guide the model tuning. Missing values in the raw data are imputed to enhance data integrity. And the maximal information coefficient (MIC) method is chosen to select features for the different influences on wind power, which reduces the computational effort of the model. In order to demonstrate the effectiveness of the proposed model MIC-PBT-DWTimesNet, nine models are arranged in this paper as a control group and compared with their predicted values with each other. It can be observed that the RMSE of the proposed model MIC-PBT-DWTimesNet is decreased by 17–33% compared to the base TimesNet method. [ABSTRACT FROM AUTHOR]

Decentralised grid-connected photovoltaic systems (DGCPS) have proved to be an alternative to traditional electricity generation because they have introduced advantages to power systems, such as reducing electrical losses, relieving transmission and distribution lines, and provisioning ancillary services. Despite all these benefits, a new class of problem concerning DGCPS has been reported in the literature. From the utilities' point of view, the installation of a DGCPS may lead to an apparent degradation of the load power factor. This effect does not have physical causes, i.e. equipment malfunction or overuse of reactive power by the load, although it may lead to reactive power excess charging (RPEC). Since these charges could lengthen the payback of PV installations, this paper aims to assess three strategies to tackle this issue. The first strategy, which has demonstrated to be best for prosumers, is a new regulatory scheme for reactive power monitoring in consumer units with DGCPS. The other two solutions are classical approaches based on reactive power compensation from PV inverters or capacitor banks. For these two last solutions, this paper provides an innovative and optimized way of operation that can adjust the load power factor measured by the utility in real-time, minimizing economic losses. Image 1 • We tackle the apparent degradation of the power factor that is caused by PV systems. • The proposed solutions can avoid reactive power excess charges for PV owners. • We got an ideal power factor for PV inverters to minimize active power curtailments. • PV systems can reduce the apparent power in the grid and reduce electrical losses. [ABSTRACT FROM AUTHOR]

Short-term forecasting of electricity generation from variable renewable energy sources is not an end in itself but should provide some net benefit to its user. In the case of electricity trading, which is in the focus of this paper, the benefit can be quantified in terms of an improved economic outcome. Although some effort has been made to evaluate and to improve the profitability of electricity forecasts, the understanding of the underlying effects has remained incomplete so far. In this paper, we develop a more comprehensive theoretical framework of the connection between the statistical and the economic properties of day-ahead electricity forecasts. We find that, apart from the accuracy and the bias, which have already been extensively researched, the correlation between the forecast errors and the market price spread determines the economic implications - a phenomenon which we refer to as 'correlation effect'. Our analysis is completed by a case study on solar electricity forecasting in Germany which illustrates the relevance and the limits of both our theoretical framework and the correlation effect. • The economics of short-term electricity forecasts are studied analytically and empirically. • The value and the risk of forecast-based electricity trading are evaluated. • We find that the economics depend on the correlation of forecast errors with prices. • Hence, the most accurate forecast is not necessarily the most accurate. [ABSTRACT FROM AUTHOR]

