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China's paper production accounted for nearly a quarter of the world's total paper production in 2010. In this study, 23 energy saving technologies applicable to the pulping and papermaking process in China are identified and analyzed. The conservation supply curve (CSC) method is employed to assess the technical and economic aspects of energy conservation. The fuel CSC for Chinese pulp and paper industry shows the cost-effective and technical fuel conservation potential is 180 PJ and 254 PJ, accounting for 27% and 38% of total fuel used in 2010, respectively. The CO 2 mitigation potential related to the cost-effective fuel efficiency is 17 Mt CO 2 and the technical potential is 24 Mt CO 2 . The electricity CSC shows the technical electricity conservation potential is 2316 GWh, representing 4% of total electricity consumption. All of the electricity efficiency measures are shown to be cost-effective in this study. The CO 2 mitigation resulted from electricity efficiency is around 2 Mt CO 2 . In addition, sensitivity analyses for the parameters of penetration rate, discount rate, and energy price are conducted to assess their influence on the final results. [ABSTRACT FROM AUTHOR]

The need to view innovation policy through the lens of policy mixes has gained momentum given the growing complexity, the dynamics of real-world policy and the wide array of difficulties to address the current great societal challenges, notably the increasing pressure on the ecosystems that support our society. One of the main challenges concerning the transition towards bioeconomy, is to gain a more in-depth understanding on the policy mix to stimulate innovation in sustainability transitions. Our paper aims at enriching the portfolio of empirical case studies on policy mixes for innovation and sustainable transitions, by investigating the development of the policy mix underpinning the sustainability transition of the pulp and paper industry in Sweden. We apply a case study approach which draws on event history analysis, semi-structured interviews with industry and policy makers, literature reviews, a participative workshop with stakeholders from the pulp and paper industry, as well as on the IEA databases on climate change and energy efficiency policies and measures. Our analysis emphasises coordination, timing and scale in policy mixes as important elements to understand how instruments interact to accelerate sustainability transitions. The mapping of the policy mix shows that destabilising policies were crucial for accelerating the transition process of the industry. Prior to novelty creation policies, destabilising policies (e.g. environmental policies) were needed for 'innovation policy instruments' to be effective. More specific instruments (e.g. carbon tax), targeting particular functions of the innovation systems, require 'on-the-ground' policy intelligence and benefit from close interaction with industry. [ABSTRACT FROM AUTHOR]

Pulp and paper mill effluent (PPME), a rich cellulosic material, was found to have great potential for biohydrogen production through a photofermentation process. However, pretreatments were needed for degrading the complex structure of PPME before biohydrogen production. The aim of this study was to gain further insight into the effect of an ultrasonication process on PPME as a pretreatment method and on photofermentative biohydrogen production using Rhodobacter sphaeroides NCIMB. The ultrasonication amplitudes and times were varied between 30–90% and 15–60 min, respectively, and no dilution or nutrient supplementation was introduced during the biohydrogen production process. A higher biohydrogen yield, rate, light efficiency and COD removal efficiency were attained in conditions using ultrasonicated PPME. Among these different pretreatment conditions, PPME with ultrasonication pretreatment employing an amplitude of 60% and time of 45 min (A60:T45) gave the highest yield and rate of 5.77 mL H 2 /mL medium and 0.077 mL H 2 /mL h, respectively, while the raw PPME without ultrasonication showed a significantly lower yield and rate of 1.10 mL H 2 /mL medium and 0.015 mL H 2 /mL h, respectively. The results of this study demonstrated the potential of using ultrasonication as a pretreatment for PPME because the yield and rate of biohydrogen production were highly enhanced compared to the raw PPME. Economic analysis was also performed in this study, and in comparison with raw PPME, the highest net saving was $0.2132 for A60:T45. [ABSTRACT FROM AUTHOR]

The Swedish pulp and paper industry (PPI) must increase energy efficiency to remain competitive on the global market, which has experienced entries from countries with cheaper energy and raw material supplies. Interactions among variables for energy use, production, energy management, electricity price and firm characteristics (FC), in different types of mills, i.e., pulp, paper and integrated mills, in Sweden from 2006 to 2015 indicate that correlations among the studied variables were different in different types of mills. This difference between types of mills seemed to originate partly from varying accessibility to production residue that could be used for energy. For all types of mills, variation of electricity prices did not correlate significantly with energy efficiency during the study period. The studied FC were firm's age, number of employees, number of companies in company group, net sales and profit for the year. Energy efficiency was more affected by the variables characterizing energy and production compared to the variables representing FC. This study also suggested presence of possible discrepancies between FC that were perceived as barriers to energy management towards energy efficiency, according to previous studies, and what was shown by the data combining variables representing energy use, production and FC. [ABSTRACT FROM AUTHOR]

Abstract: The pulp and paper industry is one of the most energy-intensive industries worldwide. In 2007, it accounted for 5% of total global industrial energy consumption and 2% of direct industrial carbon dioxide (CO2) emissions. An energy audit is a primary step toward improving energy efficiency at the facility level. This paper describes a plant-wide energy audit aimed at identifying energy conservation and CO2 mitigation opportunities at a paper mill in Guangdong province, China. We describe the energy audit methods, relevant Chinese standards, methods of calculating energy and carbon indicators, baseline energy consumption and CO2 emissions of the audited paper mill, and nine energy-efficiency improvement opportunities identified by the audit. For each of the nine options, we evaluate the energy conservation and associated CO2 mitigation potential. The total technical energy conservation potential for these nine opportunities is 967.8terajoules (TJ), and the total CO2 mitigation potential is equal to 93,453tonnes CO2 annually, representing 14.4% and 14.7%, respectively, of the mill’s total energy consumption and CO2 emissions during the audit period. [Copyright &y& Elsevier]

This paper presents a comparison between four gasification-based biorefineries integrated with a pulp and paper mill. It is a continuation of 'Transportation fuel production from gasified biomass integrated with a pulp and paper mill - Part A: Heat integration and system performance'. Synthesis into methanol, Fischer-Tropsch crude or synthetic natural gas, or electricity generation in a gas turbine combined cycle, were evaluated. The concepts were assessed in terms of GHG (greenhouse gas) emissions and economic performance. Net annual profits were positive for all biofuel cases for an annuity factor of 0.1 in the year 2030; however, the results are sensitive to biofuel selling prices and CO 2,eq charge. Additionally, GHG emissions from grid electricity are highly influential on the results since all biofuel processes require external power. Credits for stored CO 2 might be necessary for processes to be competitive, i.e. storage of separated CO 2 from the syngas conditioning has an important role to play. Without CO 2 storage, the gas turbine case is better than, or equal to, biofuels regarding GHG emissions. Efficiency measures at the host mill prior to heat integration of a gasification process are beneficial from the perspective of GHG emissions, while having a negative impact on the economy. [ABSTRACT FROM AUTHOR]

Abstract The paper drying process has the highest level of energy consumption in the pulp and paper production process. Analysis and optimization of the energy system during the paper drying process is critical for improving the energy efficiency of the entire paper mill. In the existing model for the paper drying process, the solution requires accurate boundary conditions such as the air temperature and humidity of the pocket area and the cylinder surface temperature, which are very difficult to obtain in the papermaking process. This can result in significant deviations between the model solution and the actual production process. This paper focuses on the single-tier dryer cylinder-based paper drying process that has been widely used with high-speed papermaking machines in recent years. A mathematical model is proposed based on real-time data. The verification via industrial production demonstrates that the proposed model is reliable for the paper drying process. Based on the simulation results, two optimization operations have been proposed. The energy consumption decreases from 1.51 t steam/t paper to 1.44 t steam/t paper, 4.6% of the steam and 1.26 × 106 RMB can be saved for a medium-scale paper mill with the annual production capacity of 105 t paper. Highlights • Mathematical model for the single-tier cylinder based paper drying process is proposed. • Both the steam-condensate system and the paper drying process are considered. • The simulation results are verified by the industrial data from a papermaking enterprise. [ABSTRACT FROM AUTHOR]

This paper presents an inclusive approach with focus on energy use and recovery in wastewater management, including wastewater treatment (WWT) and sludge handling. Process data from three Swedish mills and a mathematical model were used to evaluate seven sludge handling strategies. The results indicate that excess energy use in WWT processes counters the potential energy recovery in the sludge handling systems. Energy use in WWT processes is recommended to aim for sufficient effluent treatment, not for sludge reduction. Increased secondary sludge production is favourable from an energy point of view provided it is used as a substrate for heat, biogas or electricity production. [Copyright &y& Elsevier]

Abstract: Energy conservation is a central concern of the current industrial world, where increasing efficient energy usage is the only way of reducing a high energy demand. In the present study the optimization of a pulp and paper mill with a cogeneration plant has been carried out. The optimization was realized with a methodology which includes exergy, exergoeconomics, thermoeconomics and pinch analysis. The proposed methodology was useful in determining not only the best plant operating conditions but also establishing the components or subsystems with the highest irreversibilities. As a result of the study, operation changes in the recovery boiler, the turbogenerator, the thermal treatment and the deaerator were realized. Due to the higher irreversibility in the actual evaporator line, a new line of evaporators was proposed. Also, an innovative heat recycling technology as to the use of heat transformers was proposed in order to reduce waste heat discharged to the atmosphere. The results obtained with the proposed methodology, which integrates the different optimization methods, allowed reaching higher efficiencies and lower operational costs than those obtained with the optimization methods working separately. [Copyright &y& Elsevier]

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: The heat recovery system (HRS) is a vital part in a paper machine when it comes to the overall energy economy in papermaking. For a typical newsprint machine more than 60% of the exhaust energy from the dryer section can be recovered, resulting typically in a regain of about 30MW. The synthesis task of a HRS is a decision process where the target is on the one hand to achieve maximal energy recovery and on the other hand to obtain it with minimal investment costs. These goals are contradictory and thus the problem is to find a solution minimizing the overall costs, considering simultaneously both energy and investment costs. One further challenge is how to take into account known variations in the parameters so that the design is robust, i.e. it is capable of handling all evolving situations and furthermore the design should be the most economical one when also considering the duration of all expected operational situations. In this work a hybrid method based on evolutionary programming and non-linear programming for the synthesis of robust and optimal heat recovery systems (HRS) for paper machines is presented. Variations and uncertainties on process parameters are modeled with probability distributions and the cost of the utilities are thus obtained as an integrated value of all different situations expected to evolve. The importance of obtaining a robust design is shown in a case study. [Copyright &y& Elsevier]

Abstract Long term electricity consumption forecasting has been extensively investigated in recent years in different countries due to its economic and social importance. In this context, the long term electricity consumption projections of a country or region are highly relevant for decision-making of companies and organizations operating in any energy system. In this paper, it is proposed a methodology that combines the bottom-up approach with hierarchical linear models for long term electricity consumption forecasting of a particular industrial sector considering energy efficiency scenarios. In addition, the Bayesian inference is used for model parameter estimation and, enabling the inclusion of uncertainty in the forecasts produced by the model. The model was applied to the Brazilian pulp and paper industry and it was able to capture the trajectory of the real consumption observed during the 2008–2014 period. The model was also used to generate long term point and probability distribution forecasts for the period ranging from 2015 until 2050. Highlights • Bottom-up Bayesian extension for the long-term electricity consumption forecasting. • The proposed model combines the bottom-up approach with hierarchical linear models. • The proposed model considers energy efficiency scenarios. [ABSTRACT FROM AUTHOR]

Abstract With the increasing number of light-duty passenger car, a large amount of waste engine oil was produced yearly which has polluted the environment and wasted fossil resources. Extend engine oil drain interval and reduce its effect on engine emission is of great importance. In this paper, a kind of modified-sawdust engine oil filter was developed and the study focus on its effect on the emission characteristics and fuel consumption rate of spark ignite gasoline engine. This modified-sawdust engine oil filter was also compared with common oil filter. The tests were performed in four-cylinder direct injection gasoline engine at six different typical operating conditions. Various tests were proceed including the exhaust emissions measurement of nitrogen oxides (NOx), carbon monoxide (CO) and hydrocarbons (HC) as well as the fuel consumption rate measurement. The effect of engine oil change on engine emission and fuel consumption rate were also studied. Impurity element content of waste oil and kinetic viscosity were measured before and after modified oil filter was used. The results show that relative to common oil filter, the modified-sawdust oil filter has 0.4–2.1%, 3.7–7.5%, 1.6–13.3% decrease for CO, HC, NOx emissions, respectively. In addition, it significantly reduces oil consumption, and the three major emission species (CO, HC and NOx) was also reduced when fresh engine oil was adopted. These results indicate that the use of modified-sawdust oil filter is an effective choice to improve gasoline engine emission and fuel economy. Highlights • A modified biomass oil filter was developed and its effect on gasoline engine emissions and oil consumption rate were studied. • The modified-sawdust oil filter showed lower fuel consumption rate than common fiber-paper oil filter. • The modified-sawdust oil filter showed lower emissions of HC, CO and NOx than common fiber-paper oil filter. [ABSTRACT FROM AUTHOR]

Harmonizing the cleanliness and economics of energy is an effective means of integrating economic growth with carbon peaking goals, and realizing sustainable development in China. However, due to the existence of the energy trilemma, a worthwhile research question is how to fulfill the carbon peaking commitment while guaranteeing China's stable national development. Based on this, this paper not only discusses the nonlinear relationship between clean energy consumption transition and economic growth through threshold regression, but also simulates several scenarios of energy transition dynamics with different growth rates by using Oracle Crystal Ball software to forecast the future trend of China's carbon emissions up to 2030, aiming to find a transition scenario that can make the peak of carbon emissions appear without significant economic burden, so as to put forward countermeasures and suggestions to avoid falling into the energy trilemma in the process of fulfilling the commitment of carbon peaking. This paper finds that: firstly, there is an inverted U-shaped non-linear relationship between clean energy consumption transition and economic growth, with the inflection point of the inverted U-shape being 0.595; and secondly, only when energy transition exceeds 0.535 in 2030, the peak of carbon emissions (about 12,922.28 Mt) will occur. In summary, this paper argues that China should steadily advance energy transition, avoiding either too fast or too slow a pace (bring clean energy consumption transition to within the 0.535–0.595 range by 2030), in order to secure economic growth while honoring its commitment to peak carbon. Therefore, China should prudently design a coal exit strategy to avoid falling into the energy trilemma when promoting energy transition. Moreover, if China wants to further fulfill its commitment to carbon neutrality by 2060, it needs to continue to deepen the construction of green financial markets in order to better balance the relationship between energy cleanliness and economy. [ABSTRACT FROM AUTHOR]

• This paper presents efficient energy management for loads with and without EVs. • This is based on optimal scheduling of solar-powered battery energy storage system. • A case study of a practical system is investigated. • The model considers seasonal variation effects of power generation and EV charging. • The results of proposed model are compared with other models. The increasing adoption of electric vehicles (EVs) and variable energy usage patterns substantially strain the electrical grid; indeed, optimal energy management, monitoring, and utilization are required for the reliable operation of the grid. This paper introduces a novel model design of a solar-powered battery energy storage system (SPBESS) as a viable substitute for conventional demand-side management (DSM) and time of use (ToU) pricing schemes, intending to optimize energy management and utilization with IoT monitoring. In addition, the IoT-based prototype has been developed to monitor and control the proposed system. To validate the proposed SPBESS model, the study examines two distinct cases: one encompassing domestic loads and the other integrating EV loads alongside household demand. Using ToU pricing, it determines the optimal charging and discharging strategies for the SPBESS, evaluates their implications for the system configuration and grid ToU pricing, and quantifies the annual reductions in power purchases, electricity bills, energy costs, and carbon emissions. Moreover, the study comprehensively analyzes the optimal power exchanges between the photovoltaic system, battery energy storage system, and the grid, precisely considering the specific load requirements and grid ToU pricing. The conducted research findings manifest considerable decreases in energy costs, with the domestic load condition witnessing a reduction from $0.312 per kilowatt-hour to $0.245 per kilowatt-hour and the scenario involving EV and residential loads experiencing a decline from $0.27 per kilowatt-hour to $0.197 per kilowatt-hour. Furthermore, the annualized cost savings for cases 1 and 2 amount to $1,336 and $4,544, respectively, yielding substantial reductions in polluting gas emissions. Besides, the IoT-based constructed prototype model design for real-time power parameters monitoring and control shows the importance of IoT-based monitoring for remote load control, allowing users to maximize energy efficiency, resource utilization, and system visualization. [ABSTRACT FROM AUTHOR]

Integrating electric vehicles (EVs) into the electric power system poses significant challenges to grid operation and planning due to the potential constraints on the power system. To minimize grid congestion, the best option is to increase the production of photovoltaic (PV) energy for domestic use and EV charging stations. This paper addresses the nexus of technical, financial, and environmental effects of customer involvement in economic development and load management. In this paper, a new model design of solar-powered EV charging stations is proposed and implemented in HOMER Grid, and a case study has explored how economic, technical, and energy management benefits can be achieved through customer energy involvement and the integration of PV-based charging stations. The proposed PV-based charging stations contribute toward the energy management of the region, and the study observes the real-time optimal charging and discharging strategy of PV-based grid-connected charging stations. The case study results show that the investigated area can produce 1,070,804.096 MWh/year of energy through maximum customer involvement, consequently reducing overall energy costs. Moreover, the study demonstrates that the selected region can produce 86,961,688 kWh/year through the PV system, achieving 363,899 charging sessions per year, offering maximum advantages and facilitation for EV charging. The proposed model applicability shows that large-scale customer involvement can bring significant techno-economic benefits and attract regional investments. • This paper proposes a new design of a grid-tied renewable energy system. • It investigates the energy economics and environmental effects for a practical location. • The research examines energy management including PV systems and electric vehicles. • The results of proposed model are compared with other models. [ABSTRACT FROM AUTHOR]

[Display omitted] • PCM energy storage and PV/T coupled multi-source heat pump systems were combined. • The thermal performance, energy efficiency, and economy of the system were analyzed. • The performance of paraffin C17 and water as energy storage materials were compared. • The performance of six low-temperature PCMs applied to the system were analyzed. • Compared to the existing system, it saves 56 % of energy and 27.7 % of operating costs. To improve the application of renewable energy in the heating zone, as well as to address the limitations of air and water source heat pump. The study presents a PV/T (photovoltaic/thermal) coupled air–water source heat pump system integrated with phase change energy storage. A theoretical analytical model and TRNSYS simulation model of the system were developed to evaluate the thermal performance, energy efficiency and economics of the system. The performance of phase change energy storage was compared with that of water storage, and the effect of different phase change materials on the system characteristics. The results show that the coupled system achieves a seasonal performance factor of 2.3, a 56 % reduction in energy consumption, and a 27.7 % reduction in operating costs compared to a conventional gas boiler system. Comparative analysis with the water storage system showed that the system equipped with phase change materials performed well in terms of energy consumption, operating costs and heating stability. In addition, the density of the phase change material has a biased effect on the overall performance of the system. This paper can provide a reference value for the study of renewable energy heating systems in cold zone. [ABSTRACT FROM AUTHOR]

One of the key steps towards economic feasibility of wave energy conversion technology concerns scaling up to farms of multiple devices, in the attempt to reduce installation costs by sharing infrastructure, and a consequent drop in levelised cost of energy. Moreover, whenever wave energy systems are deployed in proximity (in so-called arrays), the exploitation of the hydrodynamic interactions between single devices is fully enabled, potentially increasing the final energy outcome. To achieve this in real (operational) time, the employed energy-maximising control strategies require control-oriented array models, able to efficiently describe the dynamics of these interconnected systems in a representative fashion. This can be, nonetheless, a difficult task when considering first principles alone, under small motion assumptions, for modelling purposes. Recognising the uncertainty associated to array numerical models obtained from the linearisation of simplified system equations around their equilibria, this paper presents models of several array configurations identified following a frequency domain approach on the basis of experimental data. Tailored tests on laboratory-scale devices have been designed and conducted in the Aalborg University (Denmark) wave tank facility, with the purpose of performing representative system identification of the wave energy systems arrays. The obtained models are validated on different representative sea states configurations, in controlled and uncontrolled motion operational conditions. The validation results are fully discussed and analysed in terms of standard error measures and time lag, while the obtained models are made freely accessible via a linked repository (named OCEAN), in the attempt to openly provide validated models for different array configurations. • Data-based modelling of wave energy system arrays from experimental data. • Different array layouts, up to three devices at different distances. • Validation made in uncontrolled and controlled (passive and reactive) conditions. • Freely available validated MIMO models of the different array configurations. [ABSTRACT FROM AUTHOR]

The growing concern for the environment and imperative need for technology-enabled energy efficient freight transportation have led to the development of dedicated freight corridors (DFCs) in many countries like Germany, Netherlands, Austria, and India. The rapid expansion of DFCs is needed to improve supply chain efficiency. DFCs have potential to decongest existing rail networks, reduce the modal share of road freight transportation, and decarbonize freight transport sector. This study attempts to use transition management theory for identifying enablers of DFC for the transition from road to rail freight transportation. Exploratory factor analysis (EFA) is employed to confirm the three-level transition management framework for these enablers. This paper also proposes an eight-level hierarchical total interpretive structural modeling (TISM) based model for explicating the inter-relationships among the enablers of DFC to decarbonize freight transportation and achieve sustainability in the freight transport sector. Eventually, this paper provides empirical evidence to identify and validate the enablers of DFC through the lens of transition management theory. This paper also highlights the role of 'adoption of advanced technologies' to achieve sustainability in freight transportation. The outcomes of this study also facilitate policy-makers in understanding and managing the key enablers of DFCs to decarbonize freight transport sector. • Pinpoints 14 enablers of dedicated freight corridor for the road to rail transition • Empirically validates the proposed three-level transition management framework • Strategic level enablers explain the highest proportion of the variance. • Advanced technology usage helps to attain sustainability in freight transportation. • Strategic level enablers have higher factor loading and form the base of TISM model. [ABSTRACT FROM AUTHOR]

Abstract Industry is one of the highest energy consumption sector: some facilities like steelworks, foundries, or paper mills are highly energy-intensive activities. Many countries have already implemented subsidies on energy efficiency in generation and utilisation, with the aim of decreasing overall consumption and energy intensity of gross domestic product. Meanwhile, researchers have increased interest into alternative energy systems to decrease pollution and use of fossil fuels. Hydrogen, in particular, is proposed as a clean alternative energy vector, as it can be used as energy storage mean or to replace fossil fuels, e.g. for transport. This work analyses the re-vamping of the energy generation system of a paper mill by means of reversible solid oxide cells (RSOCs). The aim is not only to increase efficiency on energy generation, but also to create a polygeneration system where hydrogen is produced. Application on a real industrial facility, based in Italy with a production capacity of 60000 t/y of paper, is analysed. First, the current energy system is studied. Then, a novel system based on RSOC is proposed. Each component of the systems (both existing and novel) is defined using operational data, technical datasheet, or models defined with thermodynamic tools. Then, the interaction between them is studied. Primary energy analysis on the novel system is performed, and saving with respect to the current configuration is evaluated. Even if the complexity of the system increases, results show that saving occurs between 2 and 6%. Hydrogen generation is assessed, comparing the RSOC integrated system with proton exchange membrane (PEM) electrolysis, in terms of both primary energy and economics. Results exhibit significant primary energy and good economic performance on hydrogen production with the novel system proposed (hydrogen cost decreases from 10 €/kg to at least 8 €/kg). Highlights • The re-vamping of the energy generation system of a paper mill is analysed. • Reversible solid oxide cells are used increasing efficiency on energy generation. • A polygeneration system where hydrogen is produced is also created. • Primary energy saving on energy facility generation occurs between 2 and 6%. • Significant primary energy and good economic performance on hydrogen production are performed. [ABSTRACT FROM AUTHOR]

Abstract Whilst a plethora of literature has viewed technological progress as one of the critical influencing factors in relation to energy consumption and CO 2 emissions, little effort has been made to identify the sectoral differences in the relationship between technological progress and CO 2 emissions. Thereby, this paper remedies the inadequacies in the extant literature by empirically investigating the impact of technological progress on CO 2 emissions, specifically taking into account its heterogeneous effect in various economic sectors. This paper first decomposes the effect of technological progress as taking place in heavy industry, in light industry, in construction industry, and in service industry. A panel quantile regression approach and a balanced city panel data model are then applied, covering the period 2001–2013 in China. The empirical results show that technological progress in heavy industry and light industry surprisingly facilitates a higher level of CO 2 emissions, despite its prominent contribution to energy efficiency improvement. Meanwhile, as distinct from the effect it shows in the heavy and light industries, technological progress in construction and service industries exerts a negative effect on CO 2 emissions. Additionally, this paper further discovers that the strength of the multiple impacts of technological progress also varies with the level of emitters. By studying the heterogeneous effect brought about by technological progress in different economic sectors and emitters, this paper provides a comprehensive understanding of the relationship between CO 2 emissions and technological progress. Highlights • The study considers the sectoral and scale heterogeneity of technological progress in relation to CO 2 emissions. • We apply a panel quantile regression approach to balanced city-level panel data. • Technological progress within different economic sectors exerts different effects on CO 2 emissions. • The role of technological progress in moderating energy intensity varies across emitters. [ABSTRACT FROM AUTHOR]

Abstract Simulation and modelling allow a range of offshore wind farm stakeholders to test and improve a project's viability in a cost-effective and safe manner. This paper presents a model developed to conduct detailed financial analysis of an offshore wind farm. It extends the current state of the art by employing stochastic time-series simulation modules performing in-depth analysis of the technologies, strategies and procedures applied during the installation, operation and maintenance, and decommissioning phases of a wind farm lifecycle. The model was designed for versatility and can consider both fixed and floating technologies, a wide variety of strategies, and any site specified by the user. Results include energy production, costs and the duration of activities at each stage. These populate financial spreadsheets, which calculate key performance indicators including the Levelised Cost of Energy. The model has been successfully validated against real-life case-studies where possible; published data; and uses sensitivity analysis to ensure the model is working as expected. Through a case-study, the paper demonstrates how 1) the model enables the identification of key cost and time drivers, facilitating scenario optimisation; 2) the stochastic nature of the model considers the impact of uncertain variables on results such as weather conditions and wind turbine failure rates; 3) the model can be used to assess different business models and financing structures. This comprehensive range of abilities means that the model is suited to a variety of end-users and meets the demands of a growing industry, striving to achieve further cost-reductions across a range of site conditions, technologies and markets. Highlights • A validated model that performs in-depth financial analysis of offshore wind farms. • Designed for versatility, it can consider both fixed and floating technologies. • The model identifies key cost and time drivers, facilitating scenario optimisation. • It considers the impact of uncertain variables on results such as weather conditions. • With a comprehensive range of abilities, it is suited to a variety of end-users. [ABSTRACT FROM AUTHOR]

Abstract Demand response programs offer efficient solutions for many power system problems, such as high generation cost, high demand's peak to average ratio, high emissions, reliability issues and congestion in generation, transmission and distribution systems. Their main function is to assist power systems during peak demand hours and also during contingencies. They are a subcategory of the family of demand side management (DSM) strategies. DR programs are classified into two broad categories; price-based DR programs and incentive-based DR programs. In order to exploit their full potential, DR programs must be implemented optimally. Such a problem, which here is referred to as "DR optimisation problem", is a hot research topic and has been frequently researched in the literature. This paper aims to review different research works on DR optimisation problems. Based on the conducted review, some directions for future research are proposed. Highlights • Demand response programs offer efficient solutions for many power system problems. • Their main function is to assist power systems during peak hours and contingencies. • To exploit their full potential, DR programs must be implemented optimally. • This paper reviews different research works on DR optimisation problems. • Based on the conducted review, some directions for future research are proposed. [ABSTRACT FROM AUTHOR]

Abstract The world is faced with various societal challenges related to e.g. climate change and energy scarcity. To address these issues, complex innovative systems may be developed such as smart grids. When these systems are realized challenges pertaining to renewable energy and sustainability may, in part, be solved. To implement them, generally accepted common standards should be developed and used by firms and society so that the technological components can be connected and quality and safety requirements of smart grids and their governance can be guaranteed. This paper studies a subcomponent of the smart grid. Specifically, the paper studies competing technologies for a standard means of interface between the smart meter and the concentration point for collecting meter data. Three types of communication technologies for the interface are currently battling for standard dominance: Power line communication, Mobile telephony, and Radio frequency. Nine relevant standard dominance factors were found: operational supremacy, technological superiority, compatibility, flexibility, pricing strategy, timing of entry, current installed base, regulator, and suppliers. The Best-Worst Method was applied to calculate the factors' relative weights. The results show that experts believe that Power line communication has a high chance of becoming dominant and that the most important factor affecting standard success is technological superiority. The relative weights per factor are explained and theoretical and practical contributions, limitations, and areas for further research are discussed. Highlights • This paper focuses on factors for technology dominance. • The focus lies on the interface between the smart meter and the central database. • Nine factors appear to be especially important in this specific battle. • Weights are calculated by applying the best worst method. • Power line communication has the highest chance of achieving technology dominance. [ABSTRACT FROM AUTHOR]

Abstract This paper explores the most influential aspects regarding the environmental and economic performance of zero-energy and zero-emission buildings and proposes a pathway for transition in building solutions. A representative zero-energy office building in Norway is investigated with alternative design solutions to achieve zero-emission status i.e., the extensive use of locally generated energy through photovoltaic (PV) panels and the use of materials with low embodied emissions, such as low-carbon concrete and wood. A life cycle environmental and economic assessment is performed to evaluate specific indicators during the building life cycle: cumulative energy (CED), global warming potential (GWP), and equivalent annual cost (EAC). The extensive use of PV panels was most effective in lowering the operational energy because it reduced the CED by about 30% compared to the building as-built. However, the extensive use of wood in the construction contributed the most to GWP reduction, with around 30% decrease compared to the building as-built. Finally, the differences in EAC were interestingly insignificant among the alternatives, with the investment costs dominating the EAC for all designs examined. The findings of this paper emphasise that a full compensation of the life cycle GHG emissions from materials is difficult to achieve through renewable energy, even with extensive use of PV panels, especially in a low-carbon grid situation as in Norway. A pathway strategy from zero-energy towards zero-emission buildings must therefore strongly focus on the materials' embodied energy and emissions because low operational energy demand is already a regulatory priority in most countries. [ABSTRACT FROM AUTHOR]

Abstract The assessment of building energy performance through dynamic simulations has been increasing significantly in recent years since it represents a key strategy for the correct design of highly efficient buildings. Results of dynamic energy simulations are affected by many uncertainties, and its reliability depends on the accuracy of the input variables. One of the most influential variables is the climate surrounding the building, a reason why the use of accurate weather data files is essential, but experimental datasets are not always available. In this context, this paper analyses numerical weather datasets obtained from different regional climate models by comparing them with real data; in addition, it evaluates their impact on the energy performance of a historical building in Asunción through dynamic simulations. The database of five different weather data sources is compared with observed meteorological data in order to assess their accuracy through statistical analyses. Moreover, some methodologies to estimate diffused and direct components of the global solar radiation are evaluated, with the objective of solving the problem of missing direct and diffused solar data components from the meteorological codes. Subsequently, weather data files are generated to quantify the influence of measured/simulated meteorological data on the evaluation of building energy performance. The results obtained in this paper show that the simulated meteorological data agree very well with real observations for the year under study. Also, the simulations of the building energy performance delivered similar values to those obtained using the real weather dataset. Therefore, the regional climate models can represent a reliable tool for building energy performance assessment, and mainly for the calibration of building energy models when measured weather data is not available. [ABSTRACT FROM AUTHOR]

Abstract In this paper we identify a concept of countries' biomass-related sustainability through a revision of the literature and the opinion of professionals, and identify the main reasons that prevent biomass from being a major source of energy production (adversities and constraints). The Interpretive Structural Modeling (ISM) methodology was used for establishing the causal and hierarchical relationships among the variables linked with the adversities and constraints associated with the production of biofuel from biomass and their impact on countries' biomass-related sustainability. At the base of the concept of biomass related countries' sustainability we identify an important constraint associated with the high energy production costs, but also the necessity of supporting new investments, which will drive technological innovations in this sector and allow for an increase in efficiency. The paper presents an innovative approach to the research of biofuel production from biomass by suggesting not only a concept of countries' biomass-related sustainability but also by exploring causal and hierarchical relationships between adversities/constraints of biofuel production and impact on countries' sustainability. Highlights • We develop a new concept of biomass-based sustainability of countries. • We implement an interpretive structural modeling approach. • We identify government policies and market costs as essential to innovation. • Economic may imply Social Sustainability. • There are interdependencies between Economic and Environmental Sustainability. [ABSTRACT FROM AUTHOR]

Abstract Recently, there is an upsurge interest of using biomass derived char products in various fields, in order to address some of the most urgent energy and environmental problems we are facing today, such as CO 2 emission, energy crisis and environmental pollution. In this review paper, most recent studies on biochar/hydrochar production, characterization and prospective utilizations are summarized. Fundamentals and reaction mechanisms of biochar/hydrochar formations are discussed in detail. The energy balance and economic flexibility of biochar production technology is also analysed. The effects of reaction temperature, feedstock types, and thermochemical conversion modes on biochar are compared. In addition, we highlighted benefits and potential challenges in promoting biochar application in energy and environmental fields, including the applications in adsorbents, precursor of catalysts, soil amendment, anaerobic digestion and composting, and electrochemical energy storage materials. This paper not only summarises recent advances in engineered biochar technology but also demonstrates insights on new directions for biochar research and development in the future. Highlights • Biochar has enormous potential for ever-increasing energy and environmental demands. • Formation, properties and applications of biochar/hydrochar are summarized. • Biochar properties are influenced by temperature, feedstock and conversion modes. • The mechanisms of biochar/hydrochar generation are comprehensively summarized. • Biochar applications in energy, waste management and agriculture are reviewed. [ABSTRACT FROM AUTHOR]

Abstract In this paper, a new version of shuffle frog leaping algorithm (SFLA) which called modified SFLA (MSFLA) is proposed. To drive the proposed method both local and global search mechanisms in the original SFLA are modified. The local search mechanism is modified by introducing the movement inertia equation of particle swarm optimization (PSO). Furthermore, the global search mechanism is modified using the crossover and mutation operators of genetic algorithm (GA). Also, the formulation of the combined heat, emission and economic dispatch (CHEED) problem considering the availability of wind and solar power is presented where the objective functions of the CHEED problem are converted into a single objective function using price penalty function. Then, the proposed MSFLA is employed to solve the problem of CHEED with wind and solar power. To show the effectiveness of the proposed MSFLA, different test systems with different scenarios are used. In addition, the scalability of the proposed MSFLA is tested using large-scale test systems. The results of the proposed MSFLA are compared with those obtained by other heuristic and non-heuristic published methods. The comparison with other methods proves the efficiency and the superiority of the proposed MSFLA over other methods in all scenarios. Highlights • A new version of SFLA is proposed in this paper. • This version is derived by modifying local and global search mechanisms in SFLA. • The proposed method is used to solve the CHEED problem with renewable sources. • The proposed method has been evaluated using different test systems and cases. • Results of all cases show the superiority of the proposed method over other methods. [ABSTRACT FROM AUTHOR]

Abstract In recent years, with the gradual deterioration of atmospheric environment in China, the "coal to electricity" project is being implemented by the government vigorously. Even though "coal to electricity" project has a positive impact on eliminating serious pollution and promoting clean energy, in the rural areas, the power grid enterprises have less interest in implementing this project. Aimed at this background, the present paper explored the economic benefits generated by the implementation of "coal to electricity" project of grid enterprises. The results indicate that the project carried out by grid company has poor economic performance during its life cycle, which could attributable to its large investment, irrational electricity price mechanism and the big seasonal difference between peak and valley power demand. Finally, based on the conclusion, this paper gives some specific suggestions for grid corporation to increase the economic efficiency of "coal to electricity" project, including reforming the existing irrational price mechanism, taking full advantage of distributed renewable energy and so on. Graphical abstract Image 1 Highlights • "Coal to electricity" project implemented by grid company has a poor economic performance. • The deficiency in economic performance mainly caused by large investment and irrational price mechanism. • Measures need to be taken such as reforming the existing irrational price mechanism or use distributed renewable energy. [ABSTRACT FROM AUTHOR]

Abstract Plate heat exchangers have been widely applied in numerous industrial applications since their first commercial exploitation in the 1920s. Enhancing the thermal-hydraulic performance of plate heat exchangers is of crucial importance for the energy conversion as well as for the improvement of the system economy, through savings in the capital investment. The efficiency of a plate heat exchanger can be improved either by optimizing its geometry or using heat transfer enhancement techniques. This paper provides a comprehensive review of previous works regarding the effects of chevron corrugation geometrical parameters on the performance of plate heat exchangers, and the application of heat transfer enhancement techniques in plate heat exchangers, focusing on passive surface techniques and the use of nanofluids. The objective of the paper is not only to describe relevant studies, but also to provide an understanding of the heat transfer mechanisms governing the results, and to evaluate and compare the different heat transfer enhancement techniques. In addition, prospective directions for future research are provided. The review indicates that for the chevron-type plate heat exchanger, the chevron angle is the most influential geometrical parameter by changing the flow structures in the single-phase heat transfer; meanwhile the chevron angle has a significant influence on the heat transfer regions characterized by convection in the two-phase heat transfer. An analysis based on the performance evaluation criteria suggests that the thermal-hydraulic performances of the studies with different geometrical parameters and enhancement techniques are generally higher at low Reynold numbers. Furthermore, the review and analysis indicate that the capsule-type embossing surface and the microstructured surface with a nano- and microporous layer are the enhancement techniques that present the highest performance in single-phase and two-phase heat transfer, respectively. Highlights • Analysis of the effects of geometrical parameters on the performance. • Analysis of the use of diverse heat transfer enhancement techniques. • Use of passive surface techniques and nanofluids are most commonly investigated. • Performance evaluation criteria are calculated based on the available data. [ABSTRACT FROM AUTHOR]

Abstract The present paper presents the methodology and development of a planning tool for the installation of marine renewable energy systems, which enables the identification of suitable areas for this purpose. The marine spatial planning is one of the challenges of the offshore renewable energies. This is one of the reasons to write this paper, because there are areas where the energy potential is great but with real limitations for installing an offshore renewable energy farm. This methodology is based on the development of automated and interactive GIS tools in order to enable the user to change inputs according to his research objectives. The developed tools are applied to a case study referring to the Portuguese coast and the obtained results enable the identification of several areas, suitable for the development of marine renewable energies projects. The methodology and the developed tools intend to be a contribution for the Maritime Spatial Planning of the Portuguese coast and can be applied to other countries as well whenever the necessary information is available. Highlights • Methodology and development of a planning tool for marine renewable energy. • Identification of suitable areas of installing. • GIS tools to change inputs according to his objectives. • Maritime Spatial Planning of the Portuguese coast. • Results identify suitable areas for marine renewable energies. [ABSTRACT FROM AUTHOR]

Abstract Wind turbines are emerging as one of the most promising and cost-effective renewable energy sources, due to their economical merits and technical maturity. It is important to accurately predict the aerodynamic performance of rotor blades for efficient design of wind turbine. Among the various numerical approaches, the vortex lattice method (VLM) is one of the most suitable models for wind turbine aerodynamics because the wind turbine mostly operates in the subsonic flow. However, it inherently cannot predict the nonlinear aerodynamic characteristics at a high angle of attack. In the current paper, a nonlinear vortex lattice method (NVLM) has been suggested to extend the existing VLM for handling the nonlinear stall and post-stall behaviors. This can be possible by finding a control point in the airfoil where the effective angle of attack is applied. This paper mainly discusses the development and validation of the NVLM for predicting the aerodynamic performances and the wake geometry against the measurements on the MEXICO rotor model. The comparison results show that the aerodynamic loads and tip vortex trajectories computed by NVLM are in significantly good agreement with the measured data. In addition, the complicated and unsteady wake structures are also analyzed using vortex particle method. Highlights • The nonlinear vortex lattice method can consider the post-stall behaviors. • The most suitable location of control point is half chord for vortex lattice method. • The strong wake interaction and tip vortex breakdown occur at low wind speed. • The wake structure becomes stable and expansion angle reduces at high wind speed. [ABSTRACT FROM AUTHOR]

Abstract Energy poverty in developing regions is a major global concern, with the rural areas of South Asia, South-East Asia and Sub-Saharan Africa being the most affected. The major residential energy consumption in these regions is for cooking and lighting, which is basically covered with traditional biomass and fossil fuels. This situation acts as a development barrier, while implying stress on resources and the environment. Solar home systems (SHS) can play an important role in overcoming this problem. Recent technological advances and cost reductions in lithium-ion batteries favour their use in such application. Domestic electric devices with outstanding energy efficiency are becoming the standard around the globe. This paper focuses on exploiting these innovations to provide a solution for domestic energy poverty in developing regions. The layout of a SHS that integrates a lithium-ion battery-pack and is complemented with LED lamps and an energy efficient multicooker is presented. The paper assesses the SHS in contrast with existing practices under domestic energy poverty, with consideration of the learning curve. It is concluded that the cost of energy of the SHS is slightly cheaper than the business as usual case on the short term, and notably cheaper on the longer run. Furthermore, a financing scheme is proposed to overcome implementation barriers. Government support is considered, and quantified based on the SHS carbon abatement and saved fossil fuel subsidies. A substantial share of the initial investment can be covered under such scheme. This case study allows to draw general conclusions on the potential of SHS as a solution for domestic energy poverty in developing regions, on the financing gaps that hamper implementation and eventually on the required actions to overcome these. Highlights • The state of the art of domestic energy poverty in developing regions is summarized. • A solar home system with lithium-ion battery is proposed as a solution. • The solar home system is assessed in contrast with current practices under energy poverty. • The solar home system is more cost effective and has an incremental cost advantage over time. • A financing scheme is suggested to overcome implementation barriers. [ABSTRACT FROM AUTHOR]

Abstract The safety operation and economic benefits of wind farms are paid more attention by industry and society. Therefore, it's necessary to evaluate the wind power projects to find the deviation between actual situation, forecast target and first-class level. The commonly used methods of post-evaluation are AHP and fuzzy comprehensive evaluation which have three problems to be solved. The first is AHP method can't represent the correlation among the indexes. The second is the uncertainty of project data and experts' judgment. The third is the rectangle membership function can't realize data classification between adjacent levels. ANP can describe the relationship between indicators to eliminate deviation caused by independent calculation. The trapezoidal membership function is useful for rapid classification data between adjacent levels by maximum membership degree. And the interval can utilize imperfect information to solve the limitation of point estimation. So this paper proposes ANP model and fuzzy comprehensive evaluation model based on trapezoid membership which are all improved by interval numbers to evaluate projects. The paper makes a calculation of Pinglu wind farm, and the result shows new model is more stable with accuracy and applicability for post-evaluation which can solve the problems such as incomplete information, data fluctuation and subjective judgment. Highlights • The paper aims at the post evaluation of wind power projects. • A new evaluation model is set up which is improved ANP and Fuzzy comprehensive evaluation model improved by interval number. • Improved ANP model by interval number is used to determine the weight of the index. • Improved fuzzy comprehensive evaluation model is based on trapezoid membership which is impoved by interval numbers. [ABSTRACT FROM AUTHOR]

Abstract This paper proposes a quantity-quality-based optimization method of indoor thermal environment design that emphasizes entransy and exergy analysis. We scrutinized the different focuses of entransy and exergy in examining an energy-related phenomenon or process, and pointed out the need for integrating entransy and exergy for the optimization of indoor thermal environment design. The proposed method contributes to identifying the most energy-efficient solution for attaining the same level of indoor thermal comfort for end users by quantifying the entransy and exergy efficiency of active technologies. With this method, a benchmark technical solution was properly determined and benchmarks for entransy dissipation and exergy loss during the process of thermal environment design were quantified. Entransy dissipation and exergy loss under common technologies were compared with the benchmark values. The concepts of relative entransy savings and relative exergy savings were defined as the evaluation indexes of technical energy efficiency. Referencing winter indoor thermal environment design for residential buildings in hot-summer and cold-winter (HSCW) regions in China, the proposed method was applied to assess the energy efficiency of different heating methods, including an inverter air conditioner, an "air source heat pump + floor radiation," a "wall-hanging gas heater + floor radiation," a "wall-hanging gas heater + radiator," and an oil-filled radiator. This paper recommended that the "air source heat pump + floor radiation" be used for residential buildings in winter in HSCW regions to improve energy efficiency. In addition, the optimization results of the proposed method were compared with that of traditional energy and exergy analysis methods. The results showed that the new method more accurately analyzed the energy flow in indoor thermal environment design, and therefore can serve as an improved way of thinking about follow-up studies on the optimization of heat pump units and the operation strategies of floor radiant heating systems. Highlights • Entransy concept for indoor thermal environment design. • Entransy dissipation and exergy loss in the entire energy flow were quantified. • New energy efficiency indexes-relative entransy/exergy savings were defined. • It contributes to optimizing the design and operation of energy systems. • Five typical heating systems were analyzed. [ABSTRACT FROM AUTHOR]

Abstract The solar chimney is one concept currently explored by scientists and designers for reducing heat gain and inducing natural cooling in both commercial and residential buildings. Solar chimneys can be installed on the building walls and roofs. In this sense, a significant amount of research work has been done on solar chimney since the 1990s. This paper presents an overview of transient mathematical models for solar chimneys with/without a phase change material. The review focuses on the Global Energy Balance (GEB) models and a short description of the main works is reported. The analysis of the literature on the solar chimney modeling using GEBhighlights that the transient mathematical model are scarce, from the authors' knowledge, there are only 24 published works and only six studies incorporated a phase change material (PCM) in a solar chimney. Five steady mathematical models available in the literature were analyzed, as well as the advantages and disadvantages of each model. Based on the analysis, it is concluded that the model - III and model - V are more appropriate to model the transient state with respect to the remaining models, and therefore the unsteady mathematical model –III and model - V were developed and shown. These models are highly recommended to be implemented as a solar chimney model in a Building Energy Simulation (BES) program. Finally, we propose a new transient mathematical model for a double-channel solar chimney, which incorporated a phase change material (PCM). This new mathematical model allows building designers and engineers to predict the potential benefit that a solar chimney with PCMmay have for ventilation. Therefore, this paper would provide a valuable reference for further research into the field of solar chimneys with a PCMand its applications. [ABSTRACT FROM AUTHOR]

Abstract Asia has become a major emitter of carbon emissions. To better achieve emission reduction targets, it is necessary to study the characteristics of carbon dioxide emissions in Asia and their emission reduction potential. Firstly, the gravity movement of Asia's carbon dioxide emissions and its leading forces are explored. Then, the Logarithmic Mean Divisia Index method is applied to find the driving factors governing carbon dioxide emissions. Furthermore, this paper establishes a theoretical model of carbon dioxide emission reduction. At last, the influencing factors are utilized to construct a decoupling index, which is used to describe the dependence of economic development on carbon dioxide emissions. The gravity center for Asia's carbon dioxide emissions was an overall movement towards southwest. However, the gravity center for carbon dioxide emissions per capita was an overall movement towards the southeast. The energy intensity effect was the most factor decreasing Asia's carbon dioxide emissions. Only five countries achieved theoretical reduction of carbon dioxide emissions over 2000–2015. However, three countries were failed to achieve the theoretical reduction of carbon dioxide emissions in this period. The economic development in most east Asia and southeast Asia countries was less dependent on energy-related carbon dioxide emissions over the period 2000–2015. Highlights • The gravity movement of Asia's CO2 emissions and its leading forces were explored. • This paper established a theoretical model of carbon dioxide emission reduction. • This paper constructed a decoupling index. [ABSTRACT FROM AUTHOR]

Abstract Resident satisfaction with governmental environmental protection is of great significance to environmental governance by the Chinese government. However, the impact of internet use on resident satisfaction with governmental environmental protection is complex, and the relevant empirical evidence is far from sufficient. Based on data from the Chinese Social Survey for 2013 and using OLS and ordered probit regressions, this study finds a significant negative relationship between internet use and resident satisfaction with governmental environmental protection. Further study suggests that an increase in different online content frequencies could reduce resident satisfaction with governmental environmental protection. Nevertheless, residents who are conservative or skeptical about internet information are more satisfied with the government's environmental protection. The conclusions of this study are consistent with the "negativity bias" theory, indicating that netizens focus greater attention on negative news related to environmental protection. Finally, this paper performs two analyses to ensure the robustness of the research results. First, considering the possible "self-selection" problem, this paper conducts a robustness test using the method of propensity score matching (PSM) and finds that the results are still consistent. Second, the sample is subdivided to analyse the regional differences in the impacts of internet use on resident satisfaction with governmental environmental protection. The results show that internet use has a significant negative influence on resident satisfaction with governmental environmental protection in eastern China, central China but has no significant effect in western China. In addition, the impact of internet use on urban resident satisfaction with governmental environmental protection is significantly greater than that of rural resident. Highlights • The effect of internet use on resident satisfaction with the governmental environmental protection is studied for China. • Internet use has significant negative impact on resident satisfaction with governmental environmental protection in China. • Residents who are skeptical about internet information are more satisfied with the governmental environmental protection. • Conclusions are consistent with "negativity bias theory", indicating that netizens pay more attention to negative news. [ABSTRACT FROM AUTHOR]

Highlights • Variable renewable energy integration diminishes synchronous inertia of power systems, resulting in vulnerable frequency instability. • Alternative options of fast frequency resources are required for secure and stable grid operation under high penetration of renewables. • This paper provides a critical review of potential sources of fast frequency reserves, and way forward to maintain secure and stable grid operation. Abstract The last few decades have seen renewable energy source (RES) integration growing at a rapid pace and this trend is likely to continue. The displacement of conventional synchronous plant, particularly at higher RES shares, is resulting in a 'lighter' system with low system inertia and reduced governor droop stiffness, leading to increased vulnerability to fast frequency stability. This paper presents a review of literature from the research and industry communities on possible sources of non-synchronous fast frequency reserve, considered as a potential solution to address diminishing synchronous reserve in RES integrated systems. The wide range of potential sources includes wind turbines, solar photovoltaic plant, energy storage, high voltage direct current (HVDC) systems, and demand response. The challenges and limitations associated with each approach are highlighted, and alternative strategies to maintain a minimum volume of security constrained fast frequency reserve are discussed based on the recent industry trends. [ABSTRACT FROM AUTHOR]

Abstract Giving policy advice related to climate mitigation requires insights that take both sectoral and technology effects (and their interactions) into account. This paper develops a novel soft-linking method for bridging the gap between sectoral top-down and technology rich bottom-up models. A unique feature of the approach is the explicit modelling of energy service demand in the top-down model, which creates a direct correspondence to the energy service production in the bottom-up model. This correspondence allows us, unlike previous work, to capture the macroeconomic impact of energy system investment flows. The paper illustrates the full-scale application of the method in the Danish IntERACT model, considering the unilateral introduction of coal carbon capture and storage in the Danish concrete sector. The policy leads to a reduction in the Danish concrete production, and in turn, a carbon leakage effect of 88%. Results also underscores the importance of accounting for the macroeconomic impact of energy system investment flows, as this is the source of approximately half of the policy-induced reduction in macroeconomic activity. Highlights • Introduces energy service demands in a computable general equilibrium model. • Identifies a highly consistent method for soft linking a top-down and a bottom-up model. • Highlights the full scale implementation of the method in the Danish IntERACT model. • Demonstrates the impact of energy system investments on the macro economy. • Shows that climate mitigation technologies may lead to significant carbon leakage. [ABSTRACT FROM AUTHOR]

Abstract Exergy-based methods are powerful tools for developing, evaluating, understanding, and improving energy conversion systems. This paper deals with integrated advanced exergy-based evaluations. In addition to conventional methods, advanced exergy-based analyses consider (a) the interactions among components of the overall system, and (b) the real potential for improving each important system component. The main role of an advanced analysis is to provide energy conversion system designers and operators with information useful for improving the design and operation of such systems. Splitting the exergy destruction, the capital investment cost, and the component-related environmental impact associated with each single component of an energy conversion system into endogenous/exogenous and avoidable/unavoidable parts and using a further splitting of the exogenous exergy destruction improves (a) our understanding of the processes that take place, and (b) the quality of the conclusions for improvement obtained from the analysis. This paper discusses the main features and some recent developments in the area of advanced exergy-based methods. Application of the method to a simple air refrigeration machine confirms the correctness of the approach. [ABSTRACT FROM AUTHOR]

Abstract This paper presents an investigation on the efficiency performance of the leading-edge undulated tidal turbine blades under the effect of waves. This biomimetic blade application is inspired by humpback whale flippers which provide these mammals with an exceptional manoeuvring ability that is mainly accredited to the beneficial of their leading-edge tubercles. The paper first presents the design, optimisation and experimental validation of these turbine models. With the aim of further validating the efficiency performance in a different testing environment as well as exploring the combined effect of the tidal current and wave interaction, a test campaign in a towing tank facility was conducted. Both regular and irregular wave conditions were considered combining with varying towing speeds to simulate the tidal current effect. The test results revealed that the leading-edge undulated turbine has a stable hydrodynamic performance over a combined range of current speeds and waves indicating that the overall performance was not affected considerably by the combined effects as opposed to the performance solely due to steady tidal current. Highlights • Biomimetic concept of applying leading-edge tubercles on a tidal turbine blade has been performed. • Leading-edge tubercles have significant impacts on the improvement of the hydrodynamic performance. • First practice of testing bioinspired tidal turbine blade in a towing tank facility under the wave and current. • Power generation performance under waves were evaluated and proved the effectiveness of leading-edge tubercles under wave conditions. [ABSTRACT FROM AUTHOR]

Abstract In 2011, the Danish government published an energy strategy for Denmark where one of the main targets are that Denmark should be a fossil-free society by 2050. Calculations show, that in order to reach this goal it is necessary to reduce the energy consumption of the existing building stock by 50% on average. Since a 50% reduction is obviously not possible for all buildings, those that can should aim for a so-called "deep energy renovation", i.e. reducing the energy consumption to a level corresponding to that of new buildings or even more. This paper describes two case studies where multi-story apartment buildings have undergone deep energy renovation. "Traneparken" where the expected energy use after renovation aimed at a level corresponding to that of a new building according to the Danish Building Regulations from 2015. "Sems Have" where the aim was to go even further and meet the requirements expected for new buildings in 2020, i.e. corresponding to the Danish "nearly zero energy"-definition according to the EPBD. The paper reports on calculations and measurements of energy savings, the economy of the projects and looks at the added benefits or co-benefits that residents, housing association and society in general have achieved in addition to significant energy savings. [ABSTRACT FROM AUTHOR]

Abstract Real-time electricity pricing could promote the adaptation of demand response programs in the presence of price volatility in smart grids. This paper proposes a real-time price-based demand response management model for heat and power consumers. In the proposed demand response program (DRP) the responsive electrical load can vary in different time intervals. In addition, total power and heat demands of the consumer are met, without any curtailment. The price uncertainty is envisaged through robust optimization for minimizing the worst-case electricity and heat demand procurement cost while flexibly adjusting the solution robustness. The proposed model can be easily embedded in the energy management system of the customer equipped with combined heat and power systems (CHPs), a power-only unit, a boiler unit and a heat buffer tank (HBT) and makes it possible to achieve a minimum cost. In this paper, the dual dependency characteristic of the heat and power in different types of CHPs has been taken into account. Furthermore, technical constraints, i.e. minimizing number of start-ups and shut-downs, ramp rate limits and minimum up/down-time limits of generation facilities are satisfied. Numerical simulations confirming the applicability and effectiveness of the proposed model are provided. According to the simulation results, there is a significant increase in the daily cost of the consumer without smart grid technology in comparison with the consumer employing the proposed real-time model. Highlights • A real-time price-based DRP is presented for heat and power consumers. • In the DRP, the responsive electrical load can vary in different time intervals. • The proposed model can be embedded in the energy management system of a customer. • The price uncertainty is considered through a robust optimization model. [ABSTRACT FROM AUTHOR]

Abstract This paper reports a review of an environmentally clean and efficient source of energy such as solid oxide fuel cell hybrid systems. Due to climate concerns, most nations are seeking alternative means of generating energy from a clean, efficient and environmental-friendly method. However, this has proven a big hurdle for both academic and industry researchers over many years. Currently, practical and technically feasible solution can be obtained via an integration of a microturbine and a fuel cell (hybrid systems). Combining the two distinct systems in a hybrid arrangement the efficiency of the microturbine increases from 25 to 30% to the 60–65% range. Hence, this paper outlines an engineering power generation solution towards the acute global population growth, the growing need, environmental concerns, intelligent use of energy with attendant environmental and hybrid system layouts concerning arising problems and tentative proposed solutions. Furthermore, advantages of a solid oxide fuel cell hybrid systems with respect to the other technologies are identified and discussed rationally. Special attention is devoted to modelling with software and emulator rigs and system prototypes. The paper also reviews the limitations and the benefits of these hybrid systems in relationship with energy, environment and sustainable development. Few potential applications, as long-term potential actions for sustainable development, and the future of such devices are further discussed. Highlights • Environmentally clean and efficient source of energy. • Integration of a microturbine and a fuel cell (hybrid systems). • Fuel cell modelling and SOFC hybrid cycles. • Limitations and the benefits of these hybrid systems in relationship with energy, environment and sustainable development. • Few potential applications, as long-term potential actions for sustainable development, and the future of such devices. [ABSTRACT FROM AUTHOR]

Abstract As a potential energy utilization paradigm, power and natural gas coupled system (PGCS) with gas turbines and power to gas (P2G) provides an effective approach to improve the energy efficiency with an environmentally friendly and reliable energy supply. To fully exploit complementary potentialities of PGCS and accommodate wind power with P2G devices under system uncertainties, a novel robust multi-objective power and gas flow (RM-PGF) incorporating a two-stage interval robust dispatch is proposed in this paper. Besides, to achieve a complementary energy utilization with an information privacy and a decentralized autonomy for these two sub-systems, this paper establishes a novel two-layer convex decoupled-synergetic framework for PGCS. In the outer optimization, the original nonconvex issue is convexified into an iterative second-order cone programming (SCOP) through a penalty convex–concave procedure (PCCP). While in the inner optimization, the convexified RM-PGF is solved with three decoupled-synergetic strategies, including alternating direction method of multipliers (ADMM), auxiliary problem principle (APP) and generalized Benders decomposition (GBD) based strategies. Finally, numerical simulations validate the superiority of the proposed RM-PGF with P2Gs for wind power accommodation, as well as the computational efficiency and robustness of these convex decoupled-synergetic strategies PCCP-ADMM, PCCP-APP and PCCP-GBD. Highlights • A robust multi-objective power and gas flow with P2Gs is firstly proposed. • A novel two-layer convex decoupled-synergetic framework is established. • More wind power is accommodated with P2Gs in two-stage interval robust dispatch. • A complementary energy utilization is realized with a decentralized autonomy. [ABSTRACT FROM AUTHOR]

Abstract Decision-making support (DMS) methods are widely used for technical, economic, social and environmental assessments within different energy sectors, including upstream oil and gas, refining and distribution, petrochemical, power generation, nuclear power, solar, biofuels, and wind. The main aim of this paper is to present a comprehensive literature review and classification framework for the latest scholarly research on the application of DMS methods in the upstream oil and gas industry. To achieve this aim, a systematic review is conducted on the current state-of-the-art and future perspectives of various DMS methods applied to different upstream operations (such as exploration, development and production) which take place prior to shipping of crude oil and natural gas to the refineries for processing. Journal and conference proceeding sources that contain literature on the subject are identified, and based on a set of inclusion criteria the related papers are selected and reviewed carefully. A framework is then proposed to classify the literature according to the year and source of publications, type of fossil fuel sources, stages of oil and gas field lifecycle, data collection techniques, decision-making methods, and geographical distribution and location of case studies. The proposed literature classification and content analysis can help upstream oil and gas industry stakeholders such as field owners, asset managers, service providers, policy makers, environmentalist, financial analyst, and regulatory agencies to gain better insight about their business activities with well-informed decision-making processes. Highlights • Systematic review on the current state-of the-art and future perspectives of various decision-making support methods applied to the upstream oil and gas sector. • To identify publication sources that contain literature on the topic. • To propose a framework to classify the literature according to a set of assessment criteria. • To identify the most commonly used decision analytics methods for upstream oil and gas operations (exploration, development and production). • To gain better insight about upstream oil and gas business activities with well-informed decision-making. [ABSTRACT FROM AUTHOR]

Abstract Addressing environmental concerns alongside economic development and energy transitions is a challenge for all countries and effective policy making requires approaches that can balance all these concerns. In this paper, combining a range of modeling methodologies is proposed as a way of addressing these questions in an integrated manner. The choice of models to be used would depend on the specific characteristics of the system and region being studied. One possible combination of models is discusses in this paper for the specific case of India. The Integrated Modeling Framework (IMF) proposed combines three modeling approaches – i) index decomposition to estimate impacts of structural changes in the economy, ii) constrained optimization to estimate least cost fuel options for the power sector, iii) input-output analysis to estimate economic impacts. The model results indicate that the mode of investment for climate change mitigation is a significant determinant of the impact on economic growth, incomes, and income distribution in India. In some scenarios, higher investments in green energy negatively affects low income households significantly more as compared to other households. The paper also demonstrates how the IMF can be used to determine the reasons for and therefore alleviate the negative impacts. Highlights • An Integrated Modeling Framework (IMF) combining three modeling methods is presented. • IMF built for India, but applicable for other developing countries also. • IMF useful to study balance between energy, environment, economy, and equity. • Negative trade-off between equity and renewable energy transition in some scenarios. • IMF useful for identifying ways to alleviate the negative trade-off. [ABSTRACT FROM AUTHOR]