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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: In this study the possibilities of making a cost-effective heat exchanger retrofit in a simulated thermo mechanical pulp and paper mill are analysed using advanced composite curves. The use of advanced composite curves is a fairly new method developed in Chalmers University, and they have not previously been used to analyse a mechanical pulp and paper mill. The simulated mill used as an example in this study has one TMP (thermo mechanical pulping) line, one paper machine, debarking and auxiliary systems. The results show that the advanced curves give valuable information on the system and provide guidance as to where to look for improvement potential. The relative costs of different improvements are in line with traditional knowledge of improvement costs. [Copyright &y& Elsevier]

Abstract: The paper industry is, with about 6% of the total worldwide industrial energy use, an energy-intensive industry. The drying section is with approximately 50% the largest energy consumer in a paper mill, energy use in this section is mainly heat use. Several options to decrease heat use in conventional multi-cylinder drying sections are investigated, calculating the effect on energy use. Optimization measures include a) decreasing the amount of water evaporation by applying additives in higher consistencies and by lowering the water viscosity, b) decreasing the heat use of water evaporation by increasing the dew point temperature of the dryer and c) increasing the amount of heat recovery by using exhaust air to not only pre-heat the incoming air but also to increase process water temperatures. These could all be achieved by retrofitting and/or choosing different processing conditions in existing factories. The combined thermal heat saving potential due to the optimization actions is 1.3GJh/t paper (or 32% of the drying section’s heat use) as compared to the reference situation. [ABSTRACT FROM AUTHOR]

Abstract: The success of any process improvement study depends on the quality of the available data and the way in which the plant-specific characteristics are incorporated in the applied conceptual models; in the context of process integration studies these issues are directly related to the rules followed during the data extraction stage. Improving energy efficiency in a pulp and paper Kraft mill requires the identification of the most promising heat recovery network retrofit projects. In a retrofit analysis using pinch technology/process integration methods, only the process streams associated to the existing heat exchangers and some outlet streams (such as wastewater/effluent streams and vents) with high potential for heat recovery are usually included, while the energy exchanged through non-isothermal stream mixing (NIM) or direct heat transfer (DHT) is often assumed fixed and is not considered in the analysis. Relaxing this assumption requires extracting more data to represent the DHT design configuration that exists in the plant. However, different data extraction options can be considered to represent the DHT configuration depending on the associated process/operation constraints. This work describes a systematic procedure to extract and analyse the impacts of DHT on the overall energy efficiency of a Kraft process with a specific focus on mixing along the pulp line and in water tanks. [Copyright &y& Elsevier]

To identify the influence of digital transformation on energy consumption, this paper introduces digitalization and energy elements into the multi-sector energy efficiency analysis model. Furthermore, this paper empirically tests the influence of digital transformation on energy efficiency from the micro level. The results show that the digital transformation indeed improves the enterprises energy efficiency, in which enterprises with higher energy efficiency are more affected. The improvement effect of digital transformation on enterprise energy efficiency continues to increase over time. In comparison, digital transformation shows more effective improvement effect on energy efficiency in enterprises that substantive transformation priority, with same group and maturity stage. Mechanism analysis shows that digital transformation can improve the energy efficiency of enterprises by reducing costs, increasing income, improving production efficiency and promoting technological innovation. In addition, the digital inclusive finance, government subsidies, intellectual property protection and service industry opening show positive regulatory effects. This paper proposes that, with the goal of peak carbon dioxide emissions and carbon neutrality, enterprises should actively increase digital investment and strengthen digital management of energy utilization. [Display omitted] • Digital transformation indeed improves the enterprises energy efficiency. • The promotion effect of digital transformation increases over time. • Digital transformation drives efficiency improvement and technological innovation. • Digital transformation contributes to cost reduction and benefit increase. [ABSTRACT FROM AUTHOR]

Abstract: A bottom-up methodological framework was developed and applied for the period 1985–2002, to selected manufacturing sub-sectors in Greece namely, food, beverages and tobacco, iron and steel, non-ferrous metals, non-metallic minerals and paper. Disaggregate physical data were aggregated according to their specific energy consumption (SEC) values and physical energy efficiency indicators were estimated. The Logarithmic Mean Divisia index method was also used and the effects of the production, structure and energy efficiency to changes in sub-sectoral manufacturing energy use were further assessed. Primary physical energy efficiency improved by 28% for the iron and steel and by 9% for the non-metallic minerals industries, compared to the base year 1990. For the food, beverages and tobacco and the paper sub-sectors, primary efficiency deteriorated by 20% and by 15%, respectively; finally electricity efficiency deteriorated by 7% for the non-ferrous metals. Sub-sectoral energy use is mainly driven by production output and energy efficiency changes. Sensitivity analysis showed that alternative SEC values do not influence the results whereas the selected base year is more critical for this analysis. Significant efficiency improvements refer to “heavy” industry; “light” industry needs further attention by energy policy to modernize its production plants and improve its efficiency. [Copyright &y& Elsevier]

This paper introduces an innovative decision support system for improving ship energy efficiency. It combines an engine optimization model and an artificial neural network (ANN). Real-time data regarding the ship and engine performance is obtained along a specific ship navigation, and an engine optimization model is built using Ricardo Wave software. This model is validated with high accuracy. Ship-specific parameters are derived, and fuel consumption is estimated using ANN models with different structures. The study identifies the most suitable ANN model with 1 hidden layer and 5 neurons based on error metric evaluation where the 0.99697 R2, 0.00035 RMSE, and 0.06470 MAPE scores are calculated. This approach offers a cost-effective solution for shipping companies to monitor critical engine parameters in real-time without investing in sensors or data collection systems. Thus, it contributes to dealing with the problem of the scarcity of analyzable data in the maritime literature, which is one of the significant issues in the papers related to energy efficiency, machine learning, and deep learning. It is an innovative approach since the parameters that are related to real-time operations rather than considering only instruction book information are aggregated, and the produced data is analyzed by an intelligent tool. • A system is proposed to control ship energy efficiency level by combining an optimization model and a neural network • A simulation model is created in the Ricardo Wave tool and the engine model is validated by actual data. • The ship fuel consumption is estimated by an artificial neural network based on the derived input parameters. • The prediction process is evaluated by error metrics to determine its success. [ABSTRACT FROM AUTHOR]

Energy efficiency is crucial for the sustainable operation of industrial and urban sectors. However, practicing engineers seldom have access to open-source tools that can readily evaluate and compare scenarios. In this work, a novel web-based tool called ROSMOSE is developed and proposed for analyzing the energy efficiency of industrial and urban systems and comparing potential process integration options. This optimization framework computes and graphically represents the minimum energy requirements, the pinch temperatures, and the Grand and integrated Carnot composite curves of process systems. Results are used to design utility systems that meet energy demands, while minimizing a specified objective function, such as total cost or environmental impacts. The Quarto environment, in which ROSMOSE is built upon, allows the integration of various open-source software and tools, such as database handling software, process modeling suites, and optimization solvers, along with interactive data visualization and reporting tools. This paper discusses the application of ROSMOSE for the energy integration and total site optimization of a dairy process consisting of milk treatment, and cream and cheese production to demonstrate the tool features. Other integration options, such as the use of heat pumps or solar panels, and the production of soft drinks or biogas as value-added byproducts, are also proposed and evaluated. As a result, from 75 % to 90 % in fuel savings and up to 80 % CO 2 emissions reduction in the dairy plant are identified by optimizing the utility systems integration. Moreover, complete electrification via heat pumps eliminates any fossil fuel needs and it results in 85 % energy savings and up to 96 % CO 2 emissions reduction. The activation of renewable electricity sources, such as solar power, made plausible this fully electrified scenario. Finally, optimized waste management strategies led to in-house fuel production and net export of biogas to the grid, but they also reduce cheese yield by prioritizing the biogas production from whey upgrading process. In this way, decision-makers have access to a clear performance comparison for a list of system configurations to draw informed trade-offs. A similar approach could be adopted to aid decision-making for the design and operation of other industrial and urban energy systems using ROSMOSE. [Display omitted] • ROSMOSE is an open-source energy integration, optimization and reporting tool. • Pinch analysis and other assessments of decarbonization strategies can be performed. • The process integration and waste valorization of a dairy plant is used as case study. • Above 75 % energy saving is achieved by process integration and optimal utility selection. • 96 % reduction in CO 2 emissions and on-site biogenic energy sources are identified. [ABSTRACT FROM AUTHOR]