A task of the Arctic integrated development affects the development of the new safe and waste-free technologies of waste processing using hydrogen electric power generation. This problem is multifaceted and concerns both large port cities and small towns, mines, islands, platforms, mining and processing plants, etc., despite the fact that many of them have not removed the wastes from their previous activities. The presence of melting permafrost, especially in the Western part of the Russian Arctic, high logistics costs, a small number of indigenous people and mainly rotational method of development make use of new technologies for the production of electricity, heat, water treatment, which provide the use of hydrogen power on the basis of liquefied natural gas (LNG). The use of LNG as a fuel is not effective enough, especially in the Arctic, given the low efficiency of diesel and gas turbine power plants, as well as the environmental degradation from their use. A more effective, environmentally friendly and integrated solution is the use of hydrogen electric power generation together with hydrogen fuel cells (HFC). The structure and method of waste-free technologies of waste processing are analyzed. The structure of wastes is multifaceted and contains: the most common solid waste from industry and life, including natural and man-made landfills; liquid wastes including sewage sludge from household and rainwater, oil-containing and other industrial wastes; leachate from landfills, including landfill gases; wastes resulted from transportation and transshipment of oil products, etc. In the paper purification methods are described; industrial shipping equipment and its characteristics for the application at facilities of the Arctic are presented. These installations include: incinerators, installations for treatment and filtrate of sewage from municipal solid wastes (MSW), desalination plants of reverse osmosis, snow-and ice-melting installations, cleaning and filtration of flue gases with an emphasis on methods of electric cleaning, cargo arms for loading and unloading the oil products and hazardous wastes. The advantages of hydrogen sources and energy storage using LNG in the Arctic both in terms of energy efficiency and ecology, the possibility of their use in conjunction with the above waste treatment plants are shown. Characteristics of solid oxide fuel cells (SOFC) and solid polymer fuel cells and their scope are presented. For the most dynamically developing solid oxide elements, their characteristics in the traditional and cogeneration cycles are given and the scope of their application in small and distributed energy at power up to 10 kW is shown. Atmospheric hybrid schemes for thermodynamic efficiency are significantly inferior to schemes under pressure, but in large-capacity plants, for example, with coal gasification, they can be quite promising. Modern SOFC work under pressure of 7–9 bar; with the growth of their capacity over 1–5 MW in hybrid power plants (HPPs) it is necessary to increase the pressure up to 11 bar and even more. For HPPs with capacity over 10 MW, cogeneration cycle with gas turbines (CCGT) is the most efficient. The highest electrical efficiency of HPPs with the capacity over 10 MW reaches 75% with the use of CCGT and boilers at three pressure units with intermediate superheating. The paper presents the characteristics of traditional sources of electricity based on ship and aircraft gas turbine units operating on LNG, which can be used in autonomous power supply networks of Arctic facilities. Their advantages in terms of specific power in comparison with diesel power plants and storage devices are shown, but high LNG consumption and environmental indicators limit their use in the Arctic, taking into account the logistics problems. Comparison of the energy efficiency of traditional sources and hydrogen storage shows significant advantages of the latter, and if the efficiency of traditional sources increases with their power, the efficiency of storage devices does not change in the entire range of capacities. This circumstance makes the use of hydrogen sources and accumulators uncontested in the field of small capacities typical for Arctic consumers, especially taking into account the possibilities for safe and waste-free technology for processing industrial and life wastes. [ABSTRACT FROM AUTHOR]

The analysis of the concentration of furanic compounds in oil has been accepted as one of the most reliable methods to obtain information about the condition of the transformer's cellulosic insulation. In this paper, the relation between the moisture content of the paper and the rate of generation of 2-furfuraldehidyde (2FAL) is studied. A statistical study is carried out to determine if transformers with higher moisture contents in oil tend to present higher contents of 2FAL, and, to this end, a database with more than 20,000 historical records of transformers is utilized. This study is completed with a set of accelerated ageing tests of transformer cellulosic insulation pieces, conditioned with different moisture contents. The impact of the moisture content of paper on the relation between the degree of polymerization (DP) and the 2FAL concentration is determined, and a correction factor has been proposed to include this variable in a model. [ABSTRACT FROM AUTHOR]

• We decompose changes in industrial water demand in Scotland between 2012 and 2016. • Changes in sectoral water intensity a key factor explaining fall in water demand. • Role of electricity generation policies aimed at encouraging renewables important. • Future changes in water availability, demand and technologies important to examine. Future climate scenarios predict significant changes in the availability of water resources at global and regional scales. Knowledge of the possible economic consequences of this are limited by a shortage of data linking economic activity with physical water use. Matching a unique premise-level dataset to economic indicators at industrial/sector level, this paper undertakes a decomposition of changes in industrial water demand for Scotland between 2012 and 2016. Results highlight the importance of taking a sectoral approach, as changes in sectoral water intensity are significant. Furthermore, changes in the structure of the economy, i.e. a move away from water-intensive industries, highlight further reductions in overall water consumption. By considering future scenarios for Scottish water resources, this paper identifies key multi-disciplinary research challenges to address the major obstacles in developing a climate-ready water policy, which also captures the potential economic opportunities for Scotland from an awareness of the role of water in the economy. [ABSTRACT FROM AUTHOR]

The rapidly growing of population in the developing countries and their lack of access to electricity, especially in the remote or rural areas, is causing huge challenges for on energy production. Energy is an enabler and a reliable energy supply is critical to sustainable socio-economic development for any nation. Most of Chad's people live in villages with no particular power supply system. Exploiting renewable energies is the only means of fostering development and improving people's welfare. This paper attempts at proposing an energy profile and storage model for Chad in vast remote towns. The paper addresses the key energy gap that is hindering on the development of such systems, it models and assess the potential on electricity generation and using hydrogen as surplus power storage system. A techno-econo-environmental survey on a solar-wind hybrid system in 25 towns in Chad is undertaken using NASA data and HOMER Software. Several hybrid scenarios of energy production and storage is analyzed. The results showed that in the electricity generation scenario, the average total NPC for the studied stations was $ 48164 and the average LCOE was $0.573. The lowest LCOE was related to Aouzou station with 0.507 $/kWh and the highest LCOE was obtained for Bol station with 0.604 $/kWh. In the simultaneous electricity and hydrogen generation scenario, the cheapest hydrogen ($4.695/kg) was produced in the "Grid" scenario, which was the same for all of the stations, with a total NPC of $2413770. The most expensive hydrogen ($4.707/kg) was generated in the "Grid-Wind" scenario and Bol stations with a total NPC of $2420186. The paper develops cost effective models for all hybrid systems combination for both electricity and hydrogen generation across Chad. These findings could help policy makers, investors and other developmental agencies make informed choices on energy access for sustainable development for rural communities in Sub Saharan Africa. • The wind turbine alone was the superior choice at no station in Chad. • The lowest LCOE (0.507 $/kWh) was associated with Aouzou station. • The lowest COH (4.695 $/kg) was associated with Grid scenario. • In electricity generation scenario, Abeche has the lowest emission (63.1 kg/year). • In hydrogen generation scenario, Aouzou has the lowest emission (1109 kg/year). [ABSTRACT FROM AUTHOR]

Small Island Developing States (SIDS) are often burdened with high electricity prices whilst being bestowed with excellent wind resources. Wind energy is the most proven of the modern renewable energy technologies and, in areas with a good resource, is often the cheapest form of electricity generation. Many small island states have yet to tap into their wind energy potential. Using the Caribbean island of Barbados as a case study, this paper applies basic engineering processes and a spatial planning methodology to determine an island's maximum potential installed wind capacity. In order to encourage repeated studies for other islands, publicly available global historical hourly weather data is identified and forms part of a technical assessment to estimate the expected annual energy yield. The paper highlights the complexities of wind energy development on small islands when compared with mainland countries and explores the key factors that are to be addressed if SIDS are to make use of their wind resource. Economic analysis of the expected annual energy yield for Barbados predicts a levelized cost of energy (LCOE) for wind of 0.13 US$/kWh (±0.01 US$/kWh), which compares favourably with other forms of generation that are an option for the island. • Whilst having excellent wind resources, many small island developing states (SIDS) have so far failed to take advantage. • A methodology is presented that uses open-source wind data to estimate the wind energy potential of any SIDS. • The cost of utility-scale wind compares favourably with other electricity generation options for SIDS. • Unique constraints to wind development on SIDS are presented, along with suggested solutions. [ABSTRACT FROM AUTHOR]

The microbial fuel cell (MFC) is an electrochemical electricity generation device that uses microorganisms to degrade organic matter to produce electrical energy. However, due to the limited charge generated by microorganisms, the output power of MFC is relatively low. Additionally, as a traditional MFC, it cannot store charge. In this paper, we designed and developed a dual-function capacitive MFC anode, which could generate electricity and store energy simultaneously. The capacitive anode was prepared by the direct growth of polypyrrole and ferric oxide on the carbon felt matrix, and the two materials played a synergistic effect. The power density of MFC equipped with the CF/PPy/Fe 3 O 4 -modified anode reached 6.61 W/m3, 29.8% higher than that of the CF/Fe 3 O 4 anode. When in the charging-discharging 45 min test(C45/D45), the total charge Q t released by the CF/PPy/Fe 3 O 4 anode was increased by 1431.74 C/m2 compared with the CF/Fe 3 O 4 anode. In this paper, the method of preparing a dual-function capacitive bioanode could store the electricity generated by microorganisms in the capacitive anode, which greatly improved the current output of MFC and solved its low output power problem. Schematic diagram of microbial fuel cell structure. [Display omitted] [ABSTRACT FROM AUTHOR]

• The coupled heat transfer process of rooftop photovoltaic shading units and indoor heat gain are analyzed. • The energy-saving potential of photovoltaic rooftops compared to traditional rooftops is revealed. • The energy-saving performance of photovoltaic and traditional rooftops under different roof reflectivity are summarized. • The impact of the optimal tilt angle on the power generation of the photovoltaic rooftop are discussed. • An energy-saving scheme for applying rooftop photovoltaic systems in hot summer areas is proposed. Rooftop photovoltaic panels can serve as external shading devices on buildings, effectively reducing indoor heat gain caused by sunlight. This paper uses a numerical model to analyze rooftop photovoltaic panels' thermal conduction, convection, and radiation in hot summer areas as shading devices. The researcher builds an experimental platform to verify the model, exploring the potential for energy savings of photovoltaic rooftop units in the Wuhan area. The results show that after installing photovoltaic panels, the delay performance of the roof increases by 0.5 h, the roof heat flux is reduced by 41.7%, the peak temperature of the roof is reduced by 22.9 °C, and the daily heat gain is reduced by 74.84%. Finally, this paper discusses the impact of high-reflectance and low-reflectance roofs on the shading effect. The study finds that low-reflectance roofs are more energy-efficient in the hot summer, as high-reflectance roofs lead to a 10.8% increase in indoor heat gain when the photovoltaic panel is installed. Finally, a quantitative method for evaluating the comprehensive potential for energy savings is proposed, considering the electricity generation gain of photovoltaic panels and the comprehensive energy-saving efficiency of photovoltaic roofs, which generates a total potential for energy savings rate of 61.06%. The model presented in this paper provides theoretical guidance for analyzing the comprehensive energy-saving effects of photovoltaic rooftop systems and reveals the potential for energy savings of rooftop photovoltaic panels as external shading devices. [ABSTRACT FROM AUTHOR]

The difference between the scheduled and actual generation of electricity leads to disruption on the balancing markets that must be paid at the deficit or surplus price. To smooth and simplify the market interactions, each license holder (producer, large consumer, supplier, grid operator) must be a member of a Balancing Responsible Party (BRP). We propose an improvement of the method for transparently and equidistantly setting the imbalance, cost - revenue allocation at the level of BRPs to increase the competitiveness among them. The proposed allocation method is compared with two existing methods implemented by two representative BRPs in Romania. The novelty of our approach consists in fairly rewarding the BRP members that reduce the cost or penalizing those members that diminish the revenue using indirect cost and revenue and implementing the penalty/reward principle. In this paper, we prove that BRP members benefit from cooperating and BRP minimizes the costs of imbalances between the schedule and real-time electricity delivery. The gain of BRP members (BRPi) may vary from 19 to 226%. Furthermore, we simulate that by adjusting the initial imbalance with only 2 or 3 units (equivalent with a smaller imbalance), the costs considerably decrease by 23.7%, 35.6% respectively. • Balancing Responsible Party (BRP). • Cost-revenue of allocation methods. • Implementation of principle penalty/reward using direct and indirect cost and revenue. • Fairly rewarding the BRP members that reduces the cost or penalizing those that diminish the revenue. [ABSTRACT FROM AUTHOR]

This article analyzed the location and concentration of forest bioelectricity in Brazil, from 2000 to 2019, available from the National Electric Energy Agency (ANEEL) and used the following indicators: Location Quotient (QL), Concentration Index [CR (k)], Herfindahl-Hirschman Index (HHI), Hoover Index (H) and Coefficient of Gini (G). The main results showed that the supply of electricity from Brazilian forest biomass increased from 562.90 MW and 11 thermoelectric plants in 2000 to 3532.61 MW and 115 thermoelectric plants in 2019, providing an average growth of 10.15% yy of the granted installed power and 13.20% p.a. of thermoelectric power plants. The QL inferred a high concentration of energy supply from black liquor (Rio Grande do Sul, Paraná, Espírito Santo, Bahia, Maranhão and Mato Grosso do Sul) and forest residues in several states, mainly in the North region. At the state level, the CR (4), CR (8) and HHI indexes indicated a deconcentration trend. The identification of the location and concentration pattern that the greatest offer was associated with industrial pulp and paper complexes. These results can indicate to investors the impact of electric power generation in the sector and the most relevant location for the installation of new thermoelectric plants. [ABSTRACT FROM AUTHOR]

Solar-driven water evaporation has attracted tremendous attention for its potential applications in desalination, electricity generation, and sterilization. However, low efficiency, high cost, and low stability of solar-to-heat converting materials make it difficult for large-scale manufacturability. Herein, we propose carbon nanodots (CDs)/molecular fluorophores hybrid material with high solar-to-heat conversion efficiency, low cost, and large-scale production for efficient solar-driven water evaporation. The CDs/Fluorophores hybrid was synthesized at gram-scale by drying product solution obtained from hydrothermal synthesis of CDs. The CDs/Fluorophores hybrid exhibited a broad absorption spectrum range from the UV–Vis to NIR region in solid state with the internal solar-to-heat conversion efficiency of up to 98.8%. Furthermore, we fabricated an interfacial water evaporation structure using CDs/Fluorophores-coated paper. The evaporation system exhibited a high evaporation rate of 2.1 kg m−2 h−1 and solar-to-vapor energy efficiency of 133.9% under one sun irradiation. Our results suggest that CDs/Fluorophores hybrid is a very promising photothermal material for a series of practical applications in solar-driven water evaporation, photothermal catalysis, and photothermal therapy. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper investigates and optimises the thermal performance of deep closed-loop heat exchanger (DCHE) systems by applying a computational numerical approach. The investigated DCHE configuration accounts for two deep vertical boreholes, an injection and a production well, connected by a horizontal borehole at depth and an insulated pipeline at the surface, establishing an effective closed-loop system. First, a parametric sensitivity study explores the effects of the environmental, design and operating variables on the production temperature. The simulation uses realistic geological and geothermal conditions, depths, circulation rates and injection temperatures. Two complex numerical models are then solved for site-specific DCHEs in different geological scenarios: a foreland basin and a convergent margin hosting low-to-intermediate and high-temperature geothermal resources, respectively. Production temperatures beyond 40–60 °C and 100 °C, sustainable for both heat and electric power generation, are obtained, depending on the geothermal conditions and closed-loop dimensions. Furthermore, circulation rates of 0.02–0.04 m3 s−1 are cost-effective, and the system's efficiency and sustainability increase when a fluctuating and periodic heat extraction strategy is employed. When efficiently operated, DCHEs are a viable solution for renewable energy production and should be integrated into the local heat market and distribution network infrastructure. Earth and Planetary Sciences; Energy; Environmental Sciences • Reuse of dry and depleted abandoned wells to boost geothermal energy production. • Deep closed-loop heat exchanger (DCHE) as innovative technological solution. • Computational numerical approach for DCHE performance optimisation. • Sustainable closed-loop configuration for synthetic and real case studies. • Long-term DCHE thermal performance improvement by monthly rotation practice. [ABSTRACT FROM AUTHOR]

Since its beginning, the computational performance of numerical optimization techniques has depended on utilizing efficient mathematical formulations to deal with large-size problems successfully. This fact is manifested in the unit commitment literature. Several approaches have been proposed to handle the complexity of accurately modeling real power systems. However, most of these methodologies focus on strengthening the technical features' representations by reducing the number of constraints and variables of the associated optimization problem or approximating its relaxed feasible region to the integer one to improve resolution processes. Hence, the state-of-art of these effective procedures is periodically studied under operational research and commercial solvers developments. Nevertheless, the formulation comparisons frequently obviate analyzing the impact of the balance equations on the computational burden of the unit commitment problem. This constraint links every single technical restriction along the time span and sometimes provides an ample optimization space, sometimes a narrow one, directly affecting resolution proceedings. It can impose an electricity generation equal to demand, allow production excesses, include non-served energy, or establish profit-based relationships. This paper presents a computational analysis of the most popular balance equations, detailing solver performances and determining these methodologies' tightness, compactness, and arduousness. Therefore, 1010 case studies were run utilizing different input profiles and optimality-convergence criteria. • The computational burden of the unit commitment balance equations is studied. • The tightness and compactness of widely utilized demand constraints are determined. • The "arduousness" concept is introduced to improve predictions on MIP resolutions. • The implications of using stable or intermittent thermal-load profiles are analyzed. • A formulation comparison benchmark with big-size optimization problems is proposed. [ABSTRACT FROM AUTHOR]

The Balancing Mechanism, managed by the British electricity system operator, National Grid ESO, is designed to maintain a balance between electricity generation and demand. It achieves this by purchasing extra generation (or demand reduction) through accepted offers and extra demand (or generation reduction) through accepted bids from Balancing Mechanism Units (BMUs) in real-time. The current manual approach for instructing BMUs becomes increasingly challenging as access to the market widens and the number of BMUs grows. This paper introduces a proof-of-concept optimisation model to assist Control Room engineers in making optimal decisions for a large number of BMUs. We outline the requirements for instructing BMUs, provide their mathematical formulation, and illustrate this using simple examples. Computational performance results based on test cases with up to 500 units are presented. • There is a growing need for automation for balancing Britain's electricity system. • A subset of balancing requirements outlined for Great Britain. • Mathematical programming formulation proposed, incorporating requirements. • Tests and validation of the developed formulation. • Control room decision-support discussed, highlighting challenges and necessities. [ABSTRACT FROM AUTHOR]