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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]

Within many industries there is a constant drive to reduce environmental impact and energy costs thereby ensuring maximum energy re-use. Within the iron and steel industry the ironmaking processes are acknowledged to be the focus area when the topic of energy saving arises. A lot of attention has been applied to the ironmaking processes with regards to environment and energy saving, with established technologies being in place to reach these goals such that the process per se, is now at or very close to theoretical limits. The following areas of the blast furnace process are currently the focus of Primetals activity with regards the target to further improve energy saving with incremental improvements: • Flue gas recycling within blast furnace stoves • MERIM dry gas cleaning process • Dry slag granulation including heat recovery This paper will present the concepts and latest status of the above technologies. The paper will review the progress to date of these development activities and thus present ideas on options for energy saving and re-use within the ironmaking system. [ABSTRACT FROM AUTHOR]

Reusable launchers have been studied under CNES contracts for more than 30 years, with early concepts such as STS-2000 or Oriflamme, more recently with very significant efforts devoted to Liquid Fly Back Boosters as with the Bargouzin project led with Tsniimash, TSTO with the Everest concept studied by Airbus-DS as prime contractor or the RFS Reusable First Stage concept of a large first stage associated to a cryotechnic second stage. These investigations, summarized in the first part of the paper, enabled CNES to identify clearly the technology requirements associated to reusability, as well as cost efficiency through detailed non-recurring costs and mission costs analysis. In parallel, CNES set in place development logic for sub-systems and equipment based on demonstrators, hardware test benches enabling maturation of technologies up to a TRL such that an actual development can be decided with limited risk. This philosophy has been applied so far to a large number of cases, such as TPTech and TPX for Hydrogen turbo pump, GGPX as demonstrator of innovative gas generator, HX demonstrator of modern cryotechnic upper stage with a dozen of different objectives (Thermal Protection, 20K Helium storage, measurements …). This virtuous approach, “learn as you test”, is currently applied in the phased approach towards scaled down reusable booster stage, whose possibility to be used as first stage of a microlaunch vehicle is under investigation. The selected technologies allow paving the way towards reusable booster stages for Ariane 6 evolutions or main reusable stage for a further generation of heavy launchers. The paper describes the logic behind this project, together with the demonstration objectives set for the various sub-systems as well as operations. [ABSTRACT FROM AUTHOR]

Abstract: In March 2011, China’s central government set a new challenging target of reducing its energy intensity by 16% during 2011–2015, after it had achieved a reduction of 19.1% during 2006–2010. And this new target was assigned to provincial authorities in August 2011. However, China’s provincial energy-economic developments are unbalanced and different provinces have different key sectors for energy conservation. Most previous studies focused on provincial energy efficiency at the aggregate level, or the three-industry level (or one-digit level). However, whether for policy decision or academic research, it is necessary to further subdivide the sectors. In this paper, we use three indicators (Gini Coefficient, energy consumption share and energy intensity) to compare provincial energy conservation potentials at the two-digit sector level. To our knowledge, this paper is the first one to identify the keys for energy conversation across the 31 provinces×65 sectors. And the results are shown in visualized maps and matrix tables to help identify the key province×sectors for energy conservation easier. This also helps the central and provincial governments to distinguish key sectors when they monitor the energy conservation progress. [Copyright &y& Elsevier]

Abstract: The closed greenhouse concept has been studied in this paper. The closed greenhouse can be considered as the largest commercial solar building. In principle, it is designed to maximize the utilization of solar energy by use of seasonal storage. In an ideal fully closed greenhouse, there is no ventilation window. Therefore, the excess heat must be removed by other means. In order to utilize the excess heat at a later time, long- and/or short-term thermal storage technology (TES) should be integrated. A theoretical model has been derived to evaluate the performance of various design scenarios. The closed greenhouse is compared with a conventional greenhouse using a case study to guide the energy analysis and verify the model. A new parameter has been defined in this paper in order to compare the performance of the closed greenhouse concept in different configurations – the Surplus Energy Ratio showing the available excess thermal energy that can be stored in the TES system and the annual heating demand of the greenhouse. From the energy analysis it can be concluded that SER is about three in the ideal fully closed greenhouse. Also, there is a large difference in heating demand between the ideal closed and conventional greenhouse configurations Finally, a preliminary thermo-economic study has been assessed in order to investigate the cost feasibility of various closed greenhouse configurations, like ideal closed; semi closed and partly closed conditions. Here, it was found that the design load has the main impact on the payback period. In the case of the base load being chosen as the design load, the payback period for the ideal closed greenhouse might be reduced by 50%. On the other hand, glazing type, ventilation ratio, and the closed area portion have a minor impact on the payback period. [Copyright &y& Elsevier]

Highlights • An integral methodology for the energy planning and grid assessment is proposed. • Four different battery technologies in the optimization response are analyzed. • The grid assessment includes the grid response and its reinforcements until 2050. • The techno-economic results for a 50% and 100% renewable energy targets are obtained. • The methodology used in this work can be applied by small islands or by the SIDS. Abstract This paper presents an energy planning, a grid assessment, and an economic analysis, considering three growing scenarios (Low, Base and High) in the electricity consumption, to supply the energy demand for a hybrid power system (Photovoltaics/Wind/Diesel/Battery) on a small island by 2050. The main aim of this study is to present a methodology to optimize and reduce the backup time of the battery bank, included from the hybrid power generation system selected. Also, it will compare four different battery technologies, simultaneously, without changes in the renewable energy targets settled in 50% until 2050 and without changes in the safe continuous operation of the grid. The methodology includes a grid assessment analysis to obtain a reliable, strong and safe operation response based on the grid code parameters, even in case of disturbance. In the proposed methodology the analysis is developed on the basis of the use of two simulation model tools. The First simulation model tool determines the optimal values of variables that the system designer controls, such as the mix of components (Photovoltaics/Wind/Diesel/Battery) that make up the system and the size or quantity of each variable. This model uses the multiyear analysis based on a time-domain simulation run at the energy-flow level with discrete time-steps of 1 h. The Second simulation model tool assumes all the variables and parameters on the grid as constants during the period of the time analyzed. The power flow is analyzed through a programming language command script function and reflects the system response at a specific time with given specific variables and parameters. The final technical proposal and its financial analysis are obtained applying and validating this methodology on a small island, as well as, the selection of the system to be installed for the renewable electricity generation. The electric grid modifications and reinforcements through the years until 2050, according to the grid code and the renewable energy targets settled for the island's electric power system are included. [ABSTRACT FROM AUTHOR]

Abstract: The present paper deals with the energy performance, energy classification and rating and the global environmental quality of school buildings. A new energy classification technique based on intelligent clustering methodologies is proposed. Energy rating of school buildings provides specific information on their energy consumption and efficiency relative to the other buildings of similar nature and permits a better planning of interventions to improve its energy performance. The overall work reported in the present paper, is carried out in three phases. During the first phase energy consumption data have been collected through energy surveys performed in 320 schools in Greece. In the second phase an innovative energy rating scheme based on fuzzy clustering techniques has been developed, while in the third phase, 10 schools have been selected and detailed measurements of their energy efficiency and performance as well as of the global environmental quality have been performed using a specific experimental protocol. The proposed energy rating method has been applied while the main environmental and energy problems have been identified. The potential for energy and environmental improvements has been assessed. [Copyright &y& Elsevier]

This paper attempts to explore carbon tax pilot in Yangtze River Delta (YRD) urban agglomerations based on a novel energy-saving and emission-reduction (ESER) system with carbon tax constraints, which has not yet been discussed in present literature. A novel carbon tax attractor is achieved through the discussion of the dynamic behavior of the new system. Based on the genetic algorithm-back propagation neural network, the quantitative coefficients of the actual system are identified. The scenario analysis results show that, under the same tax rate and constraint conditions, the ESER system in YRD urban agglomerations is superior to the average case in China, in which the impacts on economic growth are almost the same. The former’s energy intensity is lower and the shock resistance is stronger. It is found that economic property of YRD urban agglomerations is the main cause for the ESER system of YRD urban agglomerations being superior. In the current YRD urban agglomerations’ ESER system, energy intensity cannot be adjusted to an ideal level by commercialization management and government control; however, it is under effective control of carbon tax incentives. Therefore, strengthening the economic property of YRD urban agglomerations and effective utilization of carbon tax incentives could perfectly control energy intensity, without obvious potential negative impact on economic growth. [ABSTRACT FROM AUTHOR]

Eco-driving is one of the many options to reduce fuel consumption and emissions from transit operations. However, it is not yet clear how effective eco-driving is for different transit service and fuel types. As policymakers consider implementing eco-driving, they also need comparisons of eco-driving against other fuel-conserving strategies, such as purchasing alternative fuel vehicles. Using a case study of transit operations in Atlanta, Georgia, United States, this paper evaluated eco-driving for two very different service types – local urban service and express service. The authors simulated the implementation of transit eco-driving strategies using an innovative, streamlined algorithm designed to minimize fuel consumption by limiting instantaneous vehicle specific power while maintaining average speed and conserving total distance. Fuel consumption and fuel-cycle emissions were compared across the monitored driving cycles and their modified eco-driving cycles. The savings from eco-driving were also compared to fuel and emissions reductions expected via the conversion of the transit fleets to compressed natural gas (CNG), another popular fuel conservation strategy. The results showed that eco-driving would be a potentially very cost-effective strategy for local and express bus transit operations. [ABSTRACT FROM AUTHOR]

Waste energy recovery and utilization presents a crucial opportunity in primary energy reduction and energy efficiency improvement for the global iron and steel industry. However, lack of comprehensive and practical methodology, the exact quantity of waste energy is often poorly quantified. This paper develops an innovative techno-economic model to quantify this opportunity that links theoretical, technical, and economic potential with the characteristics of waste energy resources and waste recycling technologies. Various forms of waste energy, such as sensible heat, pressure energy, and chemical energy, were examined. In addition, four scenarios were established to evaluate future energy saving potential and energy consumption reduction under the synergistic effect of technology promotion and structure adjustment. Findings show that the proportion of practical potential is less than 20% when considering the technical implementation rate for the average industry value. The selected 35 energy-saving technologies contribute to 3.08 GJ/t crude steel of cumulative energy savings, and technology implementation plays a significant role in energy consumption reduction. A sensitivity analysis indicates that energy price and discount rate are the most sensitive factors. [ABSTRACT FROM AUTHOR]

In this paper a simple and fast re-configuration algorithm which is suitable for a PV array with Series–Parallel architecture is presented and discussed. The main advantage of such an algorithm is represented by its capability to find a nearly optimal configuration by testing only a very small subset of all the possible configurations. In particular it is shown that, in an actual PV array composed by 24 PV modules which operate under mismatching conditions (which are quite common in urban environments due to chimneys, streets lighting poles, antennas, neighboring buildings, etc.), the proposed algorithm is able to lead to energetic performances which are more or less comparable with those ones which can be obtained by adopting a Monte Carlo based algorithm employing a much higher number of trials. Moreover, by means of a specific example, it is shown that maximization of extracted energy and absence of dangerous operating conditions, possibly leading to the premature aging of the PV field and/or to hot spot phenomena, are contrasting requirements. It is nonetheless possible to find proper configurations able to lead to a suitable compromise between such two contrasting requirements. Further work is needed and is in progress in order to design suitable re-configuration algorithms able to identify such compromise configurations. [ABSTRACT FROM AUTHOR]

More than one-third of energy expenditure is attributable to buildings. Urbanization is leading to tighter spatial interrelationships among buildings, which is escalating building energy consumption due to the impact of buildings on one another. This, in turn, is exacerbating Urban Heat Island (UHI) effects. We sought a bio-inspired solution to this significant engineering issue and discovered a similar heat island effect in flowers, namely the “micro-greenhouse effect.” However, a special cooling effect has been observed in a temperate flower— Galanthus nivalis —which generates cooler intrafloral temperatures. In this paper, we studied the special retro-reflecting property of the flower petals, which has been suggested as a possible contributor to this cooling effect, and modeled a bio-inspired retro-reflective building envelope. We conducted cross-regional energy simulation of building networks in order to examine its thermal-energy impact. We found that building surface temperatures dropped considerably when neighboring buildings were retrofitted with a bio-inspired retro-reflective façade. We concluded that a bio-inspired retro-reflective building envelope can; (1) lessen the reflected heat of solar radiation in spatially proximal buildings leading to reduced UHI, and (2) reduce the energy required for cooling. These findings have broad implications for building design, urban planning, development of retro-reflective technology, and environmental conservation. [ABSTRACT FROM AUTHOR]

Policymakers are increasingly concerned about rebound effects, which lead to lower savings than expected when energy-efficiency increases. There are difficulties in making coherent comparisons between magnitudes of rebound effects in different sectors, such as home heating, industry and transport. A barrier to this in domestic heating is the conceptual difficulty of estimating rebound effects as energy-efficiency elasticities, since the large, stepwise increases in energy-efficiency through thermal retrofits fit uneasily with differential calculus. This paper offers a solution. Firstly, it develops a ‘cross-sectional’ method in which elasticity-based rebound formulae are used to estimate implied average rebound effects in large datasets of energy consumption and energy efficiency. It then shows how a simple power curve can model these datasets, simplifying the mathematics, giving ‘constant’ rebound effect results that are immediately meaningful, and extending compatibility to rebound effect modelling in other sectors. The method is then extended to case studies of thermal retrofits of individual dwellings. Here the inherent inaccuracy of using linear approximations in rebound effect formulas is also illustrated. The cross-sectional, ‘constant’ rebound effect methodology is offered for wider use in estimating rebound effects in case studies and in domestic heating as more datasets of energy consumption and efficiency become available. [ABSTRACT FROM AUTHOR]

The rebound effect, or the increased use of energy services following an increase in the efficiency of that service, is widely studied in the literature, but it is usually only considered in a single-service environment. Such a framework ignores the potentially significant indirect rebound effects that occur through increased purchasing power for other services and does not allow for joint efficiency improvements across many services, what we call "efficiency correlation." We develop a household production model with two energy services and distinct but simultaneous efficiency changes to test the implications of efficiency correlation on net energy elasticities and the rebound effect. Positively correlated efficiency choices across end-uses not only increase technically feasible energy reductions but also drive additional rebound responses that erode these savings. Model simulations suggest that the rebound effects through the efficiency correlation channel are just as large as traditional direct and indirect rebound effects reported in the literature, though they are offset by added technical energy savings. Moreover, we find that negative correlation can significantly reverse any energy savings (e.g. a household installs energy-saving window panes but then trades in their sedan for a SUV), but current Federal efficiency standards make this scenario unlikely. This paper offers new insight into a host of additional behavioral responses to efficiency improvements, particularly the incidence of efficiency correlation across different energy services, and highlights its implication for realized energy savings. [ABSTRACT FROM AUTHOR]

Abstract: The first objective of this paper is to map the adoption of technologies for the reduction of energy and resource consumption in production and the second is to test the relationship between the implementation of those technologies and the performance of manufacturing firms. The aim is to contribute to the identification of the characteristics of the manufacturing firms that use this kind of innovative technology in order to help policy makers promote energy and resource efficiency in a suitable manner. Our research is based on the Spanish and Slovenian subsamples of a wider European Manufacturing Survey. Our suggested models explain how significant energy efficiency is, and how much of the variability in economic performance and environmental performance it can explain. The results show that the use of energy and material saving technologies does not have a clear and significant relationship with economic performance. On the other hand a significant positive relationship is found between energy and material saving technologies and environmental performance. [Copyright &y& Elsevier]

Abstract: Low-income housing constitutes an important but often overlooked area for energy use reductions within the US residential sector. Given the scarcity of existing information on this subject, this study uses a semi-structured interview format to explore the key behavioral tendencies, energy knowledge gaps, and attitudes among low-income public housing residents, with the goal of demonstrating a process for developing, scoring, and analyzing the interviews that will be useful to other researchers when first engaging complex subjects like behavior in contexts that are not well covered by existing literature. Methods for sampling subjects and iteratively developing an interview guide and response-scoring framework are described, and the usefulness of this approach in allowing both quantitative and qualitative analysis of behavior response data is demonstrated. The paper concludes by illustrating how themes that emerge from the response analysis can be used to inform future surveying and intervention efforts. Key themes include the varying definitions for “comfort” amongst residents; the lack of resident control over the household environment; the tendency for residents to evaluate energy conservation measures (ECMs) in terms of costs, savings, and comfort; the muted differences in behavior between those who do and do not pay energy bills; and the importance of building maintenance and resident energy education to ongoing efficiency efforts. [Copyright &y& Elsevier]

Abstract: Recently, the concept of net zero energy buildings has become a major topic in the R&D work on future buildings. In order to achieve a zero energy balance on annual level energy saving and energy efficiency measures have to be fully exploited. However, a demand for active heating and/or cooling will remain in most buildings and under most climatic conditions. Solar energy is the main on-site renewable energy source which can be used to achieve a high fraction of renewable energies to cover the remaining energy demand in buildings. Main energy needs in buildings are due to heating and/or cooling, depending on local climatic conditions and type of building. In this paper principle ways of covering part of the demand for heating, cooling and domestic hot water by using solar technologies are discussed and a design study of a solar thermally driven heating and cooling system for a virtual hotel is presented. A model of the same hotel has been investigated under various climatic conditions in order to study the impact of sizing of key components on the overall performance. In addition an analysis of economic performance is presented for the example of the location Malta in Mediterranean Sea. [Copyright &y& Elsevier]

Abstract: In the last years, the growing demand for air conditioning has caused a significant increase in demand for primary energy resources. Solar-powered cooling is one of the technologies which allows to obtain, by using the renewable solar source, an important energy saving compared to traditional air conditioning plants. The paper describes different technical installations for solar cooling, their way of operation, advantages and limits. The objective of the present study has been to analyze the technical and economic feasibility of solar absorption cooling systems, designed for two different application fields: industrial refrigeration and air conditioning. The possibility to replace or integrate the existing plants is studied, by considering the refrigeration requirements of a company, which works in meat manufacturing, and the heating and cooling demands of a hotel located in a tourist town in Italy. In the first case, the system comprises an absorption chiller coupled to solar flat plate collectors, whereas the second application is about a hybrid trigeneration plant, known as thermo-solar trigeneration; this option allows having greater operational flexibility at sites with demand for energy in the form of heating as well as cooling, for example in a hotel. In this way the authors could compare different results obtained by a technical and economic experimental analysis based on existing users and evaluate the advantages and disadvantages in order to suggest the best solution for the two studied cases. [Copyright &y& Elsevier]

Abstract: Estimation of energy performance indexes, like the heating curve or the energy signature, requires robust regression of the heating losses on the outdoor temperature. The solution proposed in this paper is to use the range between the 1st and the 3rd quartile of the quantile–quantile (q–q) plot to check if the heating losses and the outdoor temperature have the same distribution and, if yes, to perform the regression in this range of the q–q plot. The result is a model that conserves its prediction performance for data sets of the outdoor temperature different of those used for parameter identification. The robust model gives the overall heat transfer coefficient and the base temperature, and it may be used to estimate the energy consumption for data sets of the outdoor temperature coming from different time—space locations. [Copyright &y& Elsevier]

This paper focuses on the critical role of power sources in the future energy economy. It highlights the disruptive nature of the new energy technologies that will come into play, addressing the problems of greenhouse emissions and reduced availability of fossil fuel reserves. The importance of power sources such as fuel cells and batteries is discussed and their inter-relationship with the hydrogen economy explored. Overall it is clear that improved methods of energy storage are of critical importance and these must be optimised both in terms of cost and energy density. There are important challenges to be addressed; however, very positive outcomes can be anticipated. [Copyright &y& Elsevier]