Energy performance indices are widely used methods for determining and assessing the efficiency of buildings in operation. However, methodologies for indices that compare heat consumption among buildings and at higher temporal granularity than yearly are needed. This makes it possible for consumers to compare themselves to others to encourage them to improve their energy efficiency. For a district heating system, it also provides the district heating company with an overview of consumers' energy efficiency (and consumers' efficiency must be comparable). This is critical due to the interconnectedness of district heating systems, as consumers can indirectly have negative impacts on each other's operations. Having an overview of the efficiency of consumers can provide useful information for the district heating companies to detect unusual consumption and possible faults. This paper therefore has created a framework for the comparison of heat consumption among buildings, by taking into account various contextualities to make comparisons possible. The framework has been tested on a case study, and its capabilities are showcased. • Leveraging building metadata to allow energy consumption comparison among buildings. • Creation of heating consumption performance indexes for use by end-consumers. • Enabling of higher temporal resolution performance indexes increasing usability. • Fault detection based on performance indexes. • Showcasing of methodology on real consumption data from a suburb in Denmark. [ABSTRACT FROM AUTHOR]

The average electricity consumption per capita in China still has significant room for growth. Under the current rigid residential electricity pricing, it is very important to study how factors other than price can promote electricity conservation among residents. This paper uses micro-survey data of 2018 and 2020 to analyze energy efficiency and the rebound effect through a stochastic energy demand frontier model, as well as to examine the role of news propaganda in this context. The research conclusions are as follows: (1) News propaganda promoting electricity saving can weaken the rebound effect of electricity use, which can lead to better electricity savings. (2) The energy efficiency of residential electricity has improved significantly compared to previous years, and the rebound effect has decreased. (3) Electricity prices have a negative impact on electricity consumption, while income, household size, home area, and extreme temperatures have a positive impact. Based on these conclusions, we propose policy recommendations to address the current inflexibility in residential electricity pricing and to improve the efficiency of electricity use among residents. • News propaganda promoting electricity saving can weaken the rebound effect. • The energy efficiency of residential electricity has improved. • The rebound effect of residential electricity has decreased. • News propaganda can be a complement to the inflexibility of pricing policy. [ABSTRACT FROM AUTHOR]

Using the unique micro-data of industrial enterprises' Nitrogen oxides (NOx) and Sulfur oxides (SOx) emissions covering 58,725 enterprise-year observations, this paper investigates how digitalization affect energy efficiency. The empirical results show that regional digitalization can significantly promote the improvement of energy efficiency of industrial enterprises. Specifically, the result of PSM-DID method indicates that the impact of digitalization on energy efficiency is significantly enhanced by the "National innovative pilot cities" policy, while the dynamic result validates the continuity of industrial enterprises' energy efficiency. Moreover, regional digitalization has superior impact on enterprises within eastern region enterprises, the manufacturing sector, and with elevated liquidity and profitability levels. Finally, moderating effect suggests that technological innovation expand the positive impact of digitalization on enterprises' energy efficiency. This study confirms regional digitalization can promote the energy efficiency of Chinese industrial enterprises, providing the policy suggestions to the energy transition in China. • Measure the regional digitalization level of Prefecture-level city and the energy efficiency at Industrial enterprise-level. • Findings demonstrated that digitalization increases energy efficiency. • The impact of digitalization on energy efficiency can be enhanced by the "National innovative pilot cities" policy. • Technological innovation expands the positive impact of digitalization on enterprises' energy efficiency. [ABSTRACT FROM AUTHOR]

This paper explores whether the changes in energy intensity in Spain have led to improvements in the energy consumption levels or to a backfire effect offsetting the expected decrease. Jevon's paradox or backfire effect happens when a rebound higher than 100% causes energy efficiency improvement to raise energy consumption. To test Jevon's paradox or the backfire effect caused by energy efficiency actions, a Logarithmic Mean Divisia Index I (LMDI-I) is used for the Spanish economy. The period under consideration ranges from 2000 to 2015, when three national action plans were implemented. The main methodological novelty of this paper consists on to block the economic activity effect in a second decomposition round to better explore the effect of energy efficiency on energy consumption. As a whole, our results do not support Jevon's paradox for the sectors analyzed. However, they do warn about a possible backfire effect in the industry, transport and service sectors. Major findings follow these same findings when the activity effect is blocked. • Backfire effect caused by energy intensity is explored. • Focus is on the Spanish case from 2000 to 2015. • Main methodological novelty is to block the economic activity in a LMDI approach. • Results do not support Jevon's paradox for the sectors analyzed. [ABSTRACT FROM AUTHOR]

Abstract With the revolution of the traditional economic and social pattern based on centralized fossil energy consumption, the regional integrated energy system (RIES) has gained rapid development in recent years for achieving higher energy efficiency. This paper expands the Demand Response (DR) concept to the RIES and presents an optimal operation model of RIES considering the DR mechanism on the energy price. In this paper, a comprehensive DR strategy combining energy price and different loads is firstly developed to exploit the demand flexibility of RIES in the DR model established. Based on the DR modeling of the RIES, an operation optimization model with environmental, economic benefits and energy supply reliability as objective functions has been firstly established in detail. Secondly, a complete scheduling scheme is built based on the energy consumption characteristics and system operation characteristic of the integrated energy system. The model presented could reduce the cost of system without causing a significant amount of environmental pollution, and improve the energy efficiency of the RIES efficiently. Besides, the scheduling strategy proposed could also provide support for the operation strategy of integrated energy system under the energy development. Hopefully, this paper will provide reference for future research and engineering projects on DR programs in the RIES. Highlights • The typical structure of the RIES is introduced. • A DR model suitable for the RIES considering different loads is established. • An optimal operation model of the RIES based on DR is established. • The load in the RIES is affected not only by energy price but also by other loads. [ABSTRACT FROM AUTHOR]

Combining cost-optimal solutions to reach nearly zero energy buildings (NZEBs) in compliance with European policies is an ongoing challenge. Energy consumption can be reduced evaluating different configurations at the design stage and implementing the most appropriate solutions according to the building and the location. This paper develops a simulation-based optimization framework of cost-optimal choices and energy efficiency measures for new buildings. It combines energy and cost simulations using a sequential search technique to find the most effective combination of energy efficiency and renewable energy measures starting from a base configuration. The model is applied to a residential building prototype, taking into consideration hourly climatic data, construction methods, cost data and energy consumption. A cost database and a library of potential measures, related to envelope, appliances and systems, have been established and used within the optimization process. The potential impact of climate change on the estimated cooling loads has been included in the calculations. The paper shows the feasibility of European requirements for new NZEBs located in different cities. It describes how to best achieve the NZEB design at the lowest cost in 14 locations across Europe. Results highlight how the cost-optimal measures vary with climate and how in each location final selected options differ. Insulation and building tightness appear essential in colder climates, while efficient appliances and lighting are key measures in warmer locations. A key finding of the research is that a source energy reduction of 90% and beyond is feasible for new constructions in all locations. Results also show how efficient lighting and appliances considerably impact the building energy performance. The importance of integrating renewables and energy efficiency measures is confirmed as crucial to reach the NZEBs target. [ABSTRACT FROM AUTHOR]

This paper reports the results of analysis of technical and economic parameters on the specific cost of electricity production. The use of a particular technology determines the value of the investment needed for the construction of a power plant, its energy efficiency, internal electrical load of the power plant and its annual operating time. Besides, this cost is considerably dependent on the interest rate on the capital, fuel prices and environmental charges as well as, equally importantly, their variability in time. The variability in the prices of energy carriers and their mutual relations are inevitable for a number of reasons. As shown in the paper the change of the technical parameters in the range of the possible boundaries in a particular technology cannot considerably reduce the specific cost of electricity production. The reduction of the current price relation between gas and three-times cheaper coal (calculated per specific unit of energy) can considerably improve the profitability of the use of the gas-steam technology. When the ratio of the cost of fuel in the specific cost of electricity production is small, the impact of the fuel price on its value is also insignificant. [ABSTRACT FROM AUTHOR]

The energy benchmarking has been recognised as an effective analytical methodology and a significant management tool that helps to improve the efficiency and performance of the energy utilisation. Studies on energy benchmarking has been worldwide carried out in many areas for different objectives. However, there are few systematic theories to support the development of a reasonable energy benchmarking and to provide efficient application measures in machining systems. To overcome these challenges, based on previous studies we propose two significant rules of energy benchmarking in machining systems contributing to the development of the energy benchmarking and application. This paper describes the concept, content and scope of the energy benchmarking rules laying a solid theoretical foundation for the energy benchmarking research in the machining field and giving the research directions. Meanwhile, through application analysis of the rules, the energy benchmarking rules have wide application prospects in machining systems and play an important role in the energy-efficient production. [ABSTRACT FROM AUTHOR]

The regenerator plays a crucial role in determining the energy efficiency of green liquid desiccant air-conditioning systems. This paper presents a novel air gap membrane distillation regenerator featuring heat recovery and portable water production. Based on a validated numerical model, performance evaluation of the regenerator combined with an external heat exchanger is conducted in terms of regeneration capacity (RC) and energy consumption (Q in). The comparison of flow patterns demonstrates that the counter-flow has a slightly higher RC , while the parallel-flow has a significantly lower Q in and is therefore preferable from the perspective of COP. The effects of key parameters including feed and coolant desiccant inlet temperatures (T f,in & T c,in), mass flow rate (m dil), membrane length (L), air gap thickness (δ ag), desiccant concentration (X dil) and solution heat exchanger effectiveness (ε she) on the performance are investigated. The results show that T f,in is the dominant factor on performance compared to T c,in and m dil , and increasing L leads to a marked growth in both RC and COP regardless of the raised Q in. Additionally, it is found that narrowing the air gap from 3 mm to 1 mm can improve RC and COP by 69.9 % and 50.1 % respectively. As for ε she , it has no influence on RC but remarkable impacts on Q in and COP. Moreover, the heat recovery by the coolant channel is proved to save nearly 8 % of energy input under the involved conditions. Finally, the NSGA-Ⅱ based multi-objective optimization is performed to obtain the Pareto front for maximizing RC and minimizing Q in. And the optimal solution through TOPSIS decision-making offers a RC = 975.8 g/h and a Q in = 1938 W. The findings provide a basis for design and application of the novel regenerator. • A novel air gap membrane distillation liquid desiccant regenerator is investigated. • Parallel-flow pattern is superior to counter-flow pattern in terms of energy efficiency. • Heat recovery by the regenerator can achieve about 8 % energy savings. • Effects of various design and operation parameters on the performance are explored. • Trade-off between regeneration capacity and energy consumption is realized by NSGA-Ⅱ. [ABSTRACT FROM AUTHOR]

The paper addresses the issue of the transition from a traditional electrical system without automation to a newer active and smart system allowing the possibility of implementing Demand Side Management policies, for little islands not supplied by the main grid. In particular, the paper focuses on two main topics related to the definition of: • an effective control, monitoring and communication system as a tool for the full exploitation of the opportunities given by Demand Response policies; • some solutions for the automation of the end-users’ electrical installations, in order to offer to the utility flexibility to be used for the improvement of the generation and distribution efficiency. After a brief discussion on the international regulatory framework on automation and ICT applications for power systems, the paper presents a feasibility study, based on the characteristics of the island of Lampedusa, of a hierarchical architecture of a suitable control system and of some DSM enabling solutions for residential end-users. The proposed solutions are defined taking into account some main elements: • distribution grids in small islands are generally equipped with outdated and hardly automatable devices; • utilities in small islands have reduced budget for new investments; • not less important, the most of the inhabitants has low income and unfamiliarity with automation. Therefore, main features of the proposed DSM enabling technologies are low cost and ease of use. [ABSTRACT FROM AUTHOR]

Both energy and water are important resources for human and should be investigated in an integrated way. The paper examines the implications of improving energy efficiency for water resources to contribute to the understanding of energy-water nexus. The paper first develops a mathematical model to link energy efficiency and water withdrawals and consumption. Using the model and the UK energy and water data, the paper then investigates the implications of improving energy efficiency of thermal power technology for freshwater, tidal and sea water in the UK. Results show that when the energy efficiency increases averagely by 10%, the total water withdrawals decrease by 1.65 × 10 6 Megaliter (ML) per year, and the total water consumption reduces by 2.89 × 10 4 ML per year. The saved freshwater withdrawals account for 0.43% of total public water supply in England and Wales in 2013, and could support 138,462 households. The water resources have different sensitivity to the improvement of energy efficiency. The sea water withdrawals are the most sensitive to the improvement of energy efficiency, followed by tidal sea water withdrawals and freshwater withdrawals. Results provide significant informative implications for energy-water nexus, and suggests that it is time to consider improving energy efficiency to address the emerging energy and water challenges. [ABSTRACT FROM AUTHOR]

The Korean government has given efforts to reduce green-house gas emissions. In order to avoid the monolithic system that only focuses on reducing the emission without considering operational environments of firms, the government should encourage respective firms to improve their energy efficiency which wastes less energy but produces maximum economic revenue. This paper employed a DEA (Data Envelopment Analysis) model to measure energy efficiency of energy intensive manufacturing firms in Korea. Identifying and comparing the difference in efficiency score by using the simplified single-stage DEA model is not sufficient to give governments and firms meaningful policy implications related to energy efficiency improvement. To compensate for this insufficiency, this study extended the single-stage model into a two-stage model that includes two efficiency measures: pure energy efficiency which is only for energy-related process and economy efficiency which is for the pursuit of profit, to reach the improvement of total energy efficiency. By using the two-stage DEA model, it has identified that the difference from overall energy efficiency is not caused by pure energy efficiency but rather by economy efficiency. In addition, this paper statistically analyzed the effects of environmental variables such as firm size, possession of certified management systems and emission type. [ABSTRACT FROM AUTHOR]

The increasingly serious renewable generation curtailment in many countries reflects the drawbacks of current planning approach, which separates power source planning and grid expansion planning. In addition, resources in demand side should no longer be ignored in power planning with gradually mature policies related to energy efficiency and demand response. To fill this gap, this paper proposes a novel power system planning approach and builds an integrated source-grid-load planning model at the macro level. The model considers all the available elements in source side, grid side and load side together to find an optimal development solution from the perspective of the whole power system. The effectiveness and superiority of this model is verified through the comparison among separated source-grid planning, integrated source-grid planning and integrated source-grid-load planning in the case study. Then, an optimum development path for China's power sector till 2030 worked out by the model proposed in this paper is presented. Based on the in-depth analysis of the planning results, policy recommendations are also provided. [ABSTRACT FROM AUTHOR]

Industry poses one of the biggest challenges in the renewable energy transition. In this paper, fossil fuels in the European industrial sector are replaced by renewable energy using a novel tool, IndustryPLAN, a planning tool for the assessment of national industrial sectors. In a bottom-up approach, each industry sub-sector is addressed with energy efficiency and fossil fuel replacement measures based on best available and innovative technologies, and in a top-down approach, the fuel and electricity consumption per country is analysed and decarbonised. The results indicate that: 1. Known technologies can decarbonise most of the industrial sector; 2. Costs and efficiencies are improved by energy savings and electrification; 3. Limiting bioenergy consumption is a critical challenge, emphasising the key role of energy savings and electrification, and the alternative of using hydrogen or hydrogen-based electrofuels will make the transition more expensive and induce energy losses. A full transition to renewable energy and a decarbonised industry sector may be possible before 2050, however, this requires that all investments are sustainable from 2030 onwards and that grid electricity is fully decarbonised. This paper presents several pathways toward 100% renewable energy supply in the European industrial sector and discusses the implications of the outlined scenarios. • Four tangible 100% renewable energy scenarios for industry in EU27 + UK are established. • 100% renewable energy in industry is feasible before 2050. • Energy efficiency improvements are essential to limit biomass consumption. • Industry energy transition needs to be prioritised in short- and long-term planning. [ABSTRACT FROM AUTHOR]

The cost of heat savings in buildings increase as more heat savings are achieved and hence, alternatives other than savings typically become more economically feasible at a certain level of heat reductions. The challenge addressed in this paper is to identify when the cost of heat savings become more expensive than the cost of sustainable heat supply, so society does not overinvest in heat saving measures. This study first investigates the heat saving potentials for different countries in Europe, along with their associated costs, followed by a comparison with alternative ways of supplying sustainable heating. Furthermore, the levelised cost of supplying sustainable heat is estimated for both a single technology and from an energy system perspective. The results are analysed by assessing various parameters such as socio-economic costs and energy efficiency improvements in the national energy systems. The results demonstrate the economically feasible levels of heat savings and heat production for various European countries, highlighting differences in their national conditions and energy systems. The findings in this paper indicate that overinvestments in heat savings can be avoided by saving heat until a level around 30–50% of projected heat demands and supplying the remaining heat demand with sustainable heat sources. [ABSTRACT FROM AUTHOR]

Climate change and fossil fuel reserve depletion both pose challenges for energy security and for wellbeing in general. The top ten among them include: Decarbonising the world economy; Enhancing the energy efficiency and energy savings in buildings; Advancing the energy technologies; Moving towards energy systems based on variable renewables; Electrifying the transport and some industrial processes; Liberalizing and extending the energy markets; Integrating energy sectors to Smart Energy Systems; Making the cities and communities smart; Diversifying the energy sources; and Building more biorefineries. Presenting the contributions of selected conference papers published in the special issues of leading scientific journals (including all the papers from the current Energy special issue), this review demonstrates the capacity of the Conferences on Sustainable Development of Energy, Water and Environment Systems for generation of knowledge which could serve as the centrepiece of a pertinent response to those challenges. [ABSTRACT FROM AUTHOR]

With the facilitation of agricultural modernization, China's agricultural energy consumption continues to rise. This paper empirically tests the agricultural energy rebound effect and its influencing factors in China during 1999–2020. It is believed that the improvement of energy efficiency has not led to the expected energy-saving effect in agriculture due to the "Jevons paradox" of energy efficiency and energy consumption. The average energy efficiency of China's agricultural energy consumption was 0.446, and the average energy rebound effect was 68.9 %. The level of agricultural mechanization, the effective irrigated area of farmland and agricultural investment have a positive impact on the rebound effect of agricultural energy, and the direct effects are 0.062, 0.008 and 0.064, respectively, while agricultural labor force and energy price have a negative impact on the rebound effect of agricultural energy. In particular, technology spillover and scale spillover led by agricultural technology progress have strong negative space spillover effect. As it is argued, 1 % of agricultural technology progress can reduce 3.5 % of agricultural energy rebound effect in surrounding areas. In order to reduce the energy rebound effect, it is suggested to increase the subsidies to agricultural labors and rationally formulate regional differentiated energy regulation policies. • The internal mechanism of rebound effect is expounded from the view of producers and consumers. • The average energy efficiency of China's agricultural energy consumption was 68.9 % during 1999–2020. • The determinants of the agricultural energy rebound effect were further discussed by considering the spatial spillover effect. [ABSTRACT FROM AUTHOR]

—This paper proposes two real-time energy-oriented driving strategies to minimize the energy consumption for electric vehicles on highways with varying slopes. First, a novel strategy, called normalized-energy consumption minimization strategy (NCMS), adopts a designed kinetic energy conversion factor to convert the vehicle kinetic energy change into the equivalent battery energy consumption. By minimizing the total normalized energy consumption, the energy-orientated vehicle control sequence is calculated. In addition, a logic car-following algorithm is developed to enhance NCMS for avoiding collisions with the potential preceding vehicle on the journey. Second, an improved model predictive control (MPC) is developed with a hierarchical framework, which achieves a balance between optimization and computational efficiency. In the upper level, a global, coarse-grained, iterative dynamic programming is employed to penalize the MPC terminal state, while the lower level performs online rolling optimization of the vehicle within a moderate time step. Thirdly, the performance of the proposed driving strategies is verified through a traffic simulation to evaluate the energy efficiency improvement and processor computation time compared to dynamic programming and constant speed strategy. Finally, a vehicle-in-the-loop test is carried out to validate the feasibility of the proposed two novel driving strategies. • A normalized energy consumption model is presented, combining two energy usage. • A novel eco-driving strategy is developed based on the proposed energy consumption. • The algorithm suits both free traffic and car-following scenarios with safety. • The characteristics of the four eco-driving strategies are compared. • The proposed strategy is verified by both simulation and vehicle-in-the-loop tests. [ABSTRACT FROM AUTHOR]

The paper evaluates the potential energy efficiency benefits for dynamic sliding exterior shades suitable for windows of both new and existing buildings. In particular, the analysis outlined in the paper summarizes the energy performance of dynamic sliding shades when applied to windows for apartment units located in various US climates. A series of sensitivity analyses is performed using a detailed whole-building simulation coupled with modeling techniques of dynamic envelope systems to determine the optimal positions for the dynamic sliding shades to minimize the annual demand for US housing units. Several operation strategies are evaluated using continuous and stepped settings of the positions for the dynamic sliding shades using monthly, daily, and hourly adjustment frequencies. The results of the analyses indicate that the dynamic shades have significant energy efficiency potential for all US climates and design conditions with annual savings in HVAC energy end-use of over 50% especially in hot and mild climates. The performance of the dynamic shades is even higher for large and single-pane windows indicating that these systems can serve as retrofit alternatives to window replacements. • New and low-cost dynamic and insulated shading systems are introduced. • Energy benefits of the dynamic shades are assessed for residential buildings. • Optimal controls for the dynamic shades are determined for US climates. • Dynamic shades achieve over 50% reduction in heating and cooling energy use. [ABSTRACT FROM AUTHOR]

Due to the high dehumidification performance realized by removing adsorption heat by inner cooing, desiccant coated heat exchanger (DCHE) has been proposed and widely studied. The heat pump is usually used as the cooling and heat sources of the dehumidification system composed of DCHE because the cooling and heat capacity could be provided by the heat pump at the same time. Moreover, considering the advantage of low-grade thermal energy utilization, solar thermal energy can be used to further enhance the regeneration of DCHE to improve dehumidification performance and energy efficiency. In this paper, the solar-enhanced fresh air dehumidification system using DCHE driven by heat pump was proposed and a series of experiments were conducted under typical Shanghai summer high humidity conditions. The typical moisture removal of the system can be increased by about 15% to 10.14 g/kgDA and the COP could be further increased by over 25% to 5.39. In addition, the influence of different regeneration temperatures enhanced by solar thermal energy on the system has also been studied. Considering the dehumidification performance improvement and energy utilization efficiency, the optimal regeneration temperature is between 60 °C and 65 °C for the system proposed in this paper. • Moisture removal and COP can be increased by 6%–28% by solar enhanced. • Performance enhanced is more obvious when regeneration temperature is below 65 °C. • Solar enhanced dehumidification 1.43 (g·kgDA−1)/kW and 1.12 kg/kWh can be achieved. • Higher efficiency solar collectors will achieve higher solar enhanced performance. [ABSTRACT FROM AUTHOR]

Energy efficiency is a critical issue in data centre management, which is the foundation for cloud computing. The VM placement has a considerable impact on a data centre's energy efficiency and resource utilisation. The assignment of VMs to PMs is an NP-hard problem without an easy way to find an optimal solution, particularly in large-scale data centres. In this study, the VM placement problem is formulated as a constrained optimisation problem. The Genetic Algorithm (GA) is a suitable method for solving this problem in terms of the quality of the solution. However, GA is time-consuming to obtain an optimal solution in the large scale optimisation problem. Therefore, this paper focuses on accelerated GA for energy-efficient VM placement. As the most time-consuming element of the GA is the calculation of its fitness function, this paper simplifies this calculation through a new fitness function in GA. Simulation results of small-, medium-, and large-scale data centres demonstrate that our accelerated GA is faster than the standard GA and gives better quality of solution than the First Fit Decreasing (FFD) algorithm, respectively. The findings of our GA with the new fitness function reveal an 8% energy saving for our GA compared to FFD and a 66% reduction in our GA execution time compared to the standard GA with standard energy formula as a fitness function. The number of generations in our GA is reduced by about 50% in comparison with the standard GA. Moreover, we started with 3000 PMs in the large-scale dataset, and only 1086 PMs were actually used after running our GA. Therefore, we may switch off far more PMs for energy savings from our GA results than those from the standard GA. • Virtual machine placement problem formulated as a constrained optimisation problem. •It focuses on accelerated genetic algorithm for virtual machine placement. •Our algorithm can minimise residual resources using Taylor extension. •Our solution quality is better than FFD and standard genetic algorithm. •It reduces execution time and energy in large scale data centres. [ABSTRACT FROM AUTHOR]

Energy efficiency investments are essential to transition to a carbon-neutral economy. Nevertheless, despite being financially viable, many energy efficiency investment opportunities do not materialise. The existing literature attributes this situation to financial and non-financial factors. Research suggests that many firms focus only on direct energy savings and neglect non-energy benefits that include increased labour productivity. Up to date, due to the lack of high-quality data, few studies attempted to quantify how the energy efficiency investments affect firm-level outcomes other than the reductions in energy consumption. This paper overcomes this barrier by using novel data from a firm-level survey conducted by the European Investment Bank. The survey covers more than 15,000 firms in 27 European Union member states and the United Kingdom during 2018–2019. This study investigates the relationship between the energy efficiency investments and the labour productivity of the European firms and uses instrumental variables methodology to account for potential endogeneity. The results show a positive and causal relationship between energy efficiency investments and labour productivity. The findings of the paper suggest that firms can benefit much more from the energy efficiency investment than what is often assumed, and highlight a need for government policies that would increase firms' awareness of the non-energy benefits. • This paper investigates the link between energy efficiency investments and the labour productivity. • We apply IV models to 15,000 firms in 28 European countries during 2018–2019. • We find positive causal relationship between energy efficiency investments and productivity. • Governments should implement policies to increase firms' awareness of the non-energy benefits. [ABSTRACT FROM AUTHOR]

By 2020 Europe has to increase its energy efficiency and share of renewables in 20%. However, even accomplishing these challenging objectives Europe will be effectively wasting energy as we demonstrate in this paper. In our way towards a fully renewable scenario, we need at least to stop wasting energy in order to guarantee the energy supply needed for growth and comfort. We waste energy when we employ more primary energy than the final energy we ultimately use and this excess cannot be reutilized. In this paper we propose the WE (wasted energy) as a novel metric to measure the performance of energy systems and set up appropriate targets. The WE incorporates information about energy efficiency and renewable sources. Unlike European legislation, the WE considers them in an integrated way. This approach will help Member States to exploit their intrinsic capabilities and design their optimum strategy to reach their objectives. Using the information in Eurostat, we calculate the WE of Member States in EU-28 and their evolution. We also analyze illustrative examples to highlight strategies to reduce the WE, study the connection between economic development and WE, and provide a tool to diagnose the potential of improvement of an energy system. [ABSTRACT FROM AUTHOR]

Current oceanic hydrate research mainly focuses on its exploitation, but the subsequent storage and transportation of recovered gas is also necessary. To accelerate its commercial application and clarify the potential of liquefaction after hydrate exploitation, a rigorous simulation modelling was firstly conducted on the depressurization exploitation of hydrate coupled with recovered gas liquefaction in this paper. The energy performance was evaluated by energy consumption and efficiency analysis. The energy efficiency of the gas and liquid production process, liquefaction process, and the key influence factors of the whole process were studied separately. Results show that the energy efficiency ratio for depressurization exploitation reaches between 4.9 and 19.4, while that for the whole system of hydrate exploitation and liquefaction is only between 1.3 and 2.7 considering recovered gas combustion for power generation. The energy efficiency ratio of the whole system increases to between 2.6 and 4.3 powered by offshore wind farm. The largest energy efficiency reduction is up to 77.8% after recovered gas liquefaction compared with exploitation process. Therefore the storage process with lower energy consumption should be prioritized or the energy consumption should be optimized for the storage and transportation process after hydrate exploitation. [Display omitted] • A coupled system of natural gas hydrate exploitation and recovered gas liquefaction is proposed. • Rigorous process modelling is established and key influence factors are investigated. • Energy supply for the coupled system driven by ocean wind power is analyzed. • Exergy analysis results show energy efficiency ratio is 2.6–4.3. [ABSTRACT FROM AUTHOR]

This paper conducts a systematic study to address the problems of high flow loss and low energy efficiency of centrifugal pumps caused by the development of secondary flow within the impeller. Based on the forces balance in the direction perpendicular to the streamline, theoretical calculations are drawn to redesign blade thickness for a 5-blade centrifugal impeller to suppress the secondary flow. The correlations between the development of internal secondary flow within the impeller and energy efficiency of centrifugal pump under full flow rate conditions are illustrated by numerical simulations validated by experimental tests. Secondary flow coefficient and entropy production rate (EPR) are introduced and extracted to quantitative analysis the secondary flow level and energy loss inside the impeller. Results indicate that the blade redesign methods proposed here can efficiently inhibit the development of secondary flow and improve the energy efficiency. Moreover, the secondary flow coefficient introduced in this paper can quantitatively reflect the intensity of secondary flow under various flow rates of different impellers. Combining with the entropy production analysis of impeller, the consistent change trend of total secondary flow coefficient and entropy production reveals that the improvement of pump energy efficiency benefits from the reduction of turbulence EPR which results from the suppression of internal secondary flow. • Theoretical calculations of blade thickness for low specific speed centrifugal pump. • Blade redesign based on secondary flow suppression to improve energy efficiency. • Quantitative analysis of secondary flow and energy losses in the impeller. • Improvement of energy efficiency attributes to the reduction of turbulence EPR. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we expand the work of Brandt and Dale (2011) on ERRs (energy return ratios) such as EROI (energy return on investment). This paper describes a “bottom-up” mathematical formulation which uses matrix-based computations adapted from the LCA (life cycle assessment) literature. The framework allows multiple energy pathways and flexible inclusion of non-energy sectors. This framework is then used to define a variety of ERRs that measure the amount of energy supplied by an energy extraction and processing pathway compared to the amount of energy consumed in producing the energy. ERRs that were previously defined in the literature are cast in our framework for calculation and comparison. For illustration, our framework is applied to include oil production and processing and generation of electricity from PV (photovoltaic) systems. Results show that ERR values will decline as system boundaries expand to include more processes. NERs (net energy return ratios) tend to be lower than GERs (gross energy return ratios). External energy return ratios (such as net external energy return, or NEER (net external energy ratio)) tend to be higher than their equivalent total energy return ratios. [Copyright &y& Elsevier]

Abstract: Heat transfer intensification for shell and tube heat exchangers is an efficient technique to increase energy saving when retrofitting heat exchanger networks (HENs). Such intensification has been widely studied in the process industry in recent years from the point of view of individual heat exchangers. By implementing intensified techniques in existing exchangers, higher heat transfer coefficients can be achieved, leading to higher heat exchange duties in the existing matches, which can improve the overall energy recovery without the necessity to change the HEN configurations [1–3]. The conventional intensification techniques include tube-side enhancements (internal tube fins, twisted-tape inserts, and coiled-wire inserts), and shell-side enhancements (external tube fins, and helical baffles). Combining several enhancement techniques can achieve higher energy saving compared with single technique implementing. However, existing papers rarely considered different intensification techniques in the same case to compare their performances and examine combinations. It is difficult to identify which intensification technique is more suitable in a certain exchanger, or which combinations of intensification techniques are expected to contribute the most positively to the compound augmentation. Thus, this paper focuses on the recent advances on tube-side and shell-side enhancement techniques, and investigates their performances to obtain substantial economic benefits in intensified heat exchangers. [Copyright &y& Elsevier]

Abstract: Turkey is one of a number of countries who still lack a national management standard for energy. Industrial energy consumption accounts for 42% of Turkey''s total energy consumption. With the help of a questionnaire and analytical framework, this paper investigates Industrial Energy Management Practice in Turkey and highlights significant bottlenecks and shortcomings of energy intensive industries in terms of energy management application. The survey was carried out as a multiple case study of the Turkish iron, steel, cement, paper, ceramics and textile industries. Outcomes of the questionnaire are evaluated according to the analytical framework which covers company characteristics, regulations, external relations of the companies and internal organizational conditions. After analyzing these elements on the basis of a minimum requirement list, it was found that only 22% of the surveyed companies actually practice corporate energy management in Turkey. The main barriers to proper energy management implementation were identified as lack of synergy between the stakeholders, the extent and scope of energy manager courses, and inadequate awareness of and lack of financial support for energy management activities. As a guideline to overcome present obstacles, a set of policy options are offered: strengthening and restructuring of legal and institutional frameworks, promotion of energy efficiency, education, training and capacity building and facilitating implementation of the international energy management standard ISO 50001. [Copyright &y& Elsevier]

Abstract: To face global competition, and also reduce environmental and climate impact, industry-wide changes are needed, especially regarding energy use, which is closely related to global warming. Energy efficiency is therefore an essential task for the future as it has a significant impact on both business profits and the environment. For the analysis of possible changes in industrial production processes, and to choose what changes should be made, various modelling tools can be used as a decision support. This paper uses two types of energy analysis tool: Discrete Event Simulation (DES) and Energy Systems Optimisation (ESO). The aim of this study is to describe how a DES and an ESO tool can be combined. A comprehensive five-step approach is proposed for reducing system costs and making a more robust production system. A case study representing a new investment in part of a Swedish iron foundry is also included to illustrate the method''s use. The method described in this paper is based on the use of the DES program QUEST and the ESO tool reMIND. The method combination itself is generic, i.e. other similar programs can be used as well with some adjustments and adaptations. The results from the case study show that when different boundary conditions are used the result obtained from the simulation tools is not optimum, in other words, the result shows only a feasible solution and not the best way to run the factory. It is therefore important to use the optimisation tool in such cases in order to obtain the optimum operating strategy. By using the optimisation tool a substantial amount of resources can be saved. The results also show that the combination of optimisation and simulation tools is useful to provide very detailed information about how the system works and to predict system behaviour as well as to minimise the system cost. [Copyright &y& Elsevier]

Abstract: Improvement of energy efficiency has been accepted as one of the most cost-effective approaches towards sustainable economic development and reduction of the continuously increasing energy consumption internationally. South Africa, being among the developing countries, is not an exception even though historically low energy prices and the lack of appropriate policies have created an energy intensive economy. This paper examines the factors affecting the trends in energy efficiency in South Africa from 1993 to 2006 and particularly the impact of structural changes and utilisation efficiency of the country''s energy intensity. Identifying and understanding the driving forces are necessary ingredients in the development of appropriate policy-making. This paper also provides disaggregation of the energy efficiency trends in the main sectors of the economy. We determine that structural changes of the economy have played an important and negative role in the increasing economy-wide energy efficiency. On the other hand, the energy usage''s intensity was a contributing factor to the decreasing trend of energy efficiency. We suggest that differentiated price policies may be required if South Africa is to create an effective energy efficiency policy. [Copyright &y& Elsevier]

Abstract: This paper will summarise the European Strategy for Energy and Climate Change. In current international negotiations Europe has proposed a 20% reduction in GHG (greenhouse gases) in the developed countries by 2020 or 30% should there be an international agreement in the domain. However it is important to define measures to achieve the targets. One of the principal tools is to improve energy efficiency under the energy efficiency action plan, which will help to achieve a 20% energy saving by 2020. On the other hand, the amount of energy from renewable sources consumed in Europe will have to rise from its current level of 8.5%–20% by 2020. These are ambitious but achievable targets. Nonetheless, these can only be achieved through strong investment in areas of the knowledge triangle which strengthens research and innovation in the energy sector in Europe. The paper covers European Energy and Climate Change Policy, the European Strategic Energy Technology plan, the consequences of the Lisbon Treaty, European and national Road maps to a low carbon economy, the Energy Efficiency Plan for 2011 and finishes with a brief consideration of the EU’s energy infrastructure priorities. [Copyright &y& Elsevier]

Abstract: This paper aims at providing an identification and an analysis of the most relevant barriers to energy efficiency that limit a widespread implementation of the Best Available Technologies and Practices (BAT/Ps) through the investigation of 128 non-energy intensive manufacturing Small and Medium-sized Enterprises (SMEs) in Northern Italy. The study, starting from the existing literature, performs an investigation of the operational difficulties occurring when it has been decided to undertake the process of investing resources in energy efficiency interventions. The most perceived barriers have been analyzed with respect to several important characteristics (among others, sector and firm’s size). This examination shows also that very much attention should be paid to avoid bundling together SMEs of different sizes and sectors, since different behaviors with respect to the perception of the barriers can be observed. The analysis of the sample presents some interesting trends considering the perception of the barriers with respect to previous experience of the enterprises on energy efficiency. The paper also explores, through a preliminary analysis, the correlations among questions in order to understand the dynamics and the possible effects of a given barrier with respect to others. Several suggestions for future research in this important area have been provided. [Copyright &y& Elsevier]

Hydrogen is a key raw material for many chemical processes and a clean fuel for various power generation strategies. Coal-to-hydrogen (CTH) conversion is an alternative way to produce hydrogen that is applicable to the abundant coal reserves in China. The use of fossil energy has contributed to severe environmental problems, which drives the development of potential hydrogen production processes. Biomass is a promising renewable energy as well as an attractive resource for producing hydrogen, and it may address some of these environmental problems. In this paper, the simulation results of the biomass-to-hydrogen (BTH) and CTH processes were validated using available experimental data from the literature. Based on the simulation results, a techno-economic analysis was conducted from the viewpoints of the first and second laws of thermodynamics. The techno-economic analysis included determination of the energy efficiency, material consumption, total capital investment, production cost and carbon tax. The energy efficiencies of BTH and CTH were 37.88% and 37.82%, respectively. The BTH process had a larger raw material consumption and total capital investment (TCI) than the CTH process. However, the BTH process had a lower production cost and GHG emissions than the CTH process. The results of energy analyses of the BTH and CTH processes showed that the energy efficiency can be improved from a thermodynamic perspective. The combination of thermodynamic analysis and techno-economic performance evaluation provides insights into the improvement and operation of clean hydrogen production. • Biomass-to-hydrogen (BTH) shows better performances on production cost. • Coal-to-hydrogen (CTH) shows better performances on raw material consumption and TCI. • Techno-economic performance of CTH and BTH is conducted and compared. • BTH has a superior performance in terms of its resistance to price risk than CTH process. [ABSTRACT FROM AUTHOR]

Oil and gas offshore platforms present similar structural designs and include operations such as separation, compression and pumping. However, they handle large variations in the production of hydrocarbons and water over time. They may also follow different modes of operation depending on the field characteristics and fluid properties. It is therefore not possible to suggest a standard layout of an offshore platform that can be widely implemented in distinct petroleum regions. The oil and gas processing plant should be designed adequately to maximise the hydrocarbon production and minimise the power, heating and cooling demands. The utility plant should be designed appropriately to minimise the fuel consumption and cover the energy needs in all production phases. The present paper presents a generic methodology that addresses these challenges and builds on a combination of process simulation, energy analysis and optimisation routines. Possible platform layouts are sized, evaluated and ranked, based on preliminary estimates of the production profiles and petroleum properties. This methodology is applied to three case studies, derived from actual field data from Norway and Brazil, with different field conditions, fluid compositions (e.g. negligible, medium and high CO 2 contents of the well-fluids) and operational requirements (e.g. gas export, injection and lift). The results illustrate the benefits of the proposed methodology, as a comparison with the 'business-as-usual' case shows up to 25–30% energy savings and CO 2 -emissions along the field lifespan. • A novel methodology for designing and optimising energy-efficient platforms is presented. • Different petroleum compositions and production profiles are considered. • Various concepts for local power and heat generation and process design are assessed. • Energy savings and CO2-reductions can reach up to 25–30% compared to business as usual scenarios. [ABSTRACT FROM AUTHOR]

The energy retrofitting of residential stock is not always straightforward where heritage protected housing is concerned. In southern Europe, many examples built under the Modern Movement codes are now obsolete in terms of energy efficiency. The aim of this paper is to assess the potential for improvement of comfort conditions and energy efficiency in Mediterranean heritage residential buildings, through the incorporation of passive strategies in keeping with preserving heritage values. Long-term monitoring and field tests in representative flats of the case-study building were carried out and, focusing on a single example, adaptive comfort equations were used to assess results. The passive strategies considered are the thermal isolation of the air cavities of walls, changing window frames, optimizing window glazing, and setting up regular mechanical ventilation rates for indoor air changes. Although simulation results generally predict a better energy performance after testing retrofit strategies, the potential decrease in energy demand is more noticeable than the potential improvement in comfort conditions. • The improvement of comfort and energy efficiency in a heritage building is assessed. • Long-term monitoring and field tests were carried out in representative flats. • Passive strategies in keeping with preserving heritage values were examined. • Adaptive comfort equations were used to assess results focusing on one flat. • Energy efficiency improvements are more noticeable than those of comfort conditions. [ABSTRACT FROM AUTHOR]

The energy conversion efficiency of coal utilization is a focal point in modern energy management practices and in academic literature. This paper explores life cycle energy efficiency of coal (LEEC), which encompasses six distinct stages from the design of coal mines to the comprehensive reuse of resources. First, the study analyzes improvements to the evaluation of efficiencies in energy systems. Secondly, it proposes a multi-stage energy efficiency analysis and constructs an innovative LEEC model for coal exploitation and utilization. Thirdly, the energy efficiency of coal exploitation and utilization was evaluated, and found that total efficiency in China increased from 33.11% in 2010 to 37.69% in 2014, saving 126 Mtce of energy. Finally, this study found that mine design is the most important stage in improving energy efficiency, followed by the coal processing stage. Moreover, we found that coal processing has an indirect contribution to other stages in the life cycle utilization of coal, such as reducing transportation capacity. The primary research contribution is the development of a comprehensive LEEC model for the entire life cycle of coal, rather than just single-stage evaluation. This lays the foundation for further studies on energy efficiency of industrial chains and across entire systems. • Exploration of energy efficiency across the entire coal life cycle. • The energy efficiency of coal exploitation and utilization increased annually. • Analysis shows the implicit contribution of coal processing to life cycle. • Mine design is a crucial stage for overall life cycle energy efficiency. [ABSTRACT FROM AUTHOR]

High-powered, medium-speed diesel engines are widely used in merchant ships. Improving energy efficiency by using energy rationally is critical to reducing both environmental pollution and transport charges. In this paper, the energy efficiency of marine high-powered, medium-speed diesel engine is investigated. A new thermal cycle model of the marine engine is developed using AVL-Boost software. The thermodynamic data of the engine thermal cycle are obtained from the AVL-Boost software. The energy efficiency of the marine diesel engine is evaluated using both energy balance and exergy analysis. From the energy balance analysis, about 25% of the total energy is lost through exhaust heat. This forms the largest energy loss. However, using exergy analysis the largest energy loss originates from the irreversible exergy loss produced during the combustion process. This represents about 36% of the total energy loss. To explore ways to reduce energy loss and improve the energy efficiency, the effects of critical combustion parameters in the thermal cycle (combustion quality index, combustion starting angle and combustion duration angle) on energy distributions are discussed. The decrease in the combustion quality index, combustion starting angle and combustion duration angle (within a reasonable range) all contribute to reduce the total energy loss, increasing the indicated work and improving energy efficiency. • Evaluation of energy efficiency of high-powered medium-speed marine diesel engine by both energy balance and exergy analysis. • Model of diesel engine thermodynamic cycle is developed. • Effects of combustion parameters on energy loss are investigated to improve the energy efficiency. [ABSTRACT FROM AUTHOR]

Abstract This paper addresses the techno-economic, energetic and environmental assessment of the indirect and direct production of bioenergy using Pinus patula (PP) as raw material. Ethanol and synthesis gas are evaluated as main products through biochemical (fermentation) and thermochemical (gasification) routes, respectively. The complete characterization of the raw material was performed aiming to determine the chemical, proximate and elemental composition of the PP that is used as starting point for the simulation procedure. Mass and energy balances were obtained from the simulation of both processes using the software Aspen Plus v9.0. Different economic criteria such as Net Present Value (NPV) and Payback Period (PBP) were used to determine the profitability of both processes. The overall energy efficiency was calculated considering the relation between the energy content of the products and the energy content of the inputs (raw materials and utilities). The environmental assessment involves an attributional life-cycle assessment (LCA) of different systems such as seedlings production, PP cultivation, harvesting and collection, and the evaluated processes using a cradle-to-gate approach. As a result, the production of ethanol evidenced a low production cost (0.549 USD/L), higher energy efficiency (45.1%) and higher CO 2 emissions (0.17 kg per MJ EtOH) in comparison to the biomass gasification. Highlights • Pinus Patula as a potential raw material for direct and indirect bioenergy production. • Steam explosion linked to SSF make the ethanol production a profitable process. • Clear energy policies are required to improve the feasibility of biomass gasification. • The conversion of syngas in electricity has a negative effect on the energy efficiency. • High energy needs in the biochemical route contribute to the high environmental impact. [ABSTRACT FROM AUTHOR]

Abstract To address the global challenge of the climate change, more strict legislations worldwide on carbon emission reductions have put energy intensive industries under immense pressure to improve the energy efficiency. Due to the lack of technical support and financial incentives, a range of technical and economic barriers still exist for small-medium enterprises (SMEs). This paper first introduces a point energy technology, which is developed for SMEs to improve the insight of the energy usage in the manufacturing processes and installed in a local bakery. Statistical analysis of electricity consumption data over a seven-day period is conducted, including the identification of operational modes for individual processing units using an enhanced clustering method and the voltage unbalance conditions associated with these identified modes. Two technical strategies, namely electrical load allotment and voltage unbalance minimisation, are then proposed, which could attain more than 800 k w h energy saving during this period and the current unbalance could be reduced to less than 10%. In addition, the genetic algorithm is deployed to solve the job shop scheduling problem based upon the commercial electrical tariffs, and this reduces the electricity bill by £80 per day in the case study. Implementation of the recommendations based on the above analysis therefore may potentially yield significant financial and environmental benefits. Highlights • A monitoring system is developed to collect energy data at different granularity. • Identification of machine operational modes and voltage unbalance are analysed. • The working modes could be improved by two technical strategies. • The job shop scheduling problem is investigated with regard to tariffs. [ABSTRACT FROM AUTHOR]

Abstract The overall energy efficiency level of ethylene production process not only is influenced by the input energy mediums and output products, but also closely dependent on the operation status of the internal phases in the process. Traditionally, the energy efficiency diagnosis strategies mostly regard the ethylene production process as a black box, and only care about the influence caused by input and output factors, regardless of the interactions effect resulted from the internal subprocess and equipment. Therefore, to improve the traditional energy efficiency diagnosis schemes and extract the potential energy-saving factors, the deep analysis of the internal operation phases is necessary. Considering the large-scale and multi-dimensional characters of ethylene production process, a multi-level and multi-granularity energy efficiency diagnosis scheme is proposed in this paper. First, based on the analysis of energy flow, the layer classification for diagnosis boundary is implemented and the key energy-consuming facilities are determined in ethylene production process. Then, the corresponding three-level energy efficiency indicator system is established for benchmarking the energy efficiency level. Finally, the hierarchical energy efficiency diagnosis models are constructed based on two-stage and network data envelopment analysis to study the internal operation phases and find out the energy-saving factors. A practical Chinese ethylene plant is used to demonstrate the effectiveness of the proposed scheme. Not only is the energy efficiency level evaluated, but also the specific reasons resulting in the low energy efficiency level are found out, which provides the suggestions for saving energy and improving energy efficiency to the decision makers. Highlights • A hierarchical energy efficiency diagnosis scheme is proposed. • A hierarchical energy efficiency indicators system is established. • The energy efficiency diagnosis is carried out in multiple granularities. • The advice of energy saving obtained by the proposed scheme is more targeted. [ABSTRACT FROM AUTHOR]

Abstract The European Union has set specific targets for reducing energy consumption, shifting the main focus of European energy policy towards a firm commitment to enhancing energy efficiency. In light of the limited progress reported in Greece's energy efficiency action plan, the objective of this paper is to help redesign the near-term national policy framework. In this respect, a risk-oriented optimisation model is developed to support the optimal budget allocation to energy efficiency measures, with a view to achieving the 2020 national targets. The transdisciplinary methodological framework initially builds on the Energy Efficiency Action Plans for Greece and involves stakeholder engagement, multiple-criteria decision making and portfolio analysis. The evaluation of the policy instruments is based on two criteria, namely energy savings and implementation risk, under a set of technical and financial constraints. Finally, the robustness of both the optimal policy portfolios and the individual policies composing these portfolios is assessed. The results indicate that, given the financial and technical constraints, the 2020 target cannot be achieved. By stochastically analysing the impact of external uncertainty, three policies emerge as the most robust, while portfolios achieving savings of more than 1000 kTOE until 2020 are found highly vulnerable to underlying uncertainties. Highlights • Greece strives to achieve its national energy efficiency targets in the near-term. • We propose a risk-oriented framework to support the redesign of the national policy. • Given the financial and technical constraints, the 2020 target cannot be achieved. • Three policies appear to be robust and contribute the most in the optimal portfolios. • Policy portfolios achieving more than 1000 kTOE are highly vulnerable to uncertainty. [ABSTRACT FROM AUTHOR]

Abstract While the empirical literature on energy intensity is focused mainly on reduced energy intensity, this study examines a case where energy intensity is increasing. The paper aims at identifying price and non-price determinants of Iran's energy intensity and analyzing their importance in dynamics of it. In order to answer the research question, LMDI decomposition technique as well as time series econometrics have been used to data analysis. Based on the results, both structural changes in economic activities and inefficiency of energy consumption have led to the increase in Iran's energy intensity, although the latter dominated the former. The elasticity of energy intensity with respect to total factor productivity, real energy prices, and industrial development is negative in the short-run and long-run. Additionally, per capita income has a positive linear relationship with energy intensity that implies a high income elasticity of energy demand. Furthermore, changes in TFP and energy prices contribute more than two-thirds of forecast error variance decomposition of energy intensity, which shows the importance of these factors in energy intensity dynamics. Hence, in order to change the increasing trend of energy intensity, it is important to consider the necessities of improving technology and productivity while realizing energy prices. Highlights • Iran's economy faced an average annual growth of 3.3% in energy intensity between 1974 and 2014. • Both inefficiency and structural effects led to the increase in energy intensity of Iran. • Relative energy price and total factor productivity have key roles in energy intensity dynamics. • Economic growth based on TFP improvement will lead to declining energy intensity. • Industrial development strategy can has a significant role in energy productivity in Iran. [ABSTRACT FROM AUTHOR]