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Energy is one of the essential components for the social and economic growth of urban and rural communities worldwide. However, the lack of energy supply is one of the most significant challenges facing remote or local communities in Nigeria. Distributed generation systems based on renewable energy, conventional sources, or hybrid resources are possible energy production solutions for these communities. This paper, therefore, focused on providing an energy generation system based on photovoltaics (PV) and diesel generators (DG) for stand-alone applications. A comparative analysis was carried out to assess the impact of control strategies, namely load following (LF), cycle charging (CC), and combined dispatch (CD). The designed energy systems: 60 kW PV, 78.69 kW PV, PV-DG-LF, PV-DG-CC, and PV-DG-CD were simulated using HOMER Pro while technical, economic, and environmental indices were used as performance metrics. Simulation results showed that 60 kW PV generated 84,927 and 75,859 kWh, without and with temperature effect, respectively, with the corresponding unmet electric load (UEL) of 13.8 and 14.2%. The result further demonstrated that PV-DG-LF is the optimal design with the highest renewable penetration of 80.7% and the least annual total fuel consumption (TFC) of 6,594 l. The economic results further confirm the suitability of PV-DG-LF with the lowest fuel cost (FC) and moderate cost of energy (COE) of $219,934 and 0.302 $/kWh, respectively. The PV-DG-LF is found to be more environmentally friendly, with the least annual CO 2 emission of 16,629.652 kg. The study considers veritable strategies to achieve affordable, clean, and reliable energy in line with research efforts on realizing the sustainable development goal (SDG) 7. [ABSTRACT FROM AUTHOR]

To reduce the dependence on fossil fuel, Process Integration and energy efficiency are crucial in chemical process industry to minimise the consumption of fossil fuels and electricity demand through Heat Exchanger Network (HEN). Pinch Analysis is well established to optimal HEN design to maximize the energy recovery in a process. The stream matches for energy recovery in HEN is important to ensure the temperature potential is not wasted, which the temperature potential could be converted into mechanical work. Therefore, Exergy Analysis has been introduced to work with Pinch Analysis, which ensure the heat recovery stream matches with appropriate temperature differences to minimise the work potential (exergy) loss. This paper demonstrates how Pinch Analysis and Exergy Analysis is simultaneously applied to determine exergy targets (rejection, requirement and avoidable losses) in low temperature HEN. A novel numerical tool known as Exergy Problem Table Algorithm (Ex-PTA), is proposed in this paper as a numerical method to the conventional graphical representation in Extended Pinch Analysis and Design (ExPAnD) method. The proposed tool produces more realistic and achievable results. The net shaft work requirement of the refrigeration system is also determined together with the system COP. This paper explored the effect of setting heat exchangers' minimum approach temperature (ΔT min ) on the exergy targets for low temperature HEN design. The external utility requirement and unavoidable exergy losses increased with ΔT min , while avoidable exergy losses and energy recovery reduced with respect to ΔT min . The net power requirement of the system increased with the ΔT min increment, however, the system COP reduced due to higher increment rate of compression compared to expansion work generation. The optimal ΔT min was determined at 2 °C for heat recovery system in the case study based on super-targeting approach, which considers the total annualized cost, operating cost and capital cost. [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]

Over-capacity problem in refining sector and energy security for oil supply are critical issues for China’s oil industry. As governmental intervention plays a significant part in current and future development of oil industry, over-capacity problem would not be solved without macro-regulatory. Though China is promoting large-scale strategic reserve of crude oil, there is rare quantitative evaluation on the capability of the oil industry in dealing with import disruption. In this paper, a system dynamic model is established for oil supply chain analysis. Based on the model, a quantitative measurement is proposed to evaluate the over-capacity extent of refining industry. The over-capacity extent is classified into three levels, according to varied demand fluctuation the supply chain is expected to deal with. By comparing the modeling results and historical data of 2012 and 2013, we conclude that over-capacity in China’s refining industry is in the severest level. The measurement reveals the driven-force of over-capacity from supply chain perspective, and demonstrates a quantitative method to figure out the proper capacity of energy supply industry. Second, the model simulates how oil supply chain responds to crude oil import disruption and the subsequent impacts. The modeling results indicate that the current configuration of China’s oil supply system is able to maintain sustainable supply under a less-than-180-day crude oil import disruption. The model provides a supply chain perspective in looking into energy security issues, and reveals the relationship between strategic petroleum reserve and the capability to cope with supply risks. In summary, the system dynamic model proposed in this paper is applicable for analysis on capacity planning and reserve strategy design of oil supply chain, providing valuable suggestion for the future development of China’s oil industry. The design concept and method of the model can be used for analysis of other energy industry. [ABSTRACT FROM AUTHOR]

Recognizing the industrial sector's high energy use and vast potential for energy saving, many national governments have established voluntary or negotiated agreements that set quantitative energy-saving targets for individual industrial enterprises. The most commonly used energy-saving targets worldwide are volume and energy intensity targets. Since 2006, the Chinese government has set mandatory, enterprise-level energy-saving targets in terms of the “amount of energy saved”; this represents a unique category that differs from both volume and energy intensity targets. Based on first-hand data collected at ten case enterprises, this paper represents one of the first attempts to verify the reliability of the amount of energy saved data reported by the Chinese government and to rigorously and systematically investigate the inherent weaknesses of the amount of energy saved targets through a comparison with the mainstream categories of energy-saving targets. The ten case enterprises reported four different types of amount of energy saved. While all of the case enterprises claimed full achievement of their amount of energy saved targets, four enterprises exaggerated their performance by violating the National Standard for Calculating the Amount of Energy Saved of Enterprises. The paper thus hypothesizes that the National Top-1000 Enterprise Program's alleged achievement of performance 65% higher relative to its amount of energy saved target is likely an overestimation. Although amount of energy saved targets constitute an innovative energy-saving indicator, they do not represent a step forward from conventional volume and intensity targets because of the following four weaknesses: 1) amount of energy saved targets provide limited potential for comparison given the different types of amount of energy saved and the different calculation methods, 2) they generate uncertain environmental outcomes as it is possible to meet a portion of an amount of energy saved target through production volume expansion, 3) they are difficult to enforce due to the complexity of data verification on the part of local government agencies, and 4) they are poorly correlated with the national target for reducing energy intensity. Amount of energy saved targets should therefore be replaced with “double-control” targets that impose both volume and intensity targets on industrial enterprises. [ABSTRACT FROM AUTHOR]

Given that the first industrial revolution was based on Steam Engine (coal as energy source), and the second on oil and electricity, where both these revolutions are actually "high carbon" revolutions, it is logical to expect that the third industrial revolution should be based on systems of renewable energy sources (RES), in order to minimize the problems arising from climate changes and to achieve sustainable development. However, the usage of the RES technologies and daily/weekly storage of energy and their connection to smart grids is not enough for the expected third industrial revolution. The start of this revolution would require technologies that have a great potential for further development and ability to supply, at any time, the necessary energy and power to a settlement/city, as well as drinking water, meeting the peak load requirements, continuously throughout the year, and independently of external sources of energy and drinking water. This would be provided from intermittent RES energy (solar, wind, etc.) and sea or other unclean source of water as natural resources. In that context, this paper presents a radically new technological solution: Key Engine which uses only natural resources: the sun, sea and gravity, in order to continuously and simultaneously supply a consumer with energy, power and drinking water. This solution has all the essential features required to start a third industrial revolution. The basic unit of Key Engine consists of the solar thermal (ST) generator with parabolic trough collectors through which sea water flows directly, absorbing thermal energy of solar radiation. After the separation of steam from seawater, the steam drives turbines and generators and produces electricity that is delivered to Pump Storage Hydroelectric (PSH) facility with seawater, which balances the daily and seasonal surpluses and shortages of energy, thus ensuring a continuous supply of electric power and energy to a consumer. At the same time, the water that comes out of the turbine, passes through the water treatment unit and is stored in drinking water reservoir, enabling continuous supply of the same consumer with drinking water. The paper presents theoretical aspects of Key Engine, model for optimal sizing and practical formulas for the calculation of characteristic values of the system, which could be the basis for further scientific research, development and innovative solutions that would help engineers in practice for numerous and diverse applications of Key Engine. In order to verify the derived mathematical relationships and models for optimizing the Key Engine in real conditions, the case study of the island of Vis in the Adriatic Sea, Croatia, has been considered, along with total annual irradiance of 1575 kW h/m 2 a, total annual electric energy consumption of 20 GW h and drinking water consumption of 453,382 m 3 . The obtained results: power of ST generator of 52 MW, working volume of the upper reservoir of 7 hm 3 , total annual electric energy production of 62 GW h/a, and drinking water production of 480,754 m 3 /a, clearly show that the new technology can fully meet the needs of the considered consumer for energy and drinking water. As the basic idea of Key Engine relies on the use of natural resources, i.e. RES energy and sea, the paper presents only the starting solution, whereby, apart from the sun, RES can be wind, or other renewable sources, that can perform separation of vapor from seawater and thus produce drinking water, as well as energy simultanously. Also, energy storage may not be performed solely by the PSH technology, but also by any other technology that can provide seasonal balancing of energy. All this suggests that the Key Engine can be understood as an open-source for RES technology development and thus bring changes in all three aspects of sustainable development: economy, society and environment. [ABSTRACT FROM AUTHOR]

The latest report from the Intergovernmental Panel on Climate Change urges that global CO 2 emissions from the power sector should be reduced by 90 percent or more below 2010 levels between 2040 and 2070. Such a reduction will most likely require greatly increasing the share of wind, solar, energy storage and nuclear energy in the energy mix in the next 40–50 years. This paper emphasizes the importance of developing large energy storage systems without which, wind and solar can only have a limited impact on CO 2 emissions as it will depend mainly on the energy mix used during wind and solar down time. The large areas that are required would be challenging, but not unrealistic, as long as a solution for energy storage exists. Carbon capture and storage has considerable potential to reduce CO 2 emissions from coal and gas power plants, but also from heavy industries such as cement and steel manufacturing. To give an idea of the scale of the required infrastructure, in the United States, coal and gas power plants emit approximately 2.4 billion tonnes of CO 2 per year; whereas the US annual petroleum consumption is about 0.9 billion tonnes (6.9 billion barrels). This paper also emphasizes that uranium and thorium used in breeder reactors represent an almost infinite source of low-carbon energy. The issues associated with the management of nuclear wastes are real, but they are not the uniquely difficult issues perceived by the media, much of the public and by many politicians. Finally, the investment necessary to implement a wind and solar powered economy would very likely be higher than that necessary to implement a nuclear powered economy because of the much larger number of GWe required. [ABSTRACT FROM AUTHOR]

In this paper, an IAM (integrated assessment model) uses a newly-developed Monte Carlo analysis capability to analyze the impacts of more aggressive U.S. residential and commercial building-energy codes and equipment standards on energy consumption and energy service costs at the state level, explicitly recognizing uncertainty in technology effectiveness and cost, socioeconomics, presence or absence of carbon prices, and climate impacts on energy demand. The paper finds that aggressive building-energy codes and equipment standards are an effective, cost-saving way to reduce energy consumption in buildings and greenhouse gas emissions in U.S. states. This conclusion is robust to significant uncertainties in population, economic activity, climate, carbon prices, and technology performance and costs. [ABSTRACT FROM AUTHOR]

This paper presents the energy performance evaluation of a marketable net-zero-energy house (NZEH): Solark I at Solar Decathlon China 2013. The assessment methodologies are based on EnergyPlus simulations and measured data. The paper also discusses the reasons for the differences between the results of the simulations and the measurements, analyzes the investment cost, summarizes the lessons learned from the competition, and presents the potential for replicability and transposition from Solark I to implementation in a practical NZEH. The conclusions are that Solark I's investment cost is reasonable, its systems for building-integrated photovoltaics, hot water and heating, and ventilation and air conditioning demonstrated excellent performance based on the results of the energy performance evaluations using EnergyPlus simulations and measured data. Thus, Solark I is a marketable NZEH. [ABSTRACT FROM AUTHOR]

China has surpassed the United States to be the world's largest energy consumer, but a lot of energy was used to produce products for exporting to other countries. Presently, China faces a great challenge in energy security and environmental protection. This paper focuses on the energy embodied in China's foreign trade with a multi-regional input–output approach. Three versions of the GTAP (Global Trade Analysis Project) database were used to capture the trend and distribution of the embodied energy flows for China during 2001–2007. The results indicate that the energy embodied in the global trade is increasing rapidly, growing faster than the total direct energy exported in the same period. China is shown as an energy exporter in terms of embodied energy, and the embodied energy trade surplus increased from 156 million tons of oil equivalents (Mtoe) in 2001 to 514 Mtoe in 2007, with a proportion of domestic energy consumption increased from 14% to 23%. This paper also studies the effects of the energy-intensive industry restrictive export policy of China, and we find that this policy could reduce the national energy consumption and promote industrial structure upgrades effectively. However, the expansion of energy-intensive industries in other countries may reduce China's efforts for global energy saving and global warming alleviation. Our simulation shows that carbon leakage is about 50%. [ABSTRACT FROM AUTHOR]

Evaluating the environmental sustainability performance of a nation is complex. This paper considers the merits of environmental indices, and how effective they are when assessing the environmental sustainability of any nation. The simplicity and generic qualities of environmental indices currently necessitates a much broader analysis in order to evaluate any nation׳s genuine environmental sustainability credentials – ultimately the development of a synthetic Environmental Sustainability Index is required to fulfil this task. Using Iceland as a case study, this paper reviews the usefulness of four selected environmental indices (Environmental Vulnerability Index, Environmental Performance Index, Ecological Footprint and Happy Planet Index) for governance institutions when formulating reasoned responses to challenges. By adopting a holistic methodology, Iceland׳s environmental sustainability credentials are critically examined in this paper, with particular focus given to the impacts deriving from expanded renewable energy utilisation in recent years. Abundant geothermal and hydropower energy resources have been increasingly used to power heavy industry, particularly aluminium production. The wider health implications and long-term environmental sustainability consequences of renewable energy utilisation have not been analysed in depth within any of the indices. Socio-economic progress in Iceland has also been attained alongside the imposition of the highest ecological footprint of any nation in the world. As such, economic activities in Iceland have not occurred in accordance with commonly accepted notions of sustainable development, which is focused upon the reconciliation of economic, environmental and social objectives, together with recognition of current and future need across these domains. [ABSTRACT FROM AUTHOR]

Abstract: Foreseeing a promising future of utilizing bio-energy, more and more small-scale biomass power plants are recently built. Biomasses with high moisture content such as sludge or Empty Fruit Bunch are often used as fuel in small-scale power plant without proper drying. These highly moist biomasses reduce the efficiency of the boiler but on the other hand drying the biofuel is also an energy intensive process. This paper aims to investigate how drying would affect the overall energy efficiency while proper heat integration in between the drying and power plant is under consideration. A 12.5 MW biomass power plant that burns EFB with 60 wt% moisture is used as a base case. Two types of dryer, Hot Air Dryer (HAD) and Superheated Steam Dryer (SSD), are proposed for the drying process. These two dryers require heat at different temperature levels to provide a better chance for heat integration. Material and energy balance models of the dryers and boilers are derived in this paper and the steam power plant model is constructed in Aspen Plus. The results of this study show that with proper drying and heat integration, the overall efficiency can be improved by more than 5%, when compared to process without drying. [Copyright &y& Elsevier]

Abstract: Industry uses around one third of the world’s energy, and accounts for about 40% of global carbon dioxide emissions. There is increasing economic and social pressure to improve efficiency and create closed-loop industrial systems, in which energy efficiency plays a key role. This paper describes some of the key concepts involved in modelling the energy flows in manufacturing, both for the building services and the industrial processes. Detailed dynamic energy simulation of buildings is well established and routinely used, working on a time series basis – but current tools are inadequate to model the energy flows of many industrial processes. There are also well-established models of manufacturing flows, used to optimise production efficiency, but typically not modelling energy, and usually representing production and material flows as event-driven processes. The THERM project has developed new software tools to model energy-related and other utility flows in manufacturing, incorporating these into existing thermal models of factory buildings. This makes it possible to map out the whole energy system, and hence to test efficiency measures, to understand the effect of processes on building energy use, to investigate recycling of heat or cooling into other processes or building conditioning, and so on. The paper describes some of the key concepts and modelling approaches involved in developing these models, and gives examples of some real processes modelled in factories. It concludes that such models are entirely feasible and potentially very useful, although to develop a tool which comprehensively models both energy and manufacturing flows would be a major undertaking. [Copyright &y& Elsevier]

Abstract: Well designed Renewable Energy (RE) policies and their effective regulation is the key to promote RE generation in the world. Renewable Energy Certificate (REC) mechanism is a market-based policy instrument which facilitates Renewable (Energy) Purchase Obligations (RPOs) in order to increase RE generation in a country. The recently conceived and implemented REC mechanism in India attempts to involve various stakeholders in an economically efficient manner and has been effective in its first year of operation. The paper commences with the background and the genesis of REC mechanism in India. It characterises the REC trading mechanism and analyses the performance of the REC market for the FY 2011–12. Comparing the financial viability for sale of RE by project developers in certain key states, the paper shows that REC mechanism is more profitable than entering into a Power Purchase Agreement (PPA) for sale of RE at Preferential Tariff (Feed-in-Tariffs). Thus, the REC market which has attained a size of 2.3 billion INR in its first year of existence is forecasted to grow manifold in the future and the paper attempts to forecast the market size in near term. Further analysis of the REC market reveals that although there are inherent advantages of the REC mechanism over other methods of promoting growth of RE, the market is currently subject to various distortions and the paper suggests few steps for correcting these distortions by appropriate market re-design. The paper concludes that the REC market mechanism has gained momentum and can effectively promote RE generation in an economically efficient manner, with benefits to all stakeholders, provided it is strictly implemented and continuous corrections are given in the right direction by the market regulator. [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: 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]

Abstract Theses on China's low-carbon economy focus on the driving forces of carbon emissions, energy–carbon efficiency, and the carbon–economy nexus. Meanwhile, comprehensive frameworks that assess China's green economy and also analyze its driving forces are lacking. This paper constructs a green productivity index based on the Global Malmquist–Luenberger productivity index to evaluate the development of the low-carbon economy in China. A panel vector auto-regression model is adopted to further analyze the endogenous interactions and dynamic relationships among aspects of the green economy and its influencing factors. Empirical results show that China has seen a balanced development of green economic growth in 2000–2016, achieved in a series of clear stages. To maintain the sustainable growth of the low-carbon economy in the future, China must rely more on technological progress. This research also makes some important discoveries that have not been found in previous studies: the impact of China's industrial structure and energy consumption structure on the green economy are short term, having a duration of impact of approximately four years. Finally, we provide an assessment of provincial green economy development and describe the corresponding policy implications. Graphical abstract Image Highlights • A comprehensive analysis of China's green economy. • A slack-based Global Malmquist–Luenberger index is adopted to calculate the Green Productivity Index in China. • The stage characteristics of green economic development are identified. • A panel vector autoregressive model is used to analyze the interactions among aspects of the environmental economic system. • The findings that the impact duration of energy structure, industry structure, and urbanization on the green economy is about four years. [ABSTRACT FROM AUTHOR]

The paper analyses the effect of renewable and non-renewable energy consumption as well as the regime type on economic growth in 30 Sub-Saharan African (SSA) countries over the period 1980–2012. Using heterogeneous panel cointegration and panel-based error correction tests, we find long-run relationship between the variables. However, short-run results are not robust, which suggest that energy sector investments are long-term in nature. Specifically, the results show that while both renewable and non-renewable energy have significant positive effect on economic growth, non-renewable energy has a greater growth enhancing effect than renewable energy. A 10% increase in renewable energy consumption is associated with an increase in economic growth by 0.27%, while a 10% increase in non-renewable energy consumption leads to an increase in growth by 2.11% ceteris paribus. Further, the findings of the study show that democratic states experience higher growth rates than autocratic states. [ABSTRACT FROM AUTHOR]

The objective of this study is to trace and quantify the sources of rebound effect for different energy sources in China. This paper decomposes the economy-wide rebound effect into 135 production sector-level rebound effects and five final demand components. The sector-level rebound is further decomposed into output effect and substitution effect. A two-stage decomposition method and a static computable general equilibrium model are developed to achieve this. Five types of energy-specific efficiency improvements are introduced, respectively, in all the production sectors. Results show that improving efficiency of using coal leads to the smallest macro-level rebound. For rebound decomposition, four findings are generalized. First, final consumption shows larger impact on the rebound of secondary energy sources than on primary energy sources. Second, production sectors that are big user of the efficiency-exposed energy source are expected to be key rebound contributor. Third, energy-producing sectors make negative rebound contribution. Results also show that, substitution effect is the predominant mechanism that triggers sector-level rebound. Policy implications are also discussed. [ABSTRACT FROM AUTHOR]

Energy has been the major input for the national economies. While fossil-based energy resources are diminishing, researchers are focusing on alternative fuels and various technology options for conversion, distribution, and end user's operating environment processes. As the search for the alternative pathways for the “sustainable economy” idea continues, management factor is getting considerably important within each phase of energy generation and consumption. In this paper, we employ a hybrid multi-criteria decision-making methodology to evaluate the energy management performance of selected nine countries with a focus on Turkey with respect to a number of criteria. The hybrid approach integrates three methods, viz. Analytical Hierarchy Process, Multi-Criteria Optimization and Compromise Solution, and Technique for Order Preference by Similarity to Ideal Solution. It enables decision-makers assess multiple alternatives within an analytic framework while considering multiple criteria simultaneously. We perform our analysis for each year between 2001 and 2016. The results show that, with its fast-growing population, dynamic economy, and huge energy saving potential, Turkey displays a low profile compared to the other countries in our scope. Our results can be encompassed by in-depth analyses and long-term plans to shift the country's energy technology selection strategies to more efficient, cost-effective and cleaner options. [ABSTRACT FROM AUTHOR]

Industrial systems management is nowadays increasingly devoted to improve the control of most critical production aspects. In this context, the performance of all the systems involved in production processes have to be measured and analysed in order to get better insights in terms of potential production and quality improvements as well as energy savings. In order to evaluate the performance of a certain system, a possible and effective way is to compare it with data from similar systems, thus to conduct a benchmark analysis. In the area of energy management, although the compressed air system (CAS) is one of the most important and energy consuming services within industrial plants, enterprises often have difficulties understanding and appreciating the entity of potential benefits coming from the improvement of its energy efficiency. The present paper aims at developing a new benchmark analysis for compressed air systems in industrial plants. The proposed methodology starts from the KPIs (Key Performance Indicators) already available in the scientific literature for CASs’ energy performance and is mainly based on the analysis of a huge real dataset collected from over 15,000 energy audits made on a wide range of different companies, all related to produced quantity of compressed air and energy consumed by CASs. Collected data present some limitations and related improvements and corrective actions have been undertaken and are presented in the followings. Data analyses have been followed by complementary surveys regarding compressed air systems’ use, maintenance and monitoring practices performed within several Italian enterprises and aimed at enhancing and creating a more reliable baseline for benchmarking. [ABSTRACT FROM AUTHOR]

There is a significant difference in the performance of waste cooking oil-to-energy companies in China. Most biofuel companies face a loss while a few others have high recovery rates and strong profitability. To shed light on this phenomenon and to aide in formulating policy, this paper constructs a framework from the two dimensions of X-Y and investigates the impact of government intervention on biofuel companies' performance by taking two companies located in the kitchen waste-to-resource pilot cities of Changzhou and Suzhou. Results indicate that: (1) the basic policy instruments of information disclosed and fee and penalty mechanisms in Changzhou are inferior to those of Suzhou. On the other hand, capital investment and cooperation between stakeholders are better in Changzhou. As for the value chain dimension, the policies are similar in both cities. This means that companies involved in the recycling of waste cooking oil and biofuel production equally neglect research and development, preferential loan and product sales by government. (2) In terms of effectiveness, recycling rates and company profits for Changzhou Yueda Kate New Energy Co. Ltd. are far below those of Suzhou Clean Environmental Technology Co. Ltd. Whether the biofuel companies are authorized by government or not, fee and penalty mechanisms and information disclosure are the key determinants affecting performance of biofuel companies. (3) There is still some room to improve the performance of Suzhou Clean Environmental Technology Co. Ltd. Policies can focus on the following: strengthening R & D, which improves the technological supply and diffusion capability of biofuel companies; building the demand-typed policy frame and adjusting policy structure; improving the market structure of biofuel companies. [ABSTRACT FROM AUTHOR]

The demand for the energy has increased drastically as a result of the rapid growth in industrialization, urbanisation and higher standard of living. One such potential substitute to fossil fuels is biodiesel that ensures sustainable energy source. The selection of appropriate source of biodiesel and proper blending of biodiesel plays a major role in alternate energy production. In the present work, a novel hybrid Multi Criteria Decision Making (MCDM) technique was proposed to evaluate and select the optimum fuel biodiesel blend for the IC engine with conflicting criteria to enhance the energy efficiency. Exploratory analysis were carried out on a single cylinder four stroke, air cooled, constant speed, direct injection diesel engine with a rated output of 4.4 kW at 1500 rpm at different loads. Two hybrid MCDM models, namely Fuzzy TOPSIS and Fuzzy VIKOR were proposed. Fuzzy was applied to determine the relative weights of the evaluation criteria whereas TOPSIS and VIKOR were applied to obtain the final ranking of alternatives. Diesel, B20, B40, B60, B80 and B100 fuel blend alternatives are prepared by varying the proportion of biodiesel for MCDM model. Similarly BTE, MRPR, NO x, CO 2 , CO, HC, SMOKE, ID, CD and Exhaust gas temperature were considered as the evaluation criteria. The ranking order by Fuzzy TOPSIS is based on closeness coefficient and Fuzzy VIKOR is based on VIKOR index. In Fuzzy TOPSIS, B40 stands first at 50% and 75% load conditions and second at 25% and full load conditions respectively. In Fuzzy VIKOR, B40 stands first at 25% and 50% conditions and second at no load, 75% and full load conditions respectively. The ranking of alternatives as obtained by both Fuzzy-TOPSIS and Fuzzy-VIKOR is B40 > B20 > Diesel > B80 > B60 > B100 and B40 > B20 > Diesel > B60 > B80 > B100. From the results, it was observed that both the methods indicated that B40 is the best blend to operate the engine. Hence, it is concluded that mixing 40% biodiesel with diesel is suggested as a good partial replacement for diesel. This paper highlights a new insight into MCDM techniques to evaluate the best fuel blend for the decision makers such as engine manufactures and R& D engineers to meet the fuel economy and emission norms to empower the green revolution and energy management. [ABSTRACT FROM AUTHOR]

This paper provides an overview of the power sector development in Iran for the period 1984–2014. A retrospective optimization approach is applied to assess economic and environmental benefits that would have been achieved through appropriate long-term planning. MESSAGE, a systems engineering optimization model, is used for this analysis. Two alternative scenarios are defined to explore the impact of supply- and demand-side strategies on the power generation mix, fuel consumption and CO 2 emissions. The focus on the past choice of energy scenarios provides some insights for future scenario design. The results of the cost-optimal scenarios with international fuel prices are compared with the actual historical development. The findings indicate that the demand-side strategies are key drivers in achieving a low-carbon generation mix. Least-cost scenarios would favor much more combined cycle, renewable technologies and distributed electricity generation units, and less gas turbine than the actual transition pathway. Long-term energy planning would have reduced the cumulative total power system costs by $21-$90 billion. [ABSTRACT FROM AUTHOR]

There is a large amount of water consumption embodied in energy production. Driven by a growing population and economy, the energy sector will continue to expand, increasing more pressure on the fresh water demand of countries. This paper analyzes the energy–water nexus embodied in international energy trade via a combination of input–output analysis (IOA) and ecological network analysis (ENA). The energy–water element nexus is depicted based on a mixed-unit IOA to investigate the parallel relationship between energy and water. ENA is used to uncover energy–water pathways intertwined in global energy trade and identify the pair-wise relationship between countries according to the energy–water pathway nexus. Then, a case study of the international energy–water nexus of China is conducted. The results of energy–water nexus element analysis show that water use per unit of energy products in the country is much greater than those of other countries. Moreover, indirect water use during energy production deserves more attention, which is often neglected in water resource management. The results of energy–water nexus pathway analysis demonstrate that international energy trade has a positive effect on China’s water condition, mitigating serious water shortage problems but increasing dependency on other countries and regions. Mutual relationships among trading countries are described using utility and control analyses. The results show that system integrality is arguably more critical in determining system behavior than direct effects alone. Europe changes from a beneficiary in direct mutual relationships to a contributor in integral utility mutual relationships, whereas Australia has an opposite change. Although China has a dominant position in direct relationships, it becomes an equal competitor with the USA in utility mutual relationships. China depends heavily on most countries, especially those in South and Central America, the Middle East, Africa, and Australia. The network mutualism index (=0.56) and synergism index (=9.187) indicate that the current global energy trade network has negative relationships within a competitive environment. Finally, policy and economic suggestions are put forward to alleviate the potential impacts of international energy trade on water scarcity in China. [ABSTRACT FROM AUTHOR]

Renewables are going to make our planet a better place to live. These clean resources of energy can bring a handful of advantages to the future electricity industries. Nevertheless, the large percentage of renewables integration can cause some operational issues, in power systems, which are needed to be identified and coped with. This paper defines, classifies and discusses the latest flexibility treatments in power system based on a comprehensive literature study. The current work specifically considers the abilities, barriers, and inherent attributes of power systems’ potential to deal with high integration of Variable Generations (VGs) in future flexible power systems. [ABSTRACT FROM AUTHOR]

Access to electricity is limited in rural areas of Myanmar, where the majority of the population live. Myanmar׳s rich solar resource and the recent price drop in solar PV modules indicate initial suitability for rural solar electrification systems to meet the electricity demand. In many parts of Myanmar, women are responsible for supporting the family financially. The ability of rural women in Myanmar to take advantage of solar PV powered services to improve their lives depends on concurrent progress towards addressing the many dimensions of gender equality – empowerment, health, education, opportunity, voice, representation, and livelihood-in rural locations. This paper examines the barriers of solar PV applications and the potential for women led solar PV enterprise development in rural Myanmar. Although the entrepreneurial process is the same for men and women in theory, in practice different factors e.g. social/cultural, religion, economic and educational ultimately result in the disadvantaged status of women-led enterprises. Therefore, widespread and long-term eventuation of this potential in Myanmar depends on a government committed to renewable energy resources for rural electrification and to diligently and holistically addressing geographical, political, educational, financial, ethnic and technical barriers to the empowerment of a rural, female population. [ABSTRACT FROM AUTHOR]

More than a decade ago, in China׳s electric power industry, the investment for generation side and power grids was inadequate and the gap between power supply and demand kept enlarging. In order to relief the problems above, power industry reform has been carried out in 2002 under the guidance of “No. 5 Document” by the Central Government. The reform in 2002 has made a series of achievements, including the enhancement of operation efficiency of power industry and the fulfillment of power demand all over the country. During the past decade, as the rapid development of the society and economy, the external environment of China׳s power industry has changed greatly. However, the pricing and planning mechanism of China׳s power industry still operates following the requirements of “No. 5 Document”, this has led to a number of problems including twisted pricing mechanism, irrational power system planning, inefficient utilization of renewable energy and so on. These problems have not only hindered the development of power industry in China for quite a long time, but also brought negative influence on the business operation of upstream and downstream industries. Therefore, Chinese government has issued “No. 9 Document” in 2015 and launched a new round of power industry reform. Policies were carried out to form new pricing mechanism, new policies about renewable energy generation and power system planning process to solve the problems mentioned above. This paper has reviewed the history of reform in 2002 and summarized the existing problems of China׳s power industry. Besides, the main policies of “No. 9 Document” were deeply analyzed, and their significance as well as backwards were illustrated. At last, solutions were proposed accordingly and these solutions have considerable theoretical and practical significance to China׳s electric power industry reform in the future. [ABSTRACT FROM AUTHOR]

India has an active participation in global solar energy contribution through the Jawaharlal Nehru National Solar Mission (JNNSM) and its many states are also walking hand in hand with the national government through individual state solar policies. The state of Gujarat, through the ‘Gujarat Solar Power Policy 2009 (GSPP 2009)’, has been leading the country in solar power generation. The feed-in-tariff based GSPP 2009 is a unique experiment of the state to develop individual solar projects as well as public-private partnership based large-scale ‘solar parks’. Of the about 2700 MW (in September 2014) installed solar energy capacity in India, Gujarat occupies a share of more than 900 MW. This paper, through semi-structured in-depth interviews conducted with project developers involved in implementation of the Charanka solar park, Gujarat, investigates the industry perspectives on the GSPP 2009. With an installed capacity of 216 MW (in April 2012), the Charanka Solar Park is the Asia׳s largest solar park. Findings from this study indicate that the attractive fixed feed-in-tariff and strong implementation mechanisms are the key strengths of the policy. On the other hand, the key challenges are lack of trust of financial institutions on solar energy projects, and tradability and bankability of the solar power purchase agreements. [ABSTRACT FROM AUTHOR]

The smart metering and communication methods used in smart grid are being extensively studied owing to widespread applications of smart grid. Although the monitoring and control processes are widely used in industrial systems, the energy management requirements at both service supplier and consumer side for individuals promoted the evolution of smart grid. In this paper, it is aimed to disclose in a clear and clean way that what smart grid is and what kind of communication methods are used. All components of a smart grid are introduced in a logical way to facilitate the understanding, and communication methods are presented regarding to their improvements, advantages, and lacking feature. The developing generation, transmission, distribution and customer appliances are surveyed in terms of smart grid integration. The communication technologies are introduced as wireline and wireless classification where the key features are also tabulated. The security requirements of hardware and software in a smart grid are presented according to their cyber and physical structures. [ABSTRACT FROM AUTHOR]

Wind energy is becoming more important in recent years due to its contribution to the independence of power generation industry from traditional fossil energy resources and availability of continuous harvest-able potential on earth approximately around 10 6 MW . This paper presents a comprehensive overview of grid interfaced wind power generation systems. This is intended to provide a wide spectrum on the status of wind profile, wind potential estimation, configuration/design of wind energy conversion systems, wind generators, power converter topologies used for grid integration of wind power, energy storage systems for wind power applications, power smoothing methods, HVDC links used for wind integration, international grid codes and maximum power point tracking methods to the researchers, designers, manufacturers, and engineers working on the grid interfaced wind power generation. More than 200 research publications on the topic of grid interfaced wind power generation systems have been critically examined, classified and listed for quick reference. This review is ready-reckoner of essential topics for grid integration of wind energy and available technologies in this field. [ABSTRACT FROM AUTHOR]

As a direct consequence of power systems restructuring on one hand and unprecedented renewable energy utilization on the other, the uncertainties of power systems are getting more and more attention. This fact intensifies the difficulty of decision making in the power system context; therefore, the uncertainty analysis of the system performance seems necessary. Generally, uncertainties in any engineering system study can be represented probabilistically or possibilistically. When sufficient historical data of the system variables is not available, a probability density function (PDF) might not be defined, they must be represented in another manner i.e. using possibilistic theory. When some of the system uncertain variables are probabilistic and some are possibilistic, neither the conventional pure probabilistic nor pure possibilistic methods can be implemented. Hence, a combined solution is needed. This paper gives a complete review on uncertainty modeling approaches for power system studies making sense about the strengths and weakness of these methods. This work may be used in order to select the most appropriate method for each application. [ABSTRACT FROM AUTHOR]

Large wind farms are gaining prominence due to increasing dependence on renewable energy. In order to operate these wind farms reliably and efficiently, advanced maintenance strategies such as condition based maintenance are necessary. However, wind turbines pose unique challenges in terms of irregular load patterns, intermittent operation and harsh weather conditions, which have deterring effects on life of rotating machinery. This paper reviews the state-of-the-art in the area of diagnostics and prognostics pertaining to two critical failure prone components of wind turbines, namely, low-speed bearings and planetary gearboxes. The survey evaluates those methods that are applicable to wind turbine farm-level health management and compares these methods on criteria such as reliability, accuracy and implementation aspects. It concludes with a brief discussion of the challenges and future trends in health assessment for wind farms. [ABSTRACT FROM AUTHOR]

This paper introduces an improved total-factor ESTR (energy-saving target ratio) index, which combines the sequence technique and the “energy direction” to a DEA (data envelopment analysis) model, in order to measure the possible energy saving potential of a manufacturing sector. Afterward, the energy saving potentials of four different energy carriers, namely coal, gasoline, diesel oil and electricity, for 27 manufacturing sectors during the period of 1998–2011 in China are calculated. The results and its policy implications are as follows: (1) the average ESTRs of coal, gasoline, diesel oil and electricity are 1.714%, 49.939%, 24.465% and 3.487% respectively. Hence, energy saving of manufacturing sectors should put more emphasis on gasoline and diesel oil. (2) The key sectors for gasoline saving is the energy-intensive sectors, while the key sectors for diesel oil saving is the equipment manufacturing sectors. (3) The manufacture of raw chemical materials and chemical products sector not only consumes a large amount of oil, but also has a low efficiency of oil usage. Therefore, it is the key sector for oil saving. (4) Manufacture of tobacco and manufacture of communication equipment, computers and other electronic equipment are the benchmark for the four major energy carriers of energy-saving ratios. [ABSTRACT FROM AUTHOR]

The energy-water nexus of the water supply, wastewater treatment and power generation systems has been well discussed. It is very clear that one source cannot be produced or supplied without involving the other source. Since the two systems are intertwined with mutual needs, it is difficult to resolve the issues associated with them in isolation. However, combined solutions through integrated approaches may not be feasible in all situations. Therefore, it is important to consider the energy or water autarky (self-sufficiency) of these systems. If these systems can achieve autarky for the energy and water needs independently, such configurations can be considered sustainable. This review paper presents the energy and water needs for water supply, wastewater treatment, and power generation systems and critically examines the potential opportunities for achieving energy and water autarky in these systems. A detailed view of the water supply and wastewater treatment systems’ energy footprint was presented and similarly the water footprint of various power plants. Different approaches for achieving energy autarky in the wastewater treatment systems as well as approaches for water autarky in the power generation systems were discussed. It is imperative that future developments should consider an integrated design approach to improve the overall system autarky by communicating between the two individual systems, by considering synergistic energy-water production, by collaborating resources planning and energy-water infrastructure synergies supported by science and system-based natural resource policies and regulations. [ABSTRACT FROM AUTHOR]

The currently developing concept of a Net Zero Energy Building introduces new challenges and research problems. The calculation of a net zero energy balance is heavily influenced by the energy carrier weighting factors that are chosen, which can deeply influence the future energy market towards adopting specific energy technologies. The following paper proposes an analysis of different definitions and conventions for Net Zero Energy Buildings that employ different calculation methodologies and apply different weighting factors to an Italian case study. The case study, which is called “the Leaf House”, is one of the first examples of a nearly net zero energy building in Italy. A building simulation and model calibration were performed using monitored data. Energy balances were calculated for the case study. Scenarios for a building redesign were then proposed, with the aim of reaching an electricity target of net zero energy. Reaching a primary energy building balance of net zero is easier when using symmetric weighting because it allows renewable energy to account for avoided national mix energy generation. The results show that symmetrical balances are nearly fulfilled for the existing building and asymmetrical ones are below zero. In the redesign scenarios, the symmetrical weighting scenarios exceed the zero target by 34.10 and 20.83 MWh/year. The asymmetrically weighted balances show a variable trend in that auto-consumption and high load-matching are highly favourable because the theoretical ‘zero auto-consumption’ scenario would yield the worst result and would be the only one below the Net Zero threshold. Although symmetric weighting approaches could be viewed as robust physical approaches for renewables (e.g., the primary energy conversion factors for PV are usually close to 1), they can become a heavy burden during the market development of renewable energy technologies, highly favouring auto-consumption and energy storage to minimise energy import from the grid. [ABSTRACT FROM AUTHOR]

Energy piles have recently emerged as a viable alternative to borehole heat exchangers, but their energy efficiency has so far seen little research. In this work, a finite element numerical model is developed for the accurate 3D analysis of transient diffusive and convective heat exchange phenomena taking place in geothermal structures. The model is validated by reproducing both the outcome of a thermal response test carried out on a test pile, and the average response of the linear heat source analytical solution. Then, the model is employed to carry out a parametric analysis to identify the key factors in maximising the pile energy efficiency. It is shown that the most influential design parameter is the number of pipes, which can be more conveniently increased, within a reasonable range, compared to increasing the pile dimensions. The influence of changing pile length, concrete conductivity, pile diameter and concrete cover are also discussed in light of their energetic implications. Counter to engineering intuition, the fluid flowrate does not emerge as important in energy efficiency, provided it is sufficient to ensure turbulent flow. The model presented in this paper can be easily adapted to the detailed study of other types of geothermal structures. [ABSTRACT FROM AUTHOR]

The Swedish energy audit program is a publicly financed program, mainly targeting small and medium-sized firms to help them finance energy audits. By examining suggested and implemented energy efficiency measures from the energy audits conducted in 241 firms in the program, the aim of this paper is to examine the energy efficiency implementation gap and the cost efficiency of the program. The audits show that the firms' average annual energy efficiency improvement potential is between 860 and 1270 MWh/year which corresponds to a total energy efficiency improvement potential of between 6980 and 11,130 MWh/firm. The implementation rate of the suggested energy efficiency improvement measures in the SEAP is 53%. The program has resulted in investments in energy efficiency improvements between €74,100and €113,000/firm. [ABSTRACT FROM AUTHOR]

With low energy intensity and great potential for growth, the commercial sector has become one of the key sectors for energy conservation and emission reduction in the context of China's rapid urbanization process. Based on the EIA (Energy Information Administration) statistical methods, this paper calculates the energy consumption of China's commercial sector from 1981 to 2012, specifies the determinants of commercial energy demand, forecasts future energy consumption and estimates the energy conservation potentials using the Johansen co-integration methodology. The results indicate: (i) GDP (Gross Domestic Product) and urbanization have positive effects on the energy consumption of the commercial sector while labor productivity and energy price contribute to reduction in the sector's energy consumption. (ii) Under the basic scenario, energy consumption of the commercial sector will be 317.34 and 469.84 Mtce (million tons of coal equivalent) in 2015 and 2020 respectively. (iii) Under the moderate and advanced scenario, about 187.00 and 531.45 Mtce respectively of the energy consumption of the commercial sector can be conserved from 2013 to 2020. The findings have important implications for policy-makers to enact energy-saving policies. [ABSTRACT FROM AUTHOR]

Based on data of China׳s power industry from 2005 to 2010, this research applies the SBM approach of the dynamic DEA model (one of the efficiency measurement methods that corresponds with economy–energy–environment trinity) to analyze the Energy-Efficiency-Dynamic Total Factor Productivity (ECDTFP 1 1 Energy-Efficiency-Dynamic Total Factor Productivity (ECDTFP), a total factor productivity which considering the influence of environment efficiency, energy efficiency and economic efficiency. In our paper, this ECDTFP are drawn from the DSBM model. ) of the power industry and the efficiency effect of changing investment structure on the industry. The results indicate that the introduction of foreign capital and the reform to lower the share of state investment are conducive to raise the ECDTFP in the power sector. In addition, it is important to focus on vital factors such as the production structure, the industry concentration and the regional technology investment intensity, which significantly affect the productivity of the power sector in future policies and reforms. [ABSTRACT FROM AUTHOR]

The growing conflict between economic growth, energy and environment in China has restrained the country's economic development. In this work we investigated the interaction among the Chinese economy, energy production and consumption and the impacts of concomitant air emissions from 2000 to 2011, using an indicator system based on energy, emergy and money units. The results show that China's rapid economic growth has promoted tremendous expansion in energy production and consumption, which have led to increasing the impact of emissions in this study period. During the time examined, energy production and use efficiencies and the structure of the energy sector improved slightly; the self-sufficiency of energy use fluctuated, as petroleum took on an increasingly strong dependence on imports; fossil energy, mainly coming from coal, still has a majority share in energy production and consumption of the nation; the environmental loading intensity of energy consumption decreased slightly while that of energy production increased; most of the impacts of energy-related emissions are derived from their impact on human health; the impact of emissions from energy production made an increasing contribution to the total impact. Generally speaking, China's economic growth still heavily depends on energy-intensive industries that put great pressure on energy supply and pollution control. Although China has made obvious progress in energy mix optimization to save energy and reduce emissions, the pace of improvement still fell behind that of economic growth. Finally, this paper discussed some related issues and presented corresponding suggestions to further coordinate the relationship between the economy, energy production and consumption and the environment. [ABSTRACT FROM AUTHOR]

How to coordinate the relationships between economy, energy and environment is a complex issue for China. This paper presented an indicator system based on energy, emergy and monetary units to explore the interactions between China׳s economic growth, its energy production and consumption, and the related air emissions during 1995-2011. The results show that (1) China׳s energy utilization efficiency is continuously raised whilst the total production efficiency is just slightly improved; (2) petroleum import has surpassed international warning line (50%) since 2007, and it is further challenging China׳s energy security; (3) basic energy mix is still mainly composed of coal and petroleum; (4) air emissions׳ impact from energy production has climbed rapidly whilst that from energy consumption has declined slowly. Air emissions׳ impact from energy consumption still has main contribution to the total emissions׳ impact whilst that from energy production has an increasing share. Therein, air emissions׳ impact mainly comes from the impact on human health. While air emission intensity from energy consumption decreases obviously, that from energy production generally increases; (5) generally, the relationships between the structures of economy and energy and air emissions have become more coordinated. Compared with structure coordination degree, the improvement of scale harmony degree between the three aspects is much slower due to rebound effect, which will seriously challenge the presented targets in 12th Five-Year-Plan (FYP). Promoting the synergistic effect should become the underlying strategy for future economic sustainable development. [ABSTRACT FROM AUTHOR]

Subsidies to fossil-fuel consumption have made China's energy system fragile and unsustainable. It is necessary for China to reform fossil-fuel subsidies and reflect the resource cost and environmental cost in energy prices. Considering the life-cycle external costs, this paper estimates the scale of fossil-fuel subsidy and the true cost of renewable energy in 2010 and evaluates impacts of increasing renewable energy subsidies and phasing out fossil fuel subsidies on macro-economy and energy system in China based on scenario analysis. Simulation results show that the negative impacts on economic growth can be reduced from 4.460% to 0.432%, if only 10% of fossil fuel subsidies were removed. Increasing subsidies for renewable energy has positive impacts on macroeconomic variables. Although the economic benefits per unit of subsidies for renewable energy are lower than those for fossil fuels by 0.06-0.19 CNY, the revenue gap can be narrowed by shifting more subsidies from fossil fuels to renewables. Increasing subsidies for renewable energy helps optimize China's energy system in three ways: the first is making energy consumption structure cleaner; the second is improving energy efficiency; and the third is addressing the problem of imbalanced distribution and consumption of energy. [ABSTRACT FROM AUTHOR]

Exergy analysis and exergoeconomics are often used to evaluate industrial energy systems performance from the thermodynamic and economic points of view. While the classical exergy analysis can be used to recognize the sources of inefficiency and irreversibilities, so called advanced exergy analysis is convenient for identifying real potential for thermodynamic improvements of the system by splitting exergy destruction into avoidable and unavoidable parts. In this paper, the advanced exergy analysis is used to identify performance critical components and the potential for exergy efficiency improvement of a complex industrial energy supply plant. This plant is a part of a rubber factory and its role is to provide steam, compressed air and cooling water to the production facilities, as well as hot water for space heating and sanitary use. The plant is first analyzed as is and the avoidable (and the unavoidable) part of exergy destruction is identified for each observed component. Then, the measures for removing the avoidable destruction are defined. Finally, the plant is analyzed as if the measures were implemented and avoidable losses eliminated. Numerical analysis is based on real data, some of which are collected during on site measurements. Large system of nonlinear and linear equations is defined and solved numerically using the Engineering Equation Solver. Results of the presented analysis show the difference in thermodynamic and economic operational parameters of the plant for the cases without and with the efficiency measures implemented, i.e. the current state and the state with the avoidable irreversibilities eliminated. Beside obvious increase of exergy efficiency and enhancement of other thermodynamic parameters, certain improvement in the economy of the plant could be achieved. [ABSTRACT FROM AUTHOR]

Abstract: Energy saving is becoming increasingly important in batch processing facilities. Multipurpose batch plants have become more popular than ever in the processing environment due to their inherent flexibility and adaptability to market conditions, even though the same flexibility may lead to complexities such as the need to schedule process tasks. These are important features to producing high value added products such as agrochemicals, pharmaceuticals, polymers, food and specialty chemicals where the demand has grown in recent decades. Many current heat integration methods for multipurpose batch plants use a sequential methodology where the schedule is solved first followed by heat integration. This can lead to suboptimal results. In this paper, the heat integration model is built upon a robust scheduling framework. This scheduling formulation has proven to lead to better results in terms of better objective values, fewer required time points and reduced computational time. This is important as inclusion of heat integration into a scheduling model invariably complicates the solution process. The improved scheduling model allows the consideration of industrial sized problems to simultaneously optimize both the process schedule and energy usage. Both direct and indirect heat integration are considered as well as fixed and variable batch sizes. [Copyright &y& Elsevier]

Abstract: The growing concerns about climate change and security of supply opened way to a significant investment in the exploitation of RES (renewable energy sources) for electricity generation. The possibility of achieving 100% RES systems is being debated but concerns about costs, storage and backup capacity still prevail. This paper addresses the topic of renewable energy scenarios for the electricity sector, analyzing different possible future strategies for the Portuguese system. Each one of these strategies is characterized according to the expected electricity consumption and renewable share, with the final aim of analyzing a possible 100% RES scenario. The energy system analysis tool EnergyPLAN was used for simulating each scenario for a one year period. The 100% RES scenario is found to be theoretically possible but a significant increase on the total capacity of the system would be necessary to ensure no shortfall during the summer season. The outcome would be the existence of critical excess electricity production during the winter and also a significant increase of the total cost of the system. The importance of the interconnection as stabilization measure along with the inclusion of storage systems is discussed for a system highly dependent on renewable energy sources. [Copyright &y& Elsevier]

Abstract: In Hungary, there is a need for detailed alternatives to its fossil-based, highly import-dependent energy system. In this paper, an energy model of the Hungarian energy system of 2009 is worked out, as a reference model for a 100% renewable-based scenario. The model is created in the EnergyPLAN software and is able to simulate all sectors of the national energy system on an hourly basis. The EnergyPLAN software and the main issues of its first Hungarian application are presented. The model is validated by comparing its results to Hungarian and international statistics for 2009. Two alternative models – ‘Natural gas + biomass’ and ‘Biomass’ – were created in EnergyPLAN for an analysis to see how the energy system of 2009 could have been operated in an optimised way from environmental point of view, within the existing infrastructure. In ‘Biomass’ alternative model, the utilisation of primary renewable energy sources almost doubles, causing a decrease of 10% in carbon-dioxide emission. By changing the distribution of fuels by a different power plant utilisation, more favourable fuel consumption characteristics could have been achieved from the environmental point of view in 2009. [Copyright &y& Elsevier]

Abstract: Energy is a key input in investment decision making with a well-known effect on economic growth. Inelasticity of energy demand urges an understanding of its price dynamics. This paper makes a joint analysis of the price of oil, natural gas, and electricity in U.S. markets using a multi-regime specification that captures the stylized facts of energy prices. Oil and natural gas returns have similar regime dynamics and are well characterized by a high and low volatility regime. Electricity returns have to be parameterized with more regimes: a low volatility, a price spike, and a mean-reverting regime. The California crisis period stands out as a sole regime with extremely high volatility. Our methodology allows the synchronization among regimes to be studied and we find that electricity prices tend to be synchronized in U.S. wholesale markets, while natural gas returns show synchronization with electricity returns in the low volatility regime. [Copyright &y& Elsevier]

Abstract: Hydrogen, within the so called Hydrogen Economy, has the potential to become the energy carrier of the future which could change entirely the energy industry. It could help to change to a more reliable, efficient and environmentally friendly energy sector. Hydrogen Economy is based on different technologies which are related to the scientific and industrial sectors. Thus, all equipment included within hydrogen technologies are in an experimental stage or in a too early market, safety being one of the research lines followed in the design and use of these equipment and devices. This paper includes the design and implementation of different building works to have a place to operate in a safe way electrolyzers and fuel cell systems that belong to a research project in which Centro Nacional del Hidrógeno (CNH2) is taking part in its current facilities. Because of working with hydrogen, the whole design was considered from the point of view of the potential to generate explosive atmospheres. [Copyright &y& Elsevier]

Abstract: Energy and material saving considerations, as well as economic incentives, have led toward making effort for producing more efficient heat exchange equipment such as solar air heaters, heat exchangers. In order to enhance the heat transfer rate to flowing air in the duct of solar air heater and heat exchangers various turbulence generators viz. ribs, baffles and delta winglets are considered as an effective technique. Investigators reported on various turbulators in literature for studying heat transfer and friction characteristics in a duct of solar air heaters and heat exchangers. An attempt has been made in this paper to carry out an extensive literature review of various turbulators investigated for enhancing heat transfer and friction in solar air heaters and heat exchangers. The correlations developed for heat transfer and friction factor in solar air heaters and heat exchangers by various investigators have been presented and reviewed. [Copyright &y& Elsevier